Article

Performance evaluation of a multi-image 3D reconstruction software on a low-feature artefact

Authors:
To read the full-text of this research, you can request a copy directly from the authors.

Abstract

Nowadays, multi-image 3D reconstruction is an active research field and a number of commercial and free software tools have been already made available to the public. These provide methods for the 3D reconstruction of real world objects by matching feature points and retrieving depth information from a set of unordered digital images. This is achieved by exploiting computer vision algorithms such as Structure-From-Motion (SFM) and Dense Multi-View 3D Reconstruction (DMVR). In this work, we evaluate the performance of a low-cost commercial SFM DMVR software by digitising a Cycladic woman figurine. Although the surface properties of the specific artefact are considered 3D laser scanner friendly, its almost featureless white-grey surface composes a challenging digitisation candidate for image based methodologies as no strong feature points are available. We quantify the quality of the 3D data produced by the SFM DMVR software in relation to the data produced by a high accuracy 3D laser scanner in terms of surface deviation and topological errors: We question the applicability and efficiency of two digitisation pipelines (SFM DMVR and laser scanner) in relation to hardware requirements, background knowledge and man-hours. This is achieved by producing a complete 3D digital replica of the Cycladic artefact by following both pipelines.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

... The field of application of photogrammetric methods based on SFM-MVS varies depending on the scale of investigation, from 3D reconstruction of artefacts in the cultural heritage sector to monuments of historical interest and archaeological excavations [5,6]. Recent scientific studies have attempted to evaluate the applicability of photogrammetric method in relation to the purpose of the study and the quality of the expected models [4]. For photogrammetric acquisition of the moulds, we We carried out a preliminary mineralogical (XRD) and petrographic analysis of these five moulds in order to verify their lithological nature. ...
... 3D digitalization is increasingly being adopted in archaeological studies, and research efforts in this field aim to identify workflows that guarantee the best performance in relation to processing time and costs for the production of 3D digital replicas. Each workflow involves the use of different hardware, software and digital sensor solutions [4]. In recent years, several software solutions have become available for the reconstruction of 3D objects from images using a combination of Structure-From-Motion (SFM) and dense Multi-View Stereo Reconstruction (MVS) algorithms. ...
... The richer the surface to be detected, the more effective the SFM algorithm will be. In order to obtain a point cloud or a dense polygonal mesh, SFM is coupled with MVS algorithms that calculate the correspondence of information for each pixel of the images and the corresponding depth maps [4]. The field of application of photogrammetric methods based on SFM-MVS varies depending on the scale of investigation, from 3D reconstruction of artefacts in the cultural heritage sector to monuments of historical interest and archaeological excavations [5,6]. ...
Article
Full-text available
Stone moulds were basic elements of metallurgy during the Bronze Age, and their analysis and characterization are very important to improve the knowledge on these artefacts useful for typological characterization. The stone moulds investigated in this study were found during an archaeological field survey in several Nuragic (Bronze Age) settlements in Central Sardinia. Recent studies have shown that photogrammetry can be effectively used for the 3D reconstruction of small and medium-sized archaeological finds, although there are still many challenges in producing high-quality digital replicas of ancient artefacts due to their surface complexity and consistency. In this paper, we propose a multidisciplinary approach using mineralogical (X-ray powder diffraction) and petrographic (thin section) analysis of stone materials, as well as an experimental photogrammetric method for 3D reconstruction from multi-view images performed with recent software based on the CMPMVS algorithm. The photogrammetric image dataset was carried out using an experimental rig equipped with a 26.2 Mpix full frame digital camera. We also assessed the accuracy of the reconstruction models in order to verify their precision and readability according to archaeological goals. This allowed us to provide an effective tool for more detailed study of the geometric-dimensional aspects of the moulds. Furthermore, this paper demonstrates the potentialities of an integrated minero-petrographic and photogrammetric approach for the characterization of small artefacts, providing an effective tool for more in-depth investigation of future typological comparisons and provenance studies.
... The latest generation of photogrammetry software is characterized by the replacement of earlier "close-range" methods-designed for individual point measurement and relying on coded survey targets to estimate relative locations of cameras within a scene (Luhmann 2010)-with highly automated alternatives. The latter, often labeled "imagebased modeling," first determines camera locations by methods known as Structure from Motion (SfM), and then computes dense 3D surface models of the scene with Multi-View Stereo (MVS or DMVR) (Koutsoudis et al. 2013). Here, we use "photogrammetry" to refer generally to the procedures of image-based modeling and distinguish the SfM and MVS stages when appropriate. ...
... Here, we argue that it is necessary to move beyond the initial phase of wonderment at our new capabilities to create life-like 3D imagery from a set of photographs to the matter of creating a consensus about what should constitute standard practice for archaeological photogrammetry. Our focus is on data collection during fieldwork, in particular the large-scale recording of trenches and architecture, rather than on small-object photography-a process deserving consideration on its own right (Koutsoudis et al. 2013;Porter et al. 2016). Steps for processing photogrammetric models are also too complex to address effectively here, and we instead refer the reader to previous discussions (Olson et al. 2013;Douglass et al. 2015). ...
... The requirements for capturing very small objects are different (c.f. Koutsoudis et al. 2013;Olson et al. 2013;Lerma and Muir 2014;Nicolae et al. 2014;Porter et al. 2016). Large sensors are advantageous, but they have a relatively narrow DOF in comparison to compact sensors (TABLE 2). ...
Article
Full-text available
Archaeologists have recently embraced photogrammetry as a low-cost, efficient tool for recording archaeological artifacts, active excavation contexts, and architectural remains. However, no consensus has yet been reached about standard procedures for reliable and metrically accurate photogrammetric recording. The archaeological literature describes diverse equipment and approaches to photogrammetry. The purpose of this article is to open a discussion about when and how photogrammetry should be employed in archaeology in an effort to establish “best practices” for this new method. We focus on the integration of photogrammetry within a comprehensible research plan, the selection of equipment, the appropriate apportionment of labor and time on site, and a rubric for site photography that is conducive to successful and efficient modeling. We conclude that photogrammetric modeling will soon become an indispensable tool in most archaeological applications but should always be implemented in ways that do not place undue burdens on project personnel and budgets and that aid research goals in well-defined ways.
... In this way, a great number of published articles focused on small-scale buildings. Koutsoudis et al. [12] analysed a museum artefact: A replica of a Cycladic female figurine. Riveiro et al. [13] used historical masonry bridge arches as 3D geometric models. ...
... The study of divergent photographic shots is related to the study of interior spaces. Thus, Ding et al. [33] proposed Symmetry 2020, 12,1981 3 of 25 a hierarchical 3D reconstruction method which used disordered images taken by mobile phones. The improvements in the semantic segmentation by object labelling were the main contribution of these authors. ...
... From the analysis of a small statue, Kersten and Lindstaedt [36] found that there are not significant differences in the number of points and triangles in the models. Koutsoudis et al. [12] proved that high-quality models can be obtained from a large set of images under suitable light conditions and software. Here, Photoscan was used to compare the mesh with the point cloud, from which an error of 20 mm at 7 m was calculated, where 7 m was the largest distance studied by these researchers. ...
Article
Full-text available
The digitisation of architectural heritage has experienced a great development of low-cost and high-definition data capture technologies, thus enabling the accurate and effective modelling of complex heritage assets. Accordingly, research has identified the best methods to survey historic buildings, but the suitability of Structure-from-Motion/Multi-view-Stereo (SfM/MVS) for interior square symmetrical architectural spaces is unexplored. In contrast to the traditional SfM surveying for which the camera surrounds the object, the photograph collection approach is divergent in courtyards. This paper evaluates the accuracy of SfM point clouds against Terrestrial Laser Scanning (TLS) for these large architectural spaces with a symmetrical configuration, with the main courtyard of Casa de Pilatos in Seville, Spain, as a case study. Two different SfM surveys were conducted: (1) Without control points, and (2) referenced using a total station. The first survey yielded unacceptable results: A standard deviation of 0.0576 m was achieved in the northwest sector of the case study, mainly because of the difficulty of aligning the SfM and TLS data due to the way they are produced. This value could be admissible depending on the purpose of the photogrammetric model.
... They are more advantageous in terms of speed and accuracy [3]. Thanks to these advantages, medical [4,5], food [6], agriculture [7,8], security [9,10], architecture [11], production [12,13], and quality control [14]. In this study, the recommended machine vision system for real-time product quality control is used. ...
... Int J Adv Manuf Technol (2018) 96:[11][12][13][14][15][16][17][18][19] Content courtesy of Springer Nature, terms of use apply. Rights reserved. ...
Article
Full-text available
Machine vision systems provide significant advantages when compared to conventional methods. Inspired from this idea, a visual inspected system that is independent of dust and dirt is presented for glass production systems. The method consists of a camera, a conveyor system, and an image segmentation method. Architecture of proposed system is as follows: a specific area of the conveyor is isolated from the outside. When glass enters this area, defect inspection process begins. In the inspection process, damaged and undamaged regions on glass surface are segmented. Gabor filter is very effective to detect orientation and thickness of these defects. But, Gabor filter bank should be created using appropriate Gabor coefficients for real-time applications. Otherwise, the processing time will be too long or fail results will be obtained. For this purpose, a new Gabor filter bank is created using gray wolf optimizer. In the hardware section, light beams are injected into the glass and the movements of these beams are observed to increase the perceptibility of the damage. Beam distribution is homogenous in the undamaged regions, but homogeneity is disturbed in defected areas. To avoid irregular glare on the glass surface, external lights are blocked and an artificial light source is used. Artificial light beams are injected into perpendicularly in the glass. So, homogeneous illumination in the glass can be occurred. Finally, optimized Gabor filter bank is applied to glass images. Proposed system detects all defects on the glass surface in the experiments. Size of the smallest defect is 0.4 mm. Defect detection performance of proposed system is nearly 100%. If it is evaluated in terms of shape and size, accuracy rate is 98.1%.
... Many studies have evaluated the accuracy of photogrammetric models by comparison to data acquired by more established means of recording, such as by total station, physical measurement, and laser/structured light scanning (Douglass et al. 2015;Green et al. 2014;Koutsoudis et al. 2014Koutsoudis et al. , 2013Magnani and Schroder 2015;Magnani et al. 2016;Nocerino et al. 2014;Sanz et al. 2010;Sapirstein 2016). The error range observed is a consequence of the protocols used in image acquisition and model building as well as the scale of the object, the number of control points used, and the total area captured in each photograph (McCarthy 2014). ...
... The camera used was a pre-calibrated Nikon D5200 with an 18-140 mm lens. Although a fixed lens is preferable for photogrammetry, zoom lenses are commonly used in archaeological applications of SfM techniques (De Reu et al. 2013Doneus et al. 2011;Koutsoudis et al. 2013Koutsoudis et al. , 2014. The photos were taken with a constant aperture f/8, ISO (International Standards Organization) sensor setting of 200, and focal length 18 mm; settings determined according to the lighting conditions at the site. ...
Article
Full-text available
While photogrammetry has become popular in archaeology and heritage management as an effective, low-cost method for generating detailed three-dimensional models, it remains to be established that the accuracy of model-derived measurements is sufficient for analytical purposes. Based on an expedient, in-field model processing protocol, we report preliminary results concerning the accuracy of artifact provenience information derived from photogrammetry models of excavation surfaces at the Upper Palaeolithic site of Shuidonggou Locality 2 in China. Error in model-derived provenience can range easily into the centimeter scale; accuracy in some spatial axes are significantly, but weakly, affected by the size of the sampled surface. While the observed error range is larger than thresholds proposed for Palaeolithic excavations, it is arguably acceptable in settings where the analytical demand for provenience precision is lower. We identify possible sources of error and discuss how model accuracy can be improved by additional systematic testing.
... Pre-processing can enhance image features that are important for the 3D reconstruction by improving local image feature contrast using a Wallis filter (Barazzetti et al., 2010;Remondino et al., 2016) or reducing noise with an adaptive smoothing filter (Remondino and El-Hakim, 2006;Barazzetti et al., 2010). Another widely explored pre-process is to mask out the background or non-essential features (Barazzetti et al., 2010;Koutsoudis et al., 2013;Gallo et al., 2014;Guidi et al., 2014;Troisi et al., 2015;Abate et al., 2016;Marziali and Dionisio, 2017;Sapirstein and Murray, 2017). These studies report improvements in alignment quality (Abate et al., 2016) and decreases in reconstruction processing times up to 75% (Koutsoudis et al., 2013;Gallo et al., 2014;Troisi et al., 2015). ...
... Another widely explored pre-process is to mask out the background or non-essential features (Barazzetti et al., 2010;Koutsoudis et al., 2013;Gallo et al., 2014;Guidi et al., 2014;Troisi et al., 2015;Abate et al., 2016;Marziali and Dionisio, 2017;Sapirstein and Murray, 2017). These studies report improvements in alignment quality (Abate et al., 2016) and decreases in reconstruction processing times up to 75% (Koutsoudis et al., 2013;Gallo et al., 2014;Troisi et al., 2015). Background masking methods have included masking directly in the Agisoft 3D reconstruction software or using external image processing software like Photoshop (Porter et al., 2016;Marziali and Dionisio, 2017). ...
Conference Paper
Image-based 3D reconstruction processing tools assume sharp focus across the entire object being imaged, but depth of field (DOF) can be a limitation when imaging small to medium sized objects resulting in variation in image sharpness with range from the camera. While DOF is well understood in the context of photographic imaging and it is considered with the acquisition for image-based 3D reconstruction, an "acceptable" level of sharpness and associated "circle of confusion" has not yet been quantified for the 3D case. The work described in this paper contributes to the understanding and quantification of acceptable sharpness by providing evidence of the influence of DOF on the 3D reconstruction of small to medium sized museum objects. Spatial frequency analysis using established collections photography imaging guidelines and targets is used to connect input image quality with 3D reconstruction output quality. Combining quantitative spatial frequency analysis with metrics from a series of comparative 3D reconstructions provides insights into the connection between DOF and output model quality. Lab-based quantification of DOF is used to investigate the influence of sharpness on the output 3D reconstruction to better understand the effects of lens aperture, camera to object surface angle, and taking distance. The outcome provides evidence of the role of DOF in image-based 3D reconstruction and it is briefly presented how masks derived from image content and depth maps can be used to remove unsharp image content and optimise structure from motion (SfM) and multiview stereo (MVS) workflows.
... Pre-processing can enhance image features that are important for the 3D reconstruction by improving local image feature contrast using a Wallis filter (Barazzetti et al., 2010;Remondino et al., 2016) or reducing noise with an adaptive smoothing filter (Remondino and El-Hakim, 2006;Barazzetti et al., 2010). Another widely explored pre-process is to mask out the background or non-essential features (Barazzetti et al., 2010;Koutsoudis et al., 2013;Gallo et al., 2014;Guidi et al., 2014;Troisi et al., 2015;Abate et al., 2016;Marziali and Dionisio, 2017;Sapirstein and Murray, 2017). These studies report improvements in alignment quality (Abate et al., 2016) and decreases in reconstruction processing times up to 75% (Koutsoudis et al., 2013;Gallo et al., 2014;Troisi et al., 2015). ...
... Another widely explored pre-process is to mask out the background or non-essential features (Barazzetti et al., 2010;Koutsoudis et al., 2013;Gallo et al., 2014;Guidi et al., 2014;Troisi et al., 2015;Abate et al., 2016;Marziali and Dionisio, 2017;Sapirstein and Murray, 2017). These studies report improvements in alignment quality (Abate et al., 2016) and decreases in reconstruction processing times up to 75% (Koutsoudis et al., 2013;Gallo et al., 2014;Troisi et al., 2015). Background masking methods have included masking directly in the Agisoft 3D reconstruction software or using external image processing software like Photoshop (Porter et al., 2016;Marziali and Dionisio, 2017). ...
Article
Full-text available
Image-based 3D reconstruction processing tools assume sharp focus across the entire object being imaged, but depth of field (DOF) can be a limitation when imaging small to medium sized objects resulting in variation in image sharpness with range from the camera. While DOF is well understood in the context of photographic imaging and it is considered with the acquisition for image-based 3D reconstruction, an “acceptable” level of sharpness and associated “circle of confusion” has not yet been quantified for the 3D case. The work described in this paper contributes to the understanding and quantification of acceptable sharpness by providing evidence of the influence of DOF on the 3D reconstruction of small to medium sized museum objects. Spatial frequency analysis using established collections photography imaging guidelines and targets is used to connect input image quality with 3D reconstruction output quality. Combining quantitative spatial frequency analysis with metrics from a series of comparative 3D reconstructions provides insights into the connection between DOF and output model quality. Lab-based quantification of DOF is used to investigate the influence of sharpness on the output 3D reconstruction to better understand the effects of lens aperture, camera to object surface angle, and taking distance. The outcome provides evidence of the role of DOF in image-based 3D reconstruction and it is briefly presented how masks derived from image content and depth maps can be used to remove unsharp image content and optimise structure from motion (SfM) and multiview stereo (MVS) workflows.
... Once we had executed the GNSS and photogrammetric survey, the SFM (Structure from Motion) algorithm was used for the construction of the point clouds of the indoor and outdoor environments. This technology allows the reconstruction of the point cloud using a dataset of photos that captures the surfaces from different points of view [8]. Indeed, with the recent achievements in computer and information technologies, traditional procedures for survey operations have been increasingly At the same time, a multi-image photogrammetric survey of every room was acquired for the reconstruction of the indoor environments. ...
... Once we had executed the GNSS and photogrammetric survey, the SFM (Structure from Motion) algorithm was used for the construction of the point clouds of the indoor and outdoor environments. This technology allows the reconstruction of the point cloud using a dataset of photos that captures the surfaces from different points of view [8]. Indeed, with the recent achievements in computer and information technologies, traditional procedures for survey operations have been increasingly replaced with digital close-range photogrammetry [9]. ...
Article
Full-text available
The latest results obtained through photogrammetric restitution enhanced by GNSS (Global Navigation Satellite System) RTK (Real-Time Kinematic) survey achieved increased levels of accuracy. These survey solutions are used to rapidly obtain a detailed model with an excellent level of accuracy (centimetric) with cheaper equipment. However, the contour conditions are not always favorable for obtaining the best results in a simple way. The work presented in this paper shows the survey and the photogrammetric restitution of the Manfredonic Castle of Mussomeli in Sicily, developed as a part of the PON NEPTIS European Project, aimed at the valorization of Cultural Heritage (CH). This case is a typical example of a complex survey carried out in an impervious environment where traditional survey procedures are totally useless or require a longer amount of time and great effort if a high level of accuracy is requested. In this case, considering the natural conditions of the site, the only way to perform the task has been the use of photogrammetric restitution based on UAV (unmanned aerial vehicle) technologies and GNSS survey. The precision obtained from the results allowed us to create a geometric 3D reconstruction of the monumental complex of the castle for the valorization of the site, which was the main goal of the whole process. The procedure that is the focus of this work is a test of rapid 3D CH survey and documentation in an impervious environment.
... The software can rapidly produce clean 3D surface meshes with high-resolution photographic textures, making PG an increasingly appealing alternative to laser-scanning (e.g. Koutsoudis et al. 2013, McCarthy 2014. ...
... Still, the potential for automated PG demonstrated in the laboratory has yet to be fully realized in practice. While errors below 1 mm have been established in controlled conditions (Jennings and Black 2012, Koutsoudis et al. 2013, Remondino et al. 2009, measurement mistakes on the order of 5-10 cm are typical in automated PG projects at buildings and sites (Bhatla et al. 2012, Dai and Lu 2010, Doneus et al. 2011, Klein el al. 2012, Sahin et al. 2012. A standard error of about 1 cm has been reported in a few applications at the trenchand building-scale, implying mistakes in the 1-5 cm range would occur in these datasets (De Reu et al. 2013, De Reu et al. 2014, Dellepiane et al. 2013, Kertsen & Lindstaedt 2012, Koutsoudis et al. 2014, Olson et al. 2013, Riveiro et al. 2011. ...
Chapter
Full-text available
The Digital Architecture Project (DAP) produces 3D models and reconstructed visualizations of archaic Greek temples. Its recent photogrammetric survey of the temple of Hera at Olympia, the earliest well-preserved Doric structure in Greece, resulted in a high-resolution 3D model for the ca. 20x50 m structure. The linear measurement accuracy has been determined to be as high as ± 1 mm locally, and ± 10 mm globally (95% CI). The analysis of the visualizations has already provided valuable insight into the temple’s architectural history. In order to manage the large amount of data, the models have been rendered in 2D layers corresponding to conventional state plans and elevations. The DAP proposes a virtual museum for disseminating this resource. Το Digital Architecture Project (DAP) δημιουργεί μοντέλα τριών διαστάσεων και ψηφιακές αναπαραστάσεις Αρχαϊκών ελληνικών ναών. Πρόσφατη φωτογραμμετρική έρευνα του ναού της Ήρας στην Ολυμπία, του αρχαιότερου και καλύτερα διατηρημένου οικοδόμηματος Δωρικού ρυθμού στην Ελλάδα, οδήγησε στην κατασκευή ένος τριδιάστατου μοντέλου υψηλής ανάλυσης για το οικοδόμημα (διαστάσεων 20x50 μ περίπου). Η γραμμική ακρίβεια μέτρησης έχει καθοριστεί στο ± 1 χλστ. σε τοπικό επίπεδο, και στα ± 10 χλστ. σε παγκόσμιο επίπεδο (95% CI). Η ανάλυση των οπτικοποιήσεων έχει ήδη δώσει σημαντικά στοιχεία για την αρχιτεκτονική ιστορία του ναού. Για τη διαχείριση του μεγάλου όγκου των δεδομένων, τα μοντέλα έχουν αποδοθεί σε επίπεδα δύο διαστάσεων σε αντιστοιχία με τις συμβατικές κατόψεις και τομές. Το DAP προτείνει ένα ψηφιακό μουσείο για τη διάδοση αυτών των δεδομένων.
... The 3D models were generated using Agisoft PhotoScan, the software used in many archaeological projects (De Reu et al., 2013;Koutsoudis et al., 2013;Willis and Jalandoni, 2011). To test the graphic quality of the resulting 3D model as the basis to analyse details and to produce digital tracings, we will digitally record the same motif from a high-resolution photograph taken with a Canon D2X, and from an orthomosaic from the medium-quality model and the optimized model. ...
... However, the recent proliferation of digital cameras and free or reasonably priced processing software is contributing to the widespread use in archaeology (e.g. De Reu et al., 2013; Koutsoudis et al., 2013), as well as rock art research (e.g. Willis and Jalandoni, 2011). ...
Article
The discussion of digital photogrammetry and/or 3D laser scanning for recording the geometry of rock art sites is not new, but the production of high-quality 3D models requires great expenditure and specialized personnel that are not accessible to everyone or applicable to all sites. While the use of low-cost cameras and photogrammetry has been suggested as an alternative for fast visualization of rock art, do the results have enough quality for the metric and visual analysis of the art? This paper explores the potential of low-cost Structure-from-Motion (SfM) photogrammetry performed by non-professional surveyors, with no camera calibration and no tripod to speed the process, as an alternative cost-effective tool for quantitative and qualitative analysis of rock art. The innovative aspect of this paper is that we have verified the metric accuracy and graphic quality of low-cost 3D models and shown that they can be used as an effective low-cost tool for detailed analysis and tracing of rock art.
... The advantages of UAV remote sensing are not limited to low costs in the acquisition of high spatial resolution imagery, but also include the ability to produce surface models (e.g., DSMs, TINs, DTMs) from the same images [14,16,23]. UAVs also offer high spectral and temporal data resolutions [5,13], a high degree of automation in the process of image acquisition and processing [14,25,26], and less influence of specific weather conditions, such as the presence of clouds that affect data collection from manned aircrafts and satellite imagery [22,27]. Moreover, many advantages of UAV imagery are related to recent developments in computer vision-based algorithms for processing. ...
Article
Full-text available
Physical Habitat Assessments (PHA) are useful to characterize and monitor stream and river habitat conditions, but can be costly and time-consuming. Alternative methods for data collection are getting attention, such as Unmanned Aerial Vehicles (UAV). The objective of this work was to evaluate the accuracy of UAV-based remote sensing techniques relative to ground-based PHA measurements, and to determine the influence of flight altitude on those accuracies. A UAV quadcopter equipped with an RGB camera was flown at the altitudes of 30.5 m, 61.0 m, 91.5 m and 122.0 m, and the metrics wetted width (Ww), bankfull width (Wbf) and distance to water (Dw) were compared to field PHA. The UAV-PHA method generated similar values to observed PHA values, but underestimated distance to water, and overestimated wetted width. Bankfull width provided the largest RMSE (25-28%). No systematic error patterns were observed considering the different flight altitudes, and results indicated that all flight altitudes investigated can be reliably used for PHA measurements. However, UAV flight at 61 m provided the most accurate results (CI = 0.05) considering all metrics. All UAV parameters over all altitudes showed significant correlation with observed PHA data, validating the use of UAV-based remote sensing for PHA.
... Twenty-one scale bars were used to scale the model to millimetre accuracy. Low-cost structure-from-motion (SfM) 3D modelling is increasingly accepted and utilised in archaeology and particularly rock art research(Chandler and Fryer 2005;Chandler et al. 2007;Sevara and Goldhahn 2011;Willis and Jalandoni 2011;De Reu et al. 2013;Koutsoudis et al. 2013;Plisson and Zotkina 2015;Fritz et al. 2016;Willis et al. 2016;Burton et al. 2017). ...
Article
Full-text available
The rock art of Angono is the most famous and controversial rock art site in the Philippines. It has been 50 years since the rock art was discovered, studied and interpreted. This paper identifies two phases of rock art production and uses 3D modelling and Geographic Information System (GIS) enhancements to corroborate the interpretation. Furthermore, by digitally tracing the figures we have produced a more accurate and complete record of the rock art. The digital record allows for statistical descriptions and interpretations previously not available, as well as providing a baseline for monitoring the rock art at the site. © 2018 Australian Rock Art Research Association. All rights reserved.
... La ricostruzione tridimensionale del manufatto è stata ottenuta mediante il software Agisoft Photoscan, utilizzando la procedura denominata SFM (Structure for Motion). Questa tecnologia permette di ottenere una nuvola di punti dell'ambiente, a partire da un dasaset di immagini che catturano l'oggetto da diverse angolazioni (Koutsoudis et al. 2013). Per ottenere la nuvola di punti correttamente georiferita e scalata, sono stati importati all'interno del software i target naturali rilevati con l'ausilio del ricevitore satellitare GNSS. ...
Conference Paper
Full-text available
RIASSUNTO La più recente innovazione nel campo della fotogrammetria digitale ha portato a cambiamenti sostanziali rispetto alle metodologie di rilievo tradizionali. Queste tecnologie, affiancate allo sviluppo di sistemi di posizionamento satellitare GNSS sempre più accurati, hanno permesso di ottenere livelli di precisione sempre più elevati, soprattutto quando si opera in condizioni ottimali. Molto spesso, le condizioni operative reali durante l'esecuzione di un rilievo presentano delle complicazioni, in relazione alle condizioni atmosferiche, alla morfologia del terreno, al tempo ed alle risorse disponibili ed alla complessità dell'oggetto da rilevare, fattori tutti che contribuiscono a ridurre la qualità dei risultati attesi. Si ritiene di interesse, pertanto, illustrare il rilievo di un complesso monumentale molto esteso e la successiva restituzione tridimensionale realizzati per finalità di valorizzazione del bene, attività condotte in un tempo molto limitato, con esigue risorse umane e in condizioni di complessità operativa. Oggetto di indagine è stato il Castello Manfredonico di Mussomeli, un'imponente struttura medievale posizionata su un masso roccioso che si erge a strapiombo sulle colline circostanti. Il rilievo del castello, inespugnato nel corso dei secoli grazie alla sua posizione, ha comportato difficoltà esecutive dovute alla irraggiungibilità di alcune molte parti e più in generale alla complessità morfologica dell'area circostante, all'elevato dislivello tra le parti, alle condizioni atmosferiche generali e microclimatiche nell'intorno ristretto-come la presenza di forti correnti d'aria e vortici in prossimità delle pareti del masso di roccia-tutti aspetti che hanno condizionato il risultato finale. Il livello di precisione ottenuto è stato comunque sufficiente per garantire la ricostruzione geometrica di un modello 3D, ed ha permesso di migliorare la conoscenza del bene sotto l'aspetto geometrico permettendo l'ulteriore sviluppo di attività per valorizzazione in modalità virtuale. Il lavoro è stato sviluppato all'interno del Progetto Europeo PON NEPTIS, finalizzato alla valorizzazione del patrimonio culturale attraverso l'utilizzo e la sperimentazione di nuove tecnologie informatiche. ABSTRACT The most recent innovation on digital photogrammetry has led to substantial changes compared to traditional survey methodologies. These technologies, alongside the development of increasingly accurate GNSS satellite positioning systems, have been able to achieve higher levels of precision, at a reduced cost, specially working in perfect conditions. Indeed, real working conditions during survey operations led often troubles, due to weather, morphology of the terrain, time, resources available and the complexity of the object to survey; all these factors contributed to the reduction of the quality of expected results. Therefore, it's considered object of interest to illustrate the survey of a very large monumental complex and the next 3D restitution, developed for the valorization of the good, timeless activities carried out with few human resources and complex working conditions. The object of the survey has been the Manfredonic Castle of Mussomeli, a large medieval structure built on a massive large rock that rises overhanging the surrounding hills. The survey of the castle, unconquered over the centuries thanks to the position, has been characterized by executive difficulties caused by the presence of inaccessible environments and, generally, the morphological complexity of the surrounding area, high difference in elevation between the parts, general atmospheric and microclimatic conditions in the restricted area-as the presence of strong currents of air and vortices near the walls of the rock-, all aspects that have affected the final result. The level of precision obtained was sufficient to guarantee the geometric reconstruction of a 3D model, allowing to improve the knowledge of the good under the geometric aspect for the further development of activities for the virtual valorization. The work has been developed within the PON NEPTIS European Project, aimed at enhancing the CH (Cultural Heritage) through the use and experimentation of new information technologies.
... This software is based on SFM-DMVR which is a fusion of so called SFM and DMVR methods. The software is enable to generate 3D models using the disparity map fusion [31,32]. Not much information is available about the internal matching algorithms implemented in Agisoft Due to commercial precautions. ...
Article
Three dimensional modelling of the objects is one the most discussed issues in Photogrammetry and Computer Vision. One of the factors affecting the accuracy of the obtained model in image-based methods is the software and algorithm to generate the model. Another important factor is the type of imaging sensor. Due to availability of cell phone sensors to the public, popularity of professional sensors and the advent of stereo sensors, a question raised about which imaging sensor can lead to more accurate and complete model. Although many research have been accomplished to identify a suitable software and algorithm to achieve an accurate and complete model, little attention has been paid to the type of imaging sensors and its effects on the quality of the final model. This paper aims to introduce an appropriate combination of a sensor and software to provide an accurate and complete model. To do this, different available software were compared and the most popular ones in each category were chosen. In this test, four small objects with distinct geometric properties were chosen and their accurate models as reliable true data were generated. Images were then captured using Fujifilm Real 3D stereo camera, Apple iPhone 5s and Nikon D3200 professional camera and three dimensional models of the objects were obtained using each of the software. Finally, a comprehensive comparison between the results showed that the best combination of software and sensors for generating three-dimensional models is directly related to the type of imaging sensors, the software and object shape. Generally better quantitative and qualitative results were obtained by using the Nikon D3200 professional camera.
... The effectiveness of low-cost 3D modeling is well documented in archaeology (Chandler & Fryer, 2005;Chandler, Bryan, & Fryer, 2007;De Reu et al., 2013;Sevara & Goldhahn, 2011;Koutsoudis, Vidmar, & Arnaoutoglou, 2013), and there are several examples of 3D models providing an accurate record of the rock art for analysis and preservation (Davis, Belton, Helmholz, Bourke, & McDonald, 2017;Fritz, Willis, & Tosello, 2016;Jalandoni et al., 2018;Willis & Jalandoni, 2011). ...
Article
Full-text available
Structure from motion (SfM) photogrammetry and geographic information system (GIS) tools were used to document an engraving site in Bontoc, Philippines. The natural discolorations of the rock obfuscated the engravings rendering traditional recording methods ineffective. Using a GIS software not only highlighted the engravings by applying an algorithm, but also allowed for a pioneering way to digitally trace and classify motifs, resulting in a spatially linked database. The digital tracings were also compared with manual tracings and proved to be more accurate. The database was then quantitatively analyzed for the seminal inventory of the rock art of Alab, Bontoc. This combination of SfM photogrammetry and GIS tools introduces a cost‐efficient method to effectively enhance, document, and analyze engraved rock art.
... A commercial implementation of the SfM-MVS was selected. Agisoft's Photo-Scan Professional has been used by the same research team on various digitization experiments that indicated that the tool can be used for photogrammetry projects (Koutsoudis et al. 2015;Koutsoudis et al. 2014;Koutsoudis et al. 2013). For the data collection phase, a pair of mirrorless DSLR cameras (Samsung NX1000) equipped with CMOS sensor (size: 23.5 × 15.7mm, effective resolution: 20.3 mega pixels out of 21.6 megapixels, pixel pitch: 4.26 μm) were used. ...
Book
Full-text available
The essays in this collection are transformative, moving beyond basic collaboration and skilfully contextualizing both scientic knowledge in the humanities and humanities knowledge in the sciences. Doing so not only heightens the quality of the research, but heightens understanding, redrawing traditional lines between disciplines and redening what it means to truly collaborate and to be a scholar in the digital age."-Bill Endres, University of Oklahoma In this unique collection the authors present a wide range of interdisciplinary methods to study, document, and conserve material cultural heritage. The methods used serve as exemplars of best practice with a wide variety of cultural heritage objects having been recorded, examined, and visualised. The objects range in date, scale, materials, and state of preservation and so pose dierent research questions and challenges for digitization, conservation, and ontological representation of knowledge. Heritage science and specialist digital technologies are presented in a way approachable by non-scientists, while a separate technical section provides details of methods and techniques, alongside examples of notable applications of spatial and spectral documentation of material cultural heritage, with selected literature and identication of future research.
... While there are previous works that recognize the possibilities of CRDP for certain applications [14] there has been little systematic study comparing its advantages over other 3D techniques. Mainly in terms of the most appropriate software, requirements, quality, cost and resolution [15][16][17][18][19][20][21][22]. As it was previously recognized, to adopt these techniques for accurate measurement purposes, clear accuracy statements, benchmarking and evaluations must be carried out [23]. ...
Article
As part of an ongoing program performed in collaboration with museums and institutions of Argentina, we present results on the application of laser based techniques and 3D imaging methods for material characterization, cleaning and documentation of cultural heritage objects, particularly the collections of public museums located in different regions of the country. In this work, we present results on the application of Laser Induced Breakdown Spectroscopy (LIBS) for material characterization of objects found in the ex-detention, torture and extermination center called Club Atletico (Instituto Espacio Memoria) of Buenos Aires. We also show laser cleaning applications to archaeological objects found in Patagonia and in the city of Buenos Aires. Finally, we present a 3D system developed for recording and documentation of artworks. It is based on digital photogrammetry and uses low cost devices and free software for data processing. This 3D system has measurement tools and the possibility of creating deterioration maps in the virtual model. We present examples of the applications of this 3D system to artworks from argentine museums.
... While there are previous works that recognize the possibilities of CRDP for certain applications [14] there has been little systematic study comparing its advantages over other 3D techniques. Mainly in terms of the most appropriate software, requirements, quality, cost and resolution [15][16][17][18][19][20][21][22]. As it was previously recognized, to adopt these techniques for accurate measurement purposes, clear accuracy statements, benchmarking and evaluations must be carried out [23]. ...
Article
Full-text available
As part of an ongoing program performed in collaboration with museums and institutions of Argentina, we present results on the application of laser based techniques and 3D imaging methods for material characterization, cleaning and documentation of cultural heritage objects, particularly the collections of public museums located in different regions of the country. In this work, we present results on the application of Laser Induced Breakdown Spectroscopy (LIBS) for material characterization of objects found in the ex-detention, torture and extermination center called Club Atletico (Instituto Espacio Memoria) of Buenos Aires. We also show laser cleaning applications to archaeological objects found in Patagonia and in the city of Buenos Aires. Finally, we present a 3D system developed for recording and documentation of artworks. It is based on digital photogrammetry and uses low cost devices and free software for data processing. This 3D system has measurement tools and the possibility of creating deterioration maps in the virtual model. We present examples of the applications of this 3D system to artworks from argentine museums.
... hotogrammetry and scanning.DeReu et al. (2012) andDoneus et al. (2011) evaluated SfM for the archaeological excavation documentation. Additionally, SfM has been examined as a practical digitization tool (McCarthy 2014). Researchers have also compared the data produced by different SfM implementations(Nguyen et al. 2012;Kersten and Lindstaedt 2012).Koutsoudis et al. (2013) evaluated the performance of an SfM implemen tation on movable objects and monuments. The data evaluation phase indicated ...
Chapter
Full-text available
For Digital Cultural Heritage, 3D modeling is an essential practice for the identification, monitoring, conservation, restoration, and enhancement of archaeological objects from artifacts to monuments. In this context 3D computer graphics can support archaeology and heritage policy, offering scholars a “sixth sense” for the understanding of the past, as it allows them to almost relive it. In addition, current trends for 3D video gaming (serious games) and scientific storytelling provide a variety of new approaches towards new, enhanced, and realistic experiences of the past. The research project “Digital Enterprise for Learning Practice of Heritage Initiative FOR Delphi” (Delphi4Delphi) targets most of these issues. In particular, it focuses on educational, research, and social implications of digital heritage, through the use of modern technologies such as digital optical documentation, geographical information systems and georeferencing, big data, video and interactive content production for education, virtual and augmented reality, cyber archaeometry, and Cyber-Archaeology. This chapter presents an overview of Delphi4Delphi in relation to the issues of acquisition, curation, and dissemination of spatial cultural heritage data.
... PhotoScan ( Brutto and Paola 2012;Verhoeven et al. 2013;Koutsoudis et al. 2013; Cerrillo-Cuenca and Marcela 2015) ...
Article
Evaluation and benchmarking of real-time skin detectors remain challenging because of multiple evaluation attributes that must be considered. Numerous evaluation and benchmarking techniques have been proposed, but they exhibit several limitations. Fixing multiple attributes based on benchmarking approaches by using other attributes limits reliable real-time skin detection. This paper presents comprehensive insights into the evaluation and benchmarking of real-time skin detectors on the basis of two critical directions. Current evaluation criteria highlight conflicting issues and benchmarking techniques to identify weak points, and possible solutions are discussed. The findings are as follows: (1) open issues and challenges to evaluation and benchmarking are emphasized; and (2) decision making using multiple criteria such as reliability, time complexity, and error rate within a dataset is used for evaluating and benchmarking real-time skin detectors to come up with solutions for future directions.
... The function computes the distances between each vertex of the point cloud to the nearest triangle of the mesh surface. This distance is calculated as follows: if the orthogonal projection of the vertex lies inside the surface defined by a triangle the distance between the vertex and its point-of-intersection on the surface is calculated; else the algorithms estimates the distance between the vertex and its projection to the nearest edge or vertex of the triangle (Koutsoudis et al. 2013). The BF and FS 3D models were used as point clouds whereas the reference 3D model was used as triangular mesh. ...
Article
Full-text available
The 3D digitisation of small artefacts is a very complicated procedure because of their complex morphological feature structures, concavities, rich decorations, high frequency of colour changes in texture, increased accuracy requirements etc. Image-based methods present a low cost, fast and effective alternative because laser scanning does not meet the accuracy requirements in general. A shallow Depth of Field (DoF) affects the image-based 3D reconstruction and especially the point matching procedure. This is visible not only in the total number of corresponding points but also in the resolution of the produced 3D model. The extension of the DoF is a very important task that should be incorporated in the data collection to attain a better quality of the image set and a better 3D model. An extension of the DoF can be achieved with many methods and especially with the use of the focus stacking technique. In this paper, the focus stacking technique was tested in a real-world experiment to digitise a museum artefact in 3D. The experiment conditions include the use of a full frame camera equipped with a normal lens (50mm), with the camera being placed close to the object. The artefact has already been digitised with a structured light system and that model served as the reference model in which 3D models were compared and the results were presented.
... Despite the low cost and time consuming aspect, SfM is found to have more flexiblility to capture the data at a various range of spatial scale. TLS has a range detection distance between 1 meter to 500 meters, which is very suitable for detail site investigation, while ALS is commonly used for wider study sites [18] SfM can be used to construct 3D models at sub-meters scale and up to areas about tens of kilometres square [5]. Therefore, the implementation of SfM is highly recommended in poor data area such as study area. ...
Conference Paper
Full-text available
Adequate knowledge of geological structure is an essential for most studies in geoscience, mineral exploration, geohazard and disaster management. The geological map is still one the datasets the most commonly used to obtain information about the geological structure such as fault, joint, fold, and unconformities, however in rural areas such as Central Java data is still sparse. Recent progress in data acquisition technologies and computing have increased the interest in how to capture the high-resolution geological data effectively and for a relatively low cost. Some methods such as Airborne Laser Scanning (ALS), Terrestrial Laser Scanning (TLS), and Unmanned Aerial Vehicles (UAVs) have been widely used to obtain this information, however, these methods need a significant investment in hardware, software, and time. Resolving some of those issues, the photogrammetric method structure from motion (SfM) is an image-based method, which can provide solutions equivalent to laser technologies for a relatively low-cost with minimal time, specialization and financial investment. Using SfM photogrammetry, it is possible to generate high resolution 3D images rock surfaces and outcrops, in order to improve the geological understanding of Indonesia. In the present contribution, it is shown that the information about fault and joint can be obtained at high-resolution and in a shorter time than with the conventional grid mapping and remotely sensed topographic surveying. The SfM method produces a point-cloud through image matching and computing. This task can be run with opensource or commercial image processing and 3D reconstruction software. As the point cloud has 3D information as well as RGB values, it allows for further analysis such as DEM extraction and image orthorectification processes. The present paper describes some examples of SfM to identify the fault in the outcrops and also highlight the future possibilities in terms of earthquake hazard assessment, based on fieldwork in the South of Yogyakarta City.
... mm [39,40]. Fewer tests have been tried with very small objects, though Koutsoudis et al. [41] modeled a 20 cm-tall Early Cycladic figurine with APG and an optical scanner, finding correspondences within 0.1 mm. A comparison of APG and scanned models of five crania had similar results [42]. ...
Article
Full-text available
Archaeologists, preservationists, and many other researchers have increasingly turned to photogrammetry as an alternative to optical 3D-scanning hardware. The technology is sufficiently new that researchers have only begun to establish the protocols and standards. This article presents a simple yet rigorously controlled method for 3D modeling small artifacts ca. 5-10. cm across. The specimen is rotated on a turntable to facilitate photography, and artificial lighting creates an even illumination throughout the resulting models. A masking technique allows a full 360° view of the object to be restored simultaneously, eliminating the need for aligning and merging partial scans or other post-processing. Repeatability tests of the resulting models indicate high precisions and accuracies that exceed those reported previously for photogrammetric modeling in the literature. The method can match the accuracy typically attained by commercial optical scanning systems.
... The reconstruction process of the PG method and its accuracy and precision depend on several technical factors, including camera equipment and software, as has been discussed elsewhere (Koutsoudis et al., 2013(Koutsoudis et al., , 2014De Reu et al., 2013;Wenzel et al., 2013). In our case, natural factors and environmental conditions may be more important for a successful and accurate digital reconstruction. ...
Article
Full-text available
Termite mounds (TMs) mediate biogeochemical processes with global relevance, such as turnover of the important greenhouse gas methane (CH4). However, the complex internal and external morphology of TMs impede an accurate quantitative description. Here we present two novel field methods, photogrammetry (PG) and cross-sectional image analysis, to quantify TM external and internal mound structure of 29 TMs of three termite species. Photogrammetry was used to measure epigeal volume (VE), surface area (AE) and mound basal area (AB) by reconstructing 3-D models from digital photographs, and compared against a water-displacement method and the conventional approach of approximating TMs by simple geometric shapes. To describe TM internal structure, we introduce TM macro- and micro-porosity (θM and θμ), the volume fractions of macroscopic chambers, and microscopic pores in the wall material, respectively. Macro-porosity was estimated using image analysis of single TM cross sections, and compared against full X-ray computer tomography (CT) scans of 17 TMs. For these TMs we present complete pore fractions to assess species-specific differences in internal structure. The PG method yielded VE nearly identical to a water-displacement method, while approximation of TMs by simple geometric shapes led to errors of 4–200 %. Likewise, using PG substantially improved the accuracy of CH4 emission estimates by 10–50 %. Comprehensive CT scanning revealed that investigated TMs have species-specific ranges of θM and θμ, but similar total porosity. Image analysis of single TM cross sections produced good estimates of θM for species with thick walls and evenly distributed chambers. The new image-based methods allow rapid and accurate quantitative characterisation of TMs to answer ecological, physiological and biogeochemical questions. The PG method should be applied when measuring greenhouse-gas emissions from TMs to avoid large errors from inadequate shape approximations.
... Nevertheless, the recent development of advanced image processing techniques opens new possibilities for CRDP for recording objects in a simpler way, with the quality and resolution of scanning techniques. While there are previous works that recognize the possibilities of CRDP for certain applications [21], there has been little systematic study comparing its advantages over other 3D techniques, mainly in terms of the most appropriate software, requirements, quality, cost and resolution [22][23][24][25][26][27][28][29]. As it was previously recognized, to adopt these techniques for accurate measurement purposes, clear accuracy statements, benchmarking and evaluations must be carried out [30]. ...
Article
Full-text available
3D image recording has reached an increasing impact on the field of cultural heritage. Applications include documentation of the state of conservation and dimensions of an object, the archaeological survey of artefacts, the dissemination of museum collections and sites, and packaging designing, among others. The 3D image acquisition techniques most commonly used are laser or structured light scanning and, increasingly, close range digital photogrammetry. In this work a 3D digitization case-study is presented in order to explore the advantages and possibilities of close range digital photogrammetry respect to scanning techniques in documentation of heritage objects. Free and low-cost software used by these techniques were tested and the quality of the resultsobtained in each case is analyzed. The potentiality of close range digital photogrammetry to enhance the resolution of the 3D recording is also discussed.
... hotogrammetry and scanning.DeReu et al. (2012) andDoneus et al. (2011) evaluated SfM for the archaeological excavation documentation. Additionally, SfM has been examined as a practical digitization tool (McCarthy 2014). Researchers have also compared the data produced by different SfM implementations(Nguyen et al. 2012;Kersten and Lindstaedt 2012).Koutsoudis et al. (2013) evaluated the performance of an SfM implemen tation on movable objects and monuments. The data evaluation phase indicated ...
... To do this work, 417 images were taken with resolution set to 1064 x 659 pixels. The images were taken from different viewpoints surrounding the case study, as suggested by Koutsoudis (Koutsoudis 2013) and with some approximation to capture as much details as possible. This survey helped us to gain some basic understanding of the site, permitting us to plan short but effective site visits for information-gathering in the real environment, needed to build more accurate models. ...
Conference Paper
Full-text available
The Brazilian favelas are a kind of informal settlements characterized by steep topography and a maze-like structure. Like many other settlements of its kind that are prevalent in developing countries today, they are often considered a problem rather than a solution. This paper is part of a larger research that taking a realistic stand aims to understand the formal structure of this city-shaping force and capture it into a rule-based, computational model. The goal is to develop appropriate requalifying procedures to intervene in informal settlements and guidelines for designing formal settlements in similar sites. The paper is focused on the use of digital technologies to reconstruct in 3D a favela used as a case study, a preliminary step to understand its formal structure and create a computational model.
... Discamps et al. 2016 ;Falkingham, Bates et Farlow 2014 ;Grün, Remondino et Zhang 2004), la visualisation de statues ou d'objets (e.g. Barreau et al. 2014 ;Kersten et Lindstaedt 2012 ;Koutsoudis, Vidmar et Arnaoutoglou 2013 ;Porter, Roussel et Soressi 2016 ;Sumner et Riddle 2008), et plus récemment la réalisation de modèles 3D d'éléments squelettiques (crânes, dents, os longs, etc.). ...
... The effectiveness of low-cost 3D modeling is well documented in archaeology (Chandler & Fryer, 2005;Chandler, Bryan, & Fryer, 2007;De Reu et al., 2013;Sevara & Goldhahn, 2011;Koutsoudis, Vidmar, & Arnaoutoglou, 2013), and there are several examples of 3D models providing an accurate record of the rock art for analysis and preservation (Davis, Belton, Helmholz, Bourke, & McDonald, 2017;Fritz, Willis, & Tosello, 2016;Jalandoni et al., 2018;Willis & Jalandoni, 2011). ...
Article
The cover image, by Andrea Jalandoni and Maria Kottermair, is based on the Research Article Rock art as microtopography, DOI: 10.1002/gea.21677.
... Ritz et al. (2011) developed a structured light system which employs a low-cost camera projector. Koutsoudis et al. (2013) used image-based modelling to 3D digitise a small Cycladic female figurine for evaluating the performance of commercial SfM-MVS software. The 3D model of two lekythoi was created with the use of a structured light system by XYZRGB consisting of two machine vision cameras for the determination of the geometry * Corresponding author of the artefact, a high-resolution camera for the texture and a DLP projector (Soile et al. 2013). ...
Article
Full-text available
In archaeological excavations, many small fragments or artefacts are revealed whose fine details sometimes should be captured in 3D. In general, 3D documentation methods fall into two main categories: Range-Based modelling and Image-Based modelling. In Range Based modelling, a laser scanner (Time of Flight, Structured light, etc.) is used for the raw data acquisition in order to create the 3D model of an object. The above method is accurate enough but is still very expensive in terms of equipment. On the other hand, Image-Based modelling, is affordable because the equipment required is merely a camera with the appropriate lens, and possibly a turntable and a tripod. In this case, the 3D model of an object is created by suitable processing of images which are taken around the object with a large overlap. In this paper, emphasis is given on the effectiveness of 3D models of frail archaeological finds originate from the palatial site of Ayios Vasileios in Laconia in the south-eastern Peloponnese, using low-cost equipment and methods. The 3D model is also produced using various, mainly freeware, hence low-cost, software and the results are compared to those from a well-established commercial one.
... Photogrammetry is now capable of generating models with high geometric detail at considerably lower cost than most optical scanning hardware. While the precision and accuracy of APG will vary with the skill of the photographer, preparation of the scene, photographic equipment, and processing techniques, it has become clear that competently generated APG models can meet the requirements for recording lapidary inscriptions (Ortiz Sanz et al. 2010;Kersten and Lindstaedt 2012;Koutsoudis et al. 2013;Lerma and Muir 2014;Sapirstein 2016;Sapirstein and Murray 2017). In fact, target-based APG surveys seem to exceed the accuracy of commonly used optical scanning hardware (Guidi et al. 2007;Slizewski et al. 2010;Counts et al. 2016;Sapirstein 2018). ...
Article
Full-text available
This article presents a new algorithm for the automated reconstruction and visualization of damaged ancient inscriptions. After reviewing current methods for enhancing incisions, a hybrid approach is adopted that combines advantages of 2D and 3D analytical techniques. A photogrammetric point cloud of an inscription is projected orthographically from an ideal vantage point, generating a 2.5D raster, including channels describing depth and surface derivatives. The next consideration is the obstacle to legibility posed by breaks in the ancient surface, which motivates the development of a new segmentation algorithm based on SLIC superpixels with region-merging adapted to operate on the geometry of the inscribed surface instead of color or intensity values. The algorithm classifies surface points by their likelihood of belonging to the uninscribed original plane, deliberate strokes, or breaks. Results are visualized in a manner suited for epigraphical analysis and publication through static images. Two case studies demonstrate the power and flexibility of this method, which has indicated changes to the reading of IG XIV 1, an early Greek text that has been debated for more than 150 years.
... Good quality free and open-source 3D reconstruction software has been developed in recent years (e.g. OpenMVG and PMVS [18,4]), but its performance cannot equal commercial software without complex and expert parametrisation [19,20,21,22]. This limits the usage of 3D reconstruction techniques to small, expert, and resourceful communities of practice. ...
Article
Full-text available
Sets of two dimensional images are insufficient to capture the development in time and space of three-dimensional structures. The 2D ‘flattening’ of photographs results in a significant loss of features especially if the photos were taken by one person. Automatically collecting and aligning photos in order to render 3D structures from 2D images without specialized equipment, is currently a complex process that requires specialist knowledge with often limited results. In this paper, an Open Science oriented workflow is proposed where an on-line file system is used to share photos of an object or an environment and to produce a virtual reality scene as a navigable 3D reconstruction that can be shared with other people. Our workflow is based on a distributed e-Infrastructure and overcomes common limitations of other approaches by having all the used technology integrated on the same platform and by not requiring specialist knowledge. A performance evaluation of the 3D reconstruction process embedded in the workflow is reported against a commercial software and an open-source software in terms of computational efficiency and reconstruction accuracy, and three marine science use cases are reported to show potential applications of the workflow.
Article
Every material and every surface has its own visual texture. Surfaces with monotone, repetitive or uniform visual texture represent a challenge for the image-based Structure From Motion Multi-View Stereo three-dimensional (3D) reconstruction method. It is possible to overcome the lack of visual texture on the surfaces by projecting synthetically generated images (patterns) using a video projector. This research proposes the generation of the synthetic images that are based on digits of irrational numbers pi, phi, e, sqrt2, sqrt3 and digits produced by the random number generator. Images were divided into three classes based on the number of hues. The aim is to evaluate synthetically generated images and determine the characteristics of the most suitable synthetic image(s) that increase the accuracy of the final reconstructed polygonal 3D model. The synthetically generated images were evaluated using results of the multi-criteria analysis as well as real and virtual planar surface 3D digitization methods, where images with uniform distribution histogram have the most suitable characteristics. To verify evaluation results, 3D reconstruction of aluminium test model was carried out. Four polygonal 3D models of the aluminium test model were reconstructed. Three polygonal 3D models were reconstructed using projected patterns of each class, and one was reconstructed in daylight condition. The resulting accuracies of reconstructed polygonal 3D models were evaluated using the Computer-Aided Inspection. The polygonal 3D model obtained by projecting class I pi I pattern with the strong random stochastic visual texture achieved std. distance of 0.173 mm and mean distance of 0.016 mm compared to the polygonal 3D model obtained in daylight condition with std. and mean distance of 1.188 mm and −0.139 mm respectively.
Article
Full-text available
The physical nature of cave walls and its impact on Upper Palaeolithic image making and viewing has frequently been invoked in explanations about the function of cave art. The morphological features (convexities, concavities, cracks and ridges) are frequently incorporated into the representations of prey animals that dominate the art, and several studies have attempted to document the relationship between the cave wall and the art in a quantitative manner. One of the effects of such incorporation is that undulating walls will distort the appearance of images as viewers change their viewing position. Was this distortion deliberate or accidental? Until now, the phenomenon has not been investigated quantitatively. We address this here, analysing 54 Late Upper Palaeolithic animal images deriving from three Cantabrian caves, Covalanas, El Pendo and El Castillo. We introduce a novel use for photogrammetry and 3D modelling through documenting the morphology of these caves' walls and establishing the specific relationship between the walls and the art created on them. Our observations suggest that Palaeolithic artists deliberately placed images on very specific topographies. The restricted nature of these choice decisions and the fact that the resulting distortions could have been avoided but were not suggest that the interaction between viewer, art and wall was integral to the way cave art functioned.
Chapter
In this unique collection the authors present a wide range of interdisciplinary methods to study, document, and conserve material cultural heritage. The methods used serve as exemplars of best practice with a wide variety of cultural heritage objects having been recorded, examined, and visualised. The objects range in date, scale, materials, and state of preservation and so pose different research questions and challenges for digitization, conservation, and ontological representation of knowledge. Heritage science and specialist digital technologies are presented in a way approachable to non-scientists, while a separate technical section provides details of methods and techniques, alongside examples of notable applications of spatial and spectral documentation of material cultural heritage, with selected literature and identification of future research. This book is an outcome of interdisciplinary research and debates conducted by the participants of the COST Action TD1201, Colour and Space in Cultural Heritage, 2012–16 and is an Open Access publication available under a CC BY-NC-ND licence.
Chapter
In this unique collection the authors present a wide range of interdisciplinary methods to study, document, and conserve material cultural heritage. The methods used serve as exemplars of best practice with a wide variety of cultural heritage objects having been recorded, examined, and visualised. The objects range in date, scale, materials, and state of preservation and so pose different research questions and challenges for digitization, conservation, and ontological representation of knowledge. Heritage science and specialist digital technologies are presented in a way approachable to non-scientists, while a separate technical section provides details of methods and techniques, alongside examples of notable applications of spatial and spectral documentation of material cultural heritage, with selected literature and identification of future research. This book is an outcome of interdisciplinary research and debates conducted by the participants of the COST Action TD1201, Colour and Space in Cultural Heritage, 2012–16 and is an Open Access publication available under a CC BY-NC-ND licence.
Book
Full-text available
Die Arbeitsgemeinschaft Computeranwendungen und Quantitative Methoden in der Archäologie (AD CAA) veranstaltet jährlich einen gleichnamigen Workshop, der 2013 an der Freien Universität Berlin stattfand. Die Aufsätze zeigen, dass dreidimensionale Daten bei der archäologischen Dokumentation und Analyse immer wichtiger werden. 3D-Modelle oder digitale Geländemodelle (DGMs) lassen sich mithilfe von photogrammetrischen Methoden (Structure-from-Motion) oder Laserscanning erstellen. Über die Dokumentation von Funden und Befunden hinaus erlauben solche Daten zum Beispiel die virtuelle Rekonstruktion von eingestürzten Mauern, die Mustererkennung auf Keilschrittafeln oder auch die Analyse der Beleuchtung im Innern eines griechischen Tempels. Archäologische Befunde werden in hochaufgelösten DGMs (Lidar- Daten) sichtbar. DGMs sind auch die Basis für Sichtbarkeitsanalysen und Berechnungen zur Wegerekonstruktion. Diese Publikation ausgewählter Beiträge zu aktuellen Dokumentations- und Analyseverfahren in den Altertumswissenschaften deckt einen weiten Bereich typischer CAA-Themen ab.
Article
Full-text available
Techniques for the three-dimensional digitization of tangible heritage are continuously updated, as regards active and passive sensors, data acquisition approaches, implemented algorithms and employed computational systems. These developments enable higher automation and processing velocities, increased accuracy, and precision for digitizing heritage assets. For large-scale applications, as for investigations on ancient remains, heritage objects, or architectural details, scanning and image-based modeling approaches have prevailed, due to reduced costs and processing durations, fast acquisition, and the reproducibility of workflows. This paper presents an updated metric comparison of common heritage digitization approaches, providing a thorough examination of sensors, capturing workflows, processing parameters involved, metric and radiometric results produced. A variety of photogrammetric software were evaluated (both commercial and open sourced), as well as photo-capturing equipment of various characteristics and prices, and scanners employing different technologies. The experimentations were performed on case studies of different geometrical and surface characteristics to thoroughly assess the implemented three-dimensional modeling pipelines.
Article
This paper describes the application of 3D digital technology to support the rebuild of lost decorative elements of an historical frame. The frame belongs to an 18th century painting depicting the portrait of D. José, Prince of Brazil, displayed at the National Palace of Queluz, Portugal. The application of digital technologies has been planned from the very beginning in order to avoid the traditional use of silicone in the reproduction of missing elements. The photogrammetric 3D acquisition, a non-contact methodology, has been used to reduce the manipulation and hence prevent further degradation of the artistic object. Following the 3D modelling operation, new decorative elements were made using an additive printing technology. In the final phase of the work, the post-printing treatment was carried out, in which aqueous products were used. 3D modelling, in addition to facilitate the restoration treatment of the historic frame, can also be useful in the creation of a digital collection of decorative frame elements, i.e. a virtual database.
Article
Imaging techniques inform the conservation, research, and understanding of museum collections. Two types of imaging techniques were examined in this study: infrared (IR) and three-dimensional (3D) imaging. Reflected IR imaging is well established as an investigative tool for conservation providing information about condition, materials, and manufacture beyond visible light documentation. Reflected IR imaging results in two-dimensional images, which are limited in how they represent 3D objects. Three-dimensional imaging techniques, such as white light scanning and photogrammetry, extend the possibilities of digitization by recording the geometry and texture of an object. Reflected IR imaging, photogrammetry, and white light scanning were used to document six objects from the Freud Museum and the Smithsonian National Museum of the American Indian. The present study provides examples of reflected IR imaging for enhanced detection of features of 3D cultural heritage objects; discusses the potential of integrating reflected IR and 3D imaging to more fully document features of 3D objects; and investigates two 3D imaging techniques, white light scanning and photogrammetry. The study assesses the two 3D imaging techniques, one more expensive and the other more accessible, to discover whether there is a significant difference in performance for the purpose of resolving the details recorded by reflected IR imaging. © 2017. Smithsonian Institution. Published by Informa UK trading as Taylor & Francis group
Chapter
We propose a workflow for cultural heritage applications where the fusion of 3D and 2D visual data is required. Using a metric 3D point cloud acquired by a Lidar scanner and 2D images of a commercial high-resolution DSLR camera, we show how to produce a high-quality, metric 3D model for documenting or architectural planning purpose. The proposed processing workflow describes the data acquisition tasks, the steps of the data processing, and the proposed method used for colorizing the point cloud from multiple cameras by choosing the camera with the best view based on different conditions. We show results on two Reformed churches.
Article
Full-text available
Structure from motion (SfM) mapping is a photogrammetric technique that offers a cost-effective means of creating three-dimensional (3-D) visual representations from overlapping digital photographs. The technique is now used more frequently to document the archaeological record. We demonstrate the utility of SfM by studying red scoria bodies known as pukao from Rapa Nui (Easter Island, Chile). We created 3-D images of 50 pukao that once adorned the massive statues ( moai ) of Rapa Nui and compare them to 13 additional pukao located in Puna Pau, the island's red scoria pukao quarry. Through SfM, we demonstrate that the majority of these bodies have petroglyphs and other surface features that are relevant to archaeological explanation and are currently at risk of continued degradation.
Article
Defocus blur in images deteriorates the quality of image-based textures for 3D archaeological models. We propose a method to estimate the defocus blur in calibrated multi-view images based on photographic optics. Our method estimates the defocus blur maps without any modification to cameras or using any statistical model of images. After the focus distance of each image is estimated from the reconstructed 3D models with physical scale, the near distance dn and the far distance df of acceptable sharpness from the view point are calculated. We set the colour of the model vertex to white if the vertex’s distance from the view point is within the interval between dn and df, otherwise black. Finally we render the 3D model into a defocus map using the intrinsic and extrinsic parameters of the camera. The obtained defocus maps can be utilized as masks to generate an all-focused texture map for the reconstructed 3D archaeological model. Experimental results on real data demonstrate the effectiveness of the method.
Article
While photogrammetry is widely implemented in fields such as archaeology and cultural heritage, the accuracy of this method has yet to be fully addressed. It is imperative that digital photogrammetry models depicting sites of cultural heritage have accurate dimensions to avoid misunderstandings and incorrect analysis. This paper outlines a new method for minimizing the adverse effects of bias and low repeatability precision in photogrammetry software. Specifically, this paper quantitatively addresses the effects of systematic error during scaling of digital photogrammetry models as well as the random error due to a repeatability issue inherent to photogrammetry software. The method was developed using statistical analysis and robust uncertainty calculations and validated through multiple case studies.
Article
The fragmentary nature of pottery is considered a common place. Conservators are requested to apply a proper restoration solution by taking under consideration a wide range of morphological features and physicochemical properties that derive from the artefact itself. In this work, the authors discuss on a low-cost pottery-oriented restoration pipeline that is based on the exploitation of technologies such as 3D digitisation, data analysis, processing and printing. The pipeline uses low-cost commercial and open source software tools and on the authors' previously published 3D pose normalisation algorithm that was initially designed for 3D vessel shape matching. The authors objectively evaluate the pipeline by applying it on two ancient Greek vessels of the Hellenistic period. The authors describe in detail the involved procedures such as the photogrammetric 3D digitisation, the 3D data analysis and processing, the 3D printing procedures and the synthetic shreds post processing. They quantify the pipeline's applicability and efficiency in terms of cost, knowledge overhead and other aspects related to restoration tasks.
Chapter
Full book chapter available at: https://www.researchgate.net/publication/322856067_An_Interdisciplinary_Discussion_of_the_Terminologies_used_in_Cultural_Heritage_Research
Chapter
Full book chapter available at: https://www.researchgate.net/publication/322696760_Beyond_Photography_An_interdisciplinary_exploratory_case_study_in_the_recording_and_examination_of_Roman_silver_coins
Chapter
Full-text available
A study was undertaken to record and examine silver coins believed to be ancient Roman in origin. The aim was to evaluate the suitability of various advanced, non-invasive optical and spectrometric techniques for analysing the physical characteristics and elemental composition of numismatic objects. The questions addressed included the characterization and authentication of test coins, as well as technical issues in the multimodal recording of material CH with metadata and paradata. The team investigated whether the methods chosen for this case study responded to the needs of numismatists, and whether they could feasibly be applied in museum practice, to support research and conservation of historic coins, and to enhance the documentation and dissemination of numismatic objects through heritage science.
Chapter
Full-text available
Accuracy, Artefact, Feature, Precision, Reconstruction, Resolution, Texture, Uncertainty are words central to many discussions of the documentation of Cultural Heritage. This chapter charts the interdisciplinary discussion towards a common understanding of terminologies used in CH. It is a discussion that recognizes critical differences or common misuse, and aims to contribute to a shared understanding that may be useful for all knowledge domains in the field.
Article
A peculiar characteristic of cultural heritage objects is their uniqueness. This results in an enormous importance for their preservation against aging, accidents, destruction etc. Although not replacing physical preservation, one way is the digitization of the objects in their current state by modern scanning technologies. This research describes a new method to combine 3D shape and color texture data acquired without contact to achieve high-resolution 3D representations. The method was basis of a portable 3D digitization system. The portable character allows its application on-site, which is essential for sensitive and non-transportable objects. A structured-light 3D sensor and a photo camera are used to capture the object from various overlapping perspectives. Then, the 3D shape and photographic data are processed and merged into a complete textured 3D model. Resolution and accuracy of the final model are in the range of 0.1 mm. Beyond preservation, the models can be used to make museum objects digitally available for experts or visitors worldwide e.g. in the form of online databases or virtual museums. A first utilization of the presented technology was realized with historic globes, especially with a Schöner globe dating from 1515 as highlight. The used method can be extended beyond RGB texture acquisition using multi-/hyperspectral sensors leading to an increased information content about the objects.
Article
Full-text available
3D models have become an essential part of many applications ranging from computer games to architectural design, virtual heritage, and visual impact studies. Traditionally, 3D model creation is done using modelling systems such as Maya or Blender. However, these systems have a steep learning curve and require a considerable amount of training to use. Thus, there is a critical need for tools which allow non-expert users to easily and efficiently create complex 3D scenes. To answer to that demand, a number of commercial image-based modelling packages have been introduced recently. Such software offers a very intuitive means to create 3D models from a sequence of images. However, the algorithms employed by these systems are usually kept secret, which makes it difficult to compare them algorithmically and identify common underlying concepts. This paper evaluates the most promising 3D reconstruction software packages with regard to efficiency, accuracy, limitations, constraints and compares them with a system developed by us in order to give an insight into their performance. To achieve that, we first describe our own 3D reconstruction system as a reference in order to make deductions about common concepts and differences. Then, we use a set of benchmark datasets to evaluate all considered systems, and gage their limitations with regard to the number of input images they need and the image resolution. Our evaluation shows that as the number of input images decreases, the geometry of models created using correspondence-based approaches contains more holes. However, the structure and geometry still reflect the original model. In contrast, silhouette-based methods produce coarse and distorted geometry as the number of input images decreases. Models obtained using silhouette-based methods from few input images are often unrecognizable.
Conference Paper
Full-text available
In most cases archaeological finds and objects remain in the country of origin. Thus, for potential users away from that location, 3D models of archaeological finds and objects form an increasingly important resource since they can be analysed and visualised in efficient databases using web-based tools over the Internet. Since typical 3D recording technologies for archaeological objects, such as terrestrial laser scanning or fringe projection systems, are still expensive, cumbersome, inconvenient, and often require expert knowledge, camera-based systems offer a cost-effective, simple and flexible alternative that can be immediately implemented. This paper will demonstrate how the geometry and texture of archaeological finds and objects can be automatically constructed, modelled and visualized from digital imagery using freely-available open-source software or web services. The results of several objects derived from different tested software packages and/or services are compared with reference data in order to analyse the accuracy and reliability of such objects.
Article
Full-text available
In archaeological Cultural Heritage study 3D modelling has become a very useful process to obtain indispensable data for documentation and visualization. Nowadays the continuous request to achieve photorealistic 3D models has led to testing different techniques and methodologies to speed up both data acquisition and the data processing phase. There are many examples of surveys conducted with the use of range-based and image-based techniques, but, in the last few years, the scientific research has been increasingly moving towards automatic procedures using Computer Vision approach to reduce time during data processing. Computer Vision approach offers a great opportunity for archaeological survey since it can be very easily used by existing Computer Vision interfaces such as 3D web services and open source or low cost software. The aim of this work is to evaluate the performance offered by Computer Vision interfaces for 3D survey of archaeological ruins using some 3D web-service tools and a low cost software like PhotoScan package. Some tests have been performed to analyze the geometric accuracy of 3D models obtained by 3D web-service tools and PhotoScan package through the comparison with a 3D model achieved by laser scanning survey.
Conference Paper
Full-text available
The recent developments in automated image processing for 3D reconstruction purposes have led to the diffusion of low-cost and open-source solutions which can be nowadays used by everyone to produce 3D models. The level of automation is so high that many solutions are black-boxes with poor repeatability and low reliability. The article presents an investigation of automated image orientation packages in order to clarify potentialities and performances when dealing with large and complex datasets.
Article
Full-text available
A method is presented to recover 3D scene structure and camera motion from multiple images without the need for correspondence information. The problem is framed as finding the maximum likelihood structure and motion given only the 2D measurements, integrating over all possible assignments of 3D features to 2D measurements. This goal is achieved by means of an algorithm which iteratively refines a probability distribution over the set of all correspondence assignments. At each iteration a new structure from motion problem is solved, using as input a set of 'virtual measurements ' derived from this probability distribution. The distribution needed can be efficiently obtained by Markov Chain Monte Carlo sampling. The approach is cast within the framework of Expectation-Maximization, which guarantees convergence to a local maximizer of the likelihood. The algorithm works well in practice, as will be demonstrated using results on several real image sequences. 1 Introduction A primary obj...
Article
Photogrammetric methods for dense 3D surface reconstruction are increasingly available to both professional and amateur users who have requirements that span a wide variety of applications. One of the key concerns in choosing an appropriate method is to understand the achievable accuracy and how choices made within the workflow can alter that outcome. In this paper we consider accuracy in two components: the ability to generate a correctly scaled 3D model; and the ability to automatically deliver a high quality data set that provides good agreement to a reference surface. The determination of scale information is particularly important, since a network of images usually only provides angle measurements and thus leads to unscaled geometry. A solution is the introduction of known distances in object space, such as base lines between camera stations or distances between control points. In order to avoid using known object distances, the method presented in this paper exploits a calibrated stereo camera utilizing the calibrated base line information from the camera pair as an observational based geometric constraint. The method provides distance information throughout the object volume by orbiting the object.
Article
Stratigraphic archaeological excavations demand high-resolution documentation techniques for 3D recording. Today, this is typically accomplished using total stations or terrestrial laser scanners. This paper demonstrates the potential of another technique that is low-cost and easy to execute. It takes advantage of software using Structure from Motion (SfM) algorithms, which are known for their ability to reconstruct camera pose and threedimensional scene geometry (rendered as a sparse point cloud) from a series of overlapping photographs captured by a camera moving around the scene. When complemented by stereo matching algorithms, detailed 3D surface models can be built from such relatively oriented photo collections in a fully automated way. The absolute orientation of the model can be derived by the manual measurement of control points. The approach is extremely flexible and appropriate to deal with a wide variety of imagery, because this computer vision approach can also work with imagery resulting from a randomly moving camera (i.e. uncontrolled conditions) and calibrated optics are not a prerequisite. For a few years, these algorithms are embedded in several free and low-cost software packages. This paper will outline how such a program can be applied to map archaeological excavations in a very fast and uncomplicated way, using imagery shot with a standard compact digital camera (even if the images were not taken for this purpose). Archived data from previous excavations of VIAS-University of Vienna has been chosen and the derived digital surface models and orthophotos have been examined for their usefulness for archaeological applications. The absolute georeferencing of the resulting surface models was performed with the manual identification of fourteen control points. In order to express the positional accuracy of the generated 3D surface models, the NSSDA guidelines were applied. Simultaneously acquired terrestrial laser scanning data -- which had been processed in our standard workflow -- was used to independently check the results. The vertical accuracy of the surface models generated by SfM was found to be within 0.04 m at the 95 % confidence interval, whereas several visual assessments proved a very high horizontal positional accuracy as well.
Article
This paper presents a method for extracting distinctive invariant features from images that can be used to perform reliable matching between different views of an object or scene. The features are invariant to image scale and rotation, and are shown to provide robust matching across a substantial range of affine distortion, change in 3D viewpoint, addition of noise, and change in illumination. The features are highly distinctive, in the sense that a single feature can be correctly matched with high probability against a large database of features from many images. This paper also describes an approach to using these features for object recognition. The recognition proceeds by matching individual features to a database of features from known objects using a fast nearest-neighbor algorithm, followed by a Hough transform to identify clusters belonging to a single object, and finally performing verification through least-squares solution for consistent pose parameters. This approach to recognition can robustly identify objects among clutter and occlusion while achieving near real-time performance.
A comparison of dense matching algorithms for scaled surface reconstruction using stereo camera rigs. ISPRS Journal of Photogrammetry and Remote Sensing 78, 157e167 SURF: speeded up robust features A comparison of camera base calculation methods. The ISU Journal: Stereoscopy
  • A H Ahmadabadian
  • S Robson
  • J Boehma
  • M Shortisb
  • K Wenzelc
  • D Fritschc
Ahmadabadian, A.H., Robson, S., Boehma, J., Shortisb, M., Wenzelc, K., Fritschc, D., 2013. A comparison of dense matching algorithms for scaled surface reconstruction using stereo camera rigs. ISPRS Journal of Photogrammetry and Remote Sensing 78, 157e167. Bay, H., Ess, A., Tuytelaars, T., Van Gool, L., 2008. SURF: speeded up robust features. Computer Vision and Image Understanding 110, 346e359. Bercovitz, J., 2005. A comparison of camera base calculation methods. The ISU Journal: Stereoscopy. http://www.44bx.com/vic3d/bases.html (last accessed 01.07.13.).
Multi-image 3D reconstruction data evaluation Journal of Cultural Her-itage Available online 17
  • A Koutsoudis
  • B Vidmar
  • G Ioannakis
  • F Arnaoutoglou
  • G Pavlidis
  • C Chamzas
Koutsoudis, A., Vidmar, B., Ioannakis, G., Arnaoutoglou, F., Pavlidis, G., Chamzas, C., 2012. Multi-image 3D reconstruction data evaluation. Journal of Cultural Her-itage. http://dx.doi.org/10.1016/j.culher.2012.12.003 (in press). Available online 17 January 2013.
Mobile 3D Mapping with a Low-cost UAV System on Example of a Landfill Survey Allgemeine Vermessungs-nachrichten AVN
  • F Neitzel
  • J Klonowski
  • S Siebert
  • J.-P Deshbach
Neitzel, F., Klonowski, J., Siebert, S., Deshbach, J.-P., 2011. Mobile 3D Mapping with a Low-cost UAV System on Example of a Landfill Survey, vol. 10. Allgemeine Vermessungs-nachrichten AVN, Wichmann VDE-Verlag, Berlin e Offenbach.
Close-range photogrammetry vs. 3D scanning: comparing data capture, processing and model generation in the field and the lab Avenue Campus Low-cost and open-source solutions for automated image orientation e a critical overview
  • R Opitz
  • K Simon
  • A Barnes
  • K Fisher
  • L Lippiello
Opitz, R., Simon, K., Barnes, A., Fisher, K., Lippiello, L., March 26e29, 2012. Close-range photogrammetry vs. 3D scanning: comparing data capture, processing and model generation in the field and the lab. In: Proceedings of the Computer Applications and Quantitative Methods in Archaeology (CAA). Avenue Campus, University of Southampton, England. Remondino, F., Del Pizzo, S., Kersten, P.T., Troisi, S., 2012. Low-cost and open-source solutions for automated image orientation e a critical overview. Lecture Notes in Computer Science 7616, 40e54. Renfrew, C., 1984. Speculations on the use of Early Cycladic sculpture. In: