J.-A. Beraldin’s research while affiliated with National Research Council Canada and other places

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Publications (144)


Testing proposal for an optically-tracked CMM (OTCMM) in a pre-normative context
  • Conference Paper

July 2016

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61 Reads

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1 Citation

J.-A. Beraldin

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Recent interest in portable coordinate measuring systems (CMS) has attracted the attention of industrial users and the technical community at large. Articulated-arm CMM and Optically-Tracked CMM (OTCMM) systems have emerged from being nice-to-have to must-have 3D equipment on the shop floor. Portability and flexibility for in-process product measurements and verification are displacing more traditional methods that require fixed gantries, especially when OTCMM are combined with tracking devices that can compensate for the vibration levels of a typical shop floor. The current set of recognized contact CMS standards produced by ISO, VDI, ASME organisations cover fixed-gantry CMM. However, these standards cover one class of OTCMM i.e. laser trackers and neglect the class of OTCMM that include spherical-stylus touch probe tracked by contrast targets-based optical triangulation methods. It is within this context that we propose a harmonisation scheme for terminology, discuss test methods complemented with experimental data, and reference artefacts for the purpose of ensuring comparability of CMS and helping in pre-normative documentary/physical standards definition.


Results of self-calibrating bundle adjustment for the tested photogrammetric systems. Interior orientation and additional parameters are reported along with internal assessment in image and object space.
Difference between target coordinates measured with the reference system D750-50mm and D750-45mm.
EXPERIMENTS ON CALIBRATING TILT-SHIFT LENSES FOR CLOSE-RANGE PHOTOGRAMMETRY
  • Article
  • Full-text available

June 2016

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971 Reads

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16 Citations

The International Archives of the Photogrammetry Remote Sensing and Spatial Information Sciences

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One of the strongest limiting factors in close range photogrammetry (CRP) is the depth of field (DOF), especially at very small object distance. When using standard digital cameras and lens, for a specific camera – lens combination, the only way to control the extent of the zone of sharp focus in object space is to reduce the aperture of the lens. However, this strategy is often not sufficient; moreover, in many cases it is not fully advisable. In fact, when the aperture is closed down, images lose sharpness because of diffraction. Furthermore, the exposure time must be lowered (susceptibility to vibrations) and the ISO increased (electronic noise may increase). In order to adapt the shape of the DOF to the subject of interest, the Scheimpflug rule is to be applied, requiring that the optical axis must be no longer perpendicular to the image plane. Nowadays, specific lenses exist that allow inclining the optical axis to modify the DOF: they are called tilt-shift lenses. In this paper, an investigation on the applicability of the classic photogrammetric model (pinhole camera coupled with Brown’s distortion model) to these lenses is presented. Tests were carried out in an environmentally controlled metrology laboratory at the National Research Council (NRC) Canada and the results are hereafter described in detail.

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Results of self-calibrating bundle adjustment for the tested photogrammetric systems. Interior orientation and additional parameters are reported along with internal assessment in image and object space.
Difference between target coordinates measured with the reference system D750-50mm and D750-45mm.
EXPERIMENTS ON CALIBRATING TILT-SHIFT LENSES FOR CLOSE-RANGE PHOTOGRAMMETRY

June 2016

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603 Reads

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15 Citations

The International Archives of the Photogrammetry Remote Sensing and Spatial Information Sciences

One of the strongest limiting factors in close range photogrammetry (CRP) is the depth of field (DOF), especially at very small object distance. When using standard digital cameras and lens, for a specific camera – lens combination, the only way to control the extent of the zone of sharp focus in object space is to reduce the aperture of the lens. However, this strategy is often not sufficient; moreover, in many cases it is not fully advisable. In fact, when the aperture is closed down, images lose sharpness because of diffraction. Furthermore, the exposure time must be lowered (susceptibility to vibrations) and the ISO increased (electronic noise may increase). In order to adapt the shape of the DOF to the subject of interest, the Scheimpflug rule is to be applied, requiring that the optical axis must be no longer perpendicular to the image plane. Nowadays, specific lenses exist that allow inclining the optical axis to modify the DOF: they are called tilt-shift lenses. In this paper, an investigation on the applicability of the classic photogrammetric model (pinhole camera coupled with Brown’s distortion model) to these lenses is presented. Tests were carried out in an environmentally controlled metrology laboratory at the National Research Council (NRC) Canada and the results are hereafter described in detail.


Figure 1. Test-object and dimensions (Cathédrale de la Major) 
Figure 2. Procedural workflow (Cathédrale de la Major) 
Figure 3. Test-object and dimensions (ISO1 Laboratory) 
Figure 4. Procedural workflow (ISO 1 Laboratory) 
Figure 6. The point cloud extracted with the 5°-dataset. 50 mm-lens α # Images σ (mm) Histogram 5° 15 0.88 10° 15 0.67 5°+10° 27 0.67
On the evaluation of photogrammetric methods for dense 3D surface reconstruction in a metrological context

May 2014

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483 Reads

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36 Citations

ISPRS Annals of the Photogrammetry Remote Sensing and Spatial Information Sciences

This paper discusses a methodology to evaluate the accuracy of recently developed image-based 3D modelling techniques. So far, the emergence of these novel methods has not been supported by the definition of an internationally recognized standard which is fundamental for user confidence and market growth. In order to provide an element of reflection and solution to the different communities involved in 3D imaging, a promising approach is presented in this paper for the assessment of both metric quality and limitations of an open-source suite of tools (Apero/MicMac), developed for the extraction of dense 3D point clouds from a set of unordered 2D images. The proposed procedural workflow is performed within a metrological context, through inter-comparisons with "reference" data acquired with two hemispherical laser scanners, one total station, and one laser tracker. The methodology is applied to two case studies, designed in order to analyse the software performances in dealing with both outdoor and environmentally controlled conditions, i.e. the main entrance of Cathédrale de la Major (Marseille, France) and a custom-made scene located at National Research Council of Canada 3D imaging Metrology Laboratory (Ottawa). Comparative data and accuracy evidence produced for both tests allow the study of some key factors affecting 3D model accuracy.


Short-range 3-D Imaging Systems Characterization using Known Artifacts

January 2012

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10 Reads

A set of test procedures and known artifacts to characterize the capability of short-range triangulation-based 3-D imaging systems are presented. The approach consists of scanning metallic and coated glass artifacts characterized by measurements with known uncertainties which are much less than the measurement uncertainties produced by the System Under Test (SUT). The artifacts were grouped on the same plate for portability purpose. To define a set of test procedures that is practical, simple to perform and easy to understand, we decided to use a terminology that is already well-known in the manufacturing field, i.e., Geometric dimensioning and tolerancing (GD&T). In its current version, the NRC Portable Characterization Target (NRC-PCT) is specifically designed for the characterization of systems with depths of field from 50 mm to 500 mm. A number of tests were performed to validate the capability of the NRCPCT. These results, along with some basic information on 3-D imaging systems, will be presented in the paper.


Three Dimensional Laser Scanning Technology

February 2010

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228 Reads

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13 Citations

Written by a team of international experts, this book provides a comprehensive overview of the major applications of airborne and terrestrial laser scanning. It focuses on principles and methods and presents an integrated treatment of airborne and terrestrial laser scanning technology. After consideration of the technology and processing methods, the book turns to applications, such as engineering, forestry, cultural heritage, extraction of 3D building models, and mobile mapping. This book brings together the various facets of the subject in a coherent text that will be relevant for advanced students, academics and practitioners.




Photogrammetry (mm) 3D model (mm) ∆ (mm)
Photogrammetry and 3D Scanning: Assessment of Metric Accuracy for the Digital Model of Danatello's Maddalena

April 2009

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910 Reads

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15 Citations

The deployment of 3D optical scanning technologies for measuring three-dimensional shapes of sculptures of high morphological complexity, have seen recently a development so noticeable that it emerges as one of the most promising methods for the analysis and preservation of the Cultural Heritage. In spite of an undoubted richness of information produced with this technique, the method for generating a digital model from single 3D acquisitions involves errors propagation that may deteriorate the actual metric accuracy attainable with such procedure. The activity reported in this paper describes a recent experiment in 3D scanning of a highly complex sculpture: the wooden statue "Maddalena" by Donatello, kept in the museum of the "Opera del Duomo", in Florence. The acquisitions, taken with a commercial system based on fringe projection, give a local measurement uncertainty of about 70m, but when the complete model is generated by automatic alignment of the raw 3D images in a common coordinate system, possible scale variations might be involved, especially along the height of the statue. With this preliminary work, the authors want to verify the metric reliability of the three-dimensional model, obtained through iterative alignments of single 3D acquisitions. For this purpose, a measurement over well-identified features of the sculpture have been performed and the distances between couples of significant points have been calculated with photogrammetric operations. By repeating the same measurements on the 3D model, a corresponding set of point-to-point distances have been evaluated and compared with the photogrammetric results.


Extracting information from very large datasets: Modelling the erechtheion

January 2009

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65 Reads

The National Research Council in Canada (NRCC) has created a framework for gleaning information from very large TLS and imagery datasets, an evolution demonstrated in the Erechtheion project. Cultural heritage has been a central factor in the NRCC research and development program in 3D technologies. Erechtheion is on the Acropolis, next to the Parthenon in Athens, Greece, whos refurbishment began in 1987. The 'Porch of the Maidens' is on the north side and consists of six draped female figures. NRCC has created algorithms for 3D-image processing, management and real-time visualization as part of Atelier3D.ca, a general framework evolved for acquisition, processing, modeling, analysis and visualization of very large 2D/3D datasets created from 3D point-clouds and imagery. Atelier 3D.ca allows view-dependent, real-time visualization of multi-resolution models. Algorithms have been created for displaying these datasets interactively at full resolution on inexpensive laptops or desktop computers.


Citations (78)


... Two notable examples of the successful 3D digitalization are results of the National Research Council of Canada (NRCC) and IBM. The NRCC efforts are interesting because they focus on building robust, field-deployable systems, and consequently their papers echo some of the same concerns raised in this paper [3]. The IBM efforts are interesting first because they scanned a statue under field conditions, and second because they used a structured-light scanner in conjunction with photometric stereo, producing geometry at 2.0 mm and a normal vector field at sub-millimeter resolution [4]. ...

Reference:

Geometric Investigation of Large 3D Spatial Data for Virtual Museum Applications
Digital 3D imaging system for rapid response on remote sites
  • Citing Article
  • January 1999

... The first step is the calculation of defocusing error. The defocusing error is defined through the aperture that is presented as a relationship [2,23]: ...

EXPERIMENTS ON CALIBRATING TILT-SHIFT LENSES FOR CLOSE-RANGE PHOTOGRAMMETRY

The International Archives of the Photogrammetry Remote Sensing and Spatial Information Sciences

... However, traditional line laser vision sensors are constrained by the camera's depth of field, allowing them to capture only a limited range of clear images, thus restricting their application in scenarios like thick plate welding. A common approach to enhance the camera's depth of field is to reduce the aperture or shorten the focal length, but this significantly diminishes the resolution of the vision sensor [6]. An alternative approach is to construct a constant-focus optical path within the sensor according to the Scheimpflug principle [7,8]. ...

EXPERIMENTS ON CALIBRATING TILT-SHIFT LENSES FOR CLOSE-RANGE PHOTOGRAMMETRY

The International Archives of the Photogrammetry Remote Sensing and Spatial Information Sciences

... This is conducted by researchers in the field of ICT to stimulate other stakeholders in society to establish the multimedia database [7] as accentuation to the importance of everyone's role. In this regard, the work involved are processing the real time visualization [16], supporting to interactive process and learning [17], getting the ICT (as infrastructure) to increase the presentation (in the form of results) by using laser scan [18] and photogrammetry [19], and the involvement of mobile technology (as a support facility) [20] specially to increase the user engagement for collecting the cultural heritage (as the content of system) digitally [21]. Secondly, the relationships that relate to exploration of resource of digital cultural heritage [3] or multimedia content [6]. ...

Photorealistic 3D Modelling Applied to Cultural Heritage
  • Citing Chapter
  • January 2007

Cognitive Technologies

... Multispectral imaging and 3D surveying techniques can be used for different purposes to provide reliable data to restorers for planning the restoration process or adjust the environmental conditions. In recent years the study and characterisation of artworks' surface by means of different non-invasive digital techniques is quickly evolving (Fontana et al., 2005;Blais et al., 2007;Lahanier et al., 2008;Remondino et al., 2011;Granero-Montagud et al., 2013). Typical outputs are usually represented by pigment identification, colour measurements, extraction of geometric features (brush strokes details), shape' measurements, etc. Range-based 3D modelling techniques (Guidi et al., 2004;Akca, 2007;Blais et al., 2008;Breuckmann, 2011), such as laser scanners and structured light sensors, and image-based 3D modelling technique, such as photogrammetry (Robson et al., 2004;D'Amelio & Lo Brutto, 2009;Barazzetti el al., 2010) can provide for precise and reliable 3D geometrical and radiometric information useful for detailed analyses and inspections. ...

Ultra high-resolution 3D laser color imaging of paintings
  • Citing Chapter
  • August 2008

... Thus, a good digital reconstruction requires a detailed 3D model with a representative set of geometric elements. Hence, the two main requirements for the 3D GIS model are the ability to support the acquisition and handling of a large amount of complex and non-planar 3D geometry and the ability for visualization of these objects which consist of a significant number of geometry elements (El-Hakim and Beraldin 2002). ...

3D modelling of heritage monuments: Increasing realism by combining techniques
  • Citing Article
  • April 2003

GIM International

... Prominent projects such as the Michelangelo Project (1988) and the Pietà Rondanini project (1998) allowed for the rigorous and precise documentation of Michelangelo's works in Italy [12,13]. In 2003, a joint project between the French Center of Museum Research and Restoration and the National Research Council of Canada scanned the pictorial surface and the reverse side of Leonardo da Vinci's Mona Lisa [14]. ...

Immagini digitali tridimensionali di beni artistici
  • Citing Article
  • March 2001

... Other studies used photogrammetric localisation in industry, but this was limited in using one stationary camera to localise moving objects (El-Hakim et. al, 1997;Blais et al., 2001;Böhm et al., 2001). Hofmann-Wellenhof et al. (2002) describes briefly the use of photogrammetry as a navigation method, but no further discussion was made. ...

Comparison of pose estimation methods of a 3D laser tracking system using triangulation and photogrammetry techniques
  • Citing Conference Paper
  • December 2000

Proceedings of SPIE - The International Society for Optical Engineering

... Some active triangulation techniques have emerged from the labs into commercial products. One of such products is the ranging camera line from Servo-Robot (Jupiter and Saturn models) These ranging cameras are based on synchronized triangulations which overcome the large baseline requirement without penalty on resolution and field of vi£!w [23], [24]. In this design, projection and detection are synchronized by means of a pyramidal rotating mirror (Figure 8). ...

Registered intensity and range imaging at 10 mega-samples per second
  • Citing Article
  • January 1992

Optical Engineering