Peter Dorninger’s research while affiliated with Naturhistorisches Museum Wien and other places

In light of ageing infrastructure, structural condition assessment is a key prerequisite for the provision of reliable, safe and performant infrastructure networks. However, full systematic condition inspections across large transport networks are extremely resource intensive. Thus, network-wide continuous structural monitoring is hardly feasible using classical engineering assessment methods. Modern remote sensing techniques open up new possibilities for infrastructure assessment and monitoring. Three different methods for rapid, contactless and non-invasive infrastructure deformation monitoring are evaluated: (1) satellite radar interferometry (InSAR), (2) airborne laser scanning (ALS) using unmanned aerial vehicles (UAV) and (3) vehicle-mounted mobile laser scanning (MLS). All methods are tested at an integral concrete bridge in Vienna, Austria, and results are contrasted to reference measurements available from several water-level gauges. In addition, thermal deformation is modelled based on the prevailing environmental conditions. Results show that all methods are well capable of detecting general deformation trends, albeit exhibiting different stages of maturity. While the main application of InSAR lies in long-term continuous deformation measurement of the overall structure, MLS and ALS have the benefit of providing a wealth of data through measurement campaigns. All three contactless measurement methods are suitable for supplementing current structural condition assessments.

Unthinkable just a few years ago, the precise laser‐scanning survey of a kilometer‐long tunnel in one day by one operator has become possible. This article describes how 261 scans were taken with a RIEGL VZ‐400i laser scanner to digitize the Zentrum am Berg (ZaB) research tunnel with millimeter resolution. The data has been automatically registered during the acquisition process within the instrument. After applying multistation adjustment, a block adjustment postprocess step, the high accuracy of the point cloud with respect to a network of 35 retroreflective bireflex targets has been approved. For further applications such as analysis, simulation, or visualization, a homogeneous 3D‐meshed surface model has been created automatically from the point cloud representing an as‐built 3D documentation of the tunnel. Digitalisierung des „Zentrum am Berg” Forschungstunnels – Vom Laserscan zum Triangulations‐Modell in einem Tag Vor wenigen Jahren noch undenkbar, ist die präzise Laserscanning‐Vermessung eines kilometerlangen Tunnels an einem Tag durch einen Operator möglich geworden. In diesem Beitrag wird beschrieben, wie 261 Scans mit einem RIEGL VZ‐400i Laserscanner gemacht wurden, um den „Zentrum am Berg” (ZaB) Forschungstunnel mit Millimeterauflösung zu digitalisieren. Die Daten wurden während des Erfassungsprozesses automatisch im Gerät registriert. Nach Anwendung des Multi Station Adjustment, einem Postprozessschritt zur Blockausgleichung aller Scanpositionen, wurde die hohe Genauigkeit der Punktwolke in Bezug auf ein Netz von 35 retroreflektierenden „Bi‐Reflex‐Zielen” bestätigt. Für weitere Anwendungen wie Analyse, Simulation oder Visualisierung wurde aus der Punktwolke automatisch ein homogenes 3D‐Netz‐Oberflächenmodell erstellt, welches einen 3D‐Bestandsplan des Tunnels darstellt.

The protected fossil oyster reef in Stetten, Austria is the world's largest excavated fossil oyster reef, formed by large sea shells. About 50.000 up to 60-cm-long shells cover a 459 m2 large area. The reef consists primarily of Crassostrea gryphoides shells. In this study, our motivation is to reconstruct the original shell positions with automatic 3D object matching and by finding similar or identical objects in a database with determined shell size (Figure 1). Four initial criteria were defined for the object matching: i) iterative neighborhood search near the examined shell, ii) specified shell convexity: down, up, iii) specified shell side: left, right and iv) shell length with 20% tolerance. For all shells matching the criteria, their centrelines were analyzed in the next step. In analysis, the centreline and its neighboring points are profiled. The profiling produces spatial features, such as sphericity, planarity, scattering and change of curvature. The features describe if the lateral surface of a shell is flat, concave, or convex. All analyzed shells are compared to see if they match together by studying left-sided shells with the right ones. The analysis assumes that shell features should be invariant within a potential pair. Finally, the potential matching candidates are brought close together and pairing is completed using an iterative closest point (ICP) algorithm with a constraint that the matching surface cannot intersect between left and right valve. The proposed method gives a possibility to match and link spatially separated complex objects together if their surface properties have enough feature correspondences along their centreline profiles. The matching over distance supports in making spatial interpretations and objects visualizations in several disciplines, including geology, palaeontology, and biology.

The world's largest fossil oyster reef, formed by the giant oyster Crassostrea gryphoides and located in Stetten (north of Vienna, Austria), is studied in this article. Digital documentation of the unique geological site is provided by terrestrial laser scanning (TLS) at the millimeter scale. Obtaining meaningful results is not merely a matter of data acquisition with a suitable device; it requires proper planning, data management, and postprocessing. Terrestrial laser scanning technology has a high potential for providing precise 3D mapping that serves as the basis for automatic object detection in different scenarios; however, it faces challenges in the presence of large amounts of data and the irregular geometry of an oyster reef. We provide a detailed description of the techniques and strategy used for data collection and processing. The use of laser scanning provided the ability to measure surface points of 46,840 (estimated) shells. They are up to 60-cm-long oyster specimens, and their surfaces are modeled with a high accuracy of 1 mm. In addition, we propose an automatic analysis method for identifying and enumerating convex parts of shells. Object surfaces were detected with a completeness of 69% and a correctness of over 75% by means of a fully automated workflow. Accuracy of 98% was achieved in detecting the number of objects. In addition to laser scanning measurements, more than 300 photographs were captured, and an orthophoto mosaic was generated with a ground sampling distance (GSD) of 0.5 mm. This high-resolution 3D information and the photographic texture serve as the basis for ongoing and future geological and paleontological analyses. Moreover, they provide unprecedented documentation for conservation issues at a unique natural heritage site.

We present the first GIS database as an interface of a digital oyster reef and managing tool for a protected natural heritage site. The state of the art in 3D digitizing, data processing, and visualization technologies allows mapping of the world’s largest fossil oyster reef in order to support paleontological investigations of the about 16.5 million years old site. This study is making an evaluation of a large area economically feasible in both time and costs. The reef layer was determined using 3D point measurement method (terrestrial laser scanning). It derived high resolution data of about 150 points per square centimeter with measurement speed up to 1 million points per second. Those points are used to create 1mm digital surface model (DSM) of entire oyster reef. The texture is assigned to the DSM for more realistic visualization resulting in high spatial resolution (0.5mm/px) orthophoto. The aim is to replace the manual survey made in situ and enable the palaeontologist to benefit using those kind of representations. Interpretations of the digital data are based on a data base containing spatial and non-spatial aspects such as shell size, orientation, position, species, state of fragmentation, etc. DSM and orthophoto visualizations are significantly supported by GIS tools providing various possibilities to design required thematic maps and link each individual shell with their descriptive attributes. Keywords: terrestrial laser scanning (TLS); 1mm digital surface model; 0.5mm orthophoto; mapping fossils; GIS database; oyster reef.

The purpose of this study is to illustrate the potential of 3D laser scanning technology in the context of paleontology. This is demonstrated by addressing a particular research question, the extraction of fossilized oyster shell central lines, in a dataset collected from the world's largest fossilized oyster reef whose age is 16.500.000 years. Laser scanning techniques provide a precise and objective methodology to digitally document and study paleontological objects in situ in a non-destructive manner. Analysis of high resolution laser scanning data (1 mm) offers a distinction between geometrical features and therefore supports the interpretation of surrounding topography. The visualization and detection of shell surfaces within the complex surroundings of the oyster reef provide a new room to test and study possibilities of using geometrical features in analysis. The reef's high resolution digital surface model helps to develop new algorithms for object extraction and analysis, such as reliable computations of shell size, orientation and volume. 3D laser scanning is an ideal candidate for multidisciplinary studies. Its results can be combined with those of other disciplines such as photogrammetry, geographic information systems (GIS) or biology and paleontology. http://vss.tuwien.ac.at/fileadmin/t/vss/manuscript_VSS2016.pdf

The world's largest fossilized oyster reef is located in Stetten, Lower Austria excavated during field campaigns of the Natural History Museum Vienna between 2005 and 2008. It is studied in paleontology to learn about change in climate from past events. In order to support this study, a laser scanning and photogrammetric campaign was organized in 2014 for 3D documentation of the large and complex site. The 3D point clouds and high resolution images from this field campaign are visualized by photogrammetric methods in form of digital surface models (DSM, 1 mm resolution) and orthophoto (0.5 mm resolution) to help paleontological interpretation of data. Due to size of the reef, automated analysis techniques are needed to interpret all digital data obtained from the field. One of the key components in successful automation is detection of oyster shell edges. We have tested Reflectance Transformation Imaging (RTI) to visualize the reef data sets for end-users through a cultural heritage viewing interface (RTIViewer). The implementation includes a Lambert shading method to visualize DSMs derived from terrestrial laser scanning using scientific software OPALS. In contrast to shaded RTI no devices consisting of a hardware system with LED lights, or a body to rotate the light source around the object are needed. The gray value for a given shaded pixel is related to the angle between light source and the normal at that position. Brighter values correspond to the slope surfaces facing the light source. Increasing of zenith angle results in internal shading all over the reef surface. In total, oyster reef surface contains 81 DSMs with 3 m x 2 m each. Their surface was illuminated by moving the virtual sun every 30 degrees (12 azimuth angles from 20-350) and every 20 degrees (4 zenith angles from 20-80). This technique provides paleontologists an interactive approach to virtually inspect the oyster reef, and to interpret the shell surface by changing the light source direction. One source of light for shading does show all morphologic features needed for description. Additionally, more details such as fault lines, overlaps and characteristic edges of complex shell structures are clearly detected by simply changing the illumination on the shaded digital surface model. In a further study, the potential of edge detection of the individual shells will be analyzed based on statistical analysis by keeping track of the local accumulative shading gradient. The results are compared to manually identified edges. In a following study phase, the detected edges will be improved by graph cut segmentation. We assume that this technique can lead to automatically extracted teaching set for object segmentation on a complex environment. The project is supported by the Austrian Science Fund (FWF P 25883-N29).

The hypogene cave Märchenhöhle was mapped in 3-D by means of the laser scanning technique. The resulting triangulated model allowed detailed analysis of cave macro-, meso-, and micromorphology to be performed. Parts of the cave that would not be amenable to direct observations while in the cave (e.g., upper parts of large cave chambers and ceilings) could be studied at high resolution. The 3-D cave model-based morphogenetic analysis allowed identification of morphological features of hypogene speleogenesis at various scales and strengthened the attribution of the cave to a hypogene class.

We're premiering the newest scientific video from ORF NEWTON https://www.dropbox.com/s/m5vq16sji75fadq/Newton-Newton_%20Die%20Perlentaucher%20von%20Stetten-1213057219.mp4?dl=0 about the World’s largest fossil oyster reef -- where we are talking about scientific background including ‪geology‬, ‪‎paleontology‬ and ‪‎climatology‬ using ‪photogrammetry‬ and 3D laser scanning. The synergy of those scientific disciplines brings us to reconstruction of event from the Early Miocene epoch caused by high-energy process of short duration, such as strong storm or tsunami. Get to know how many sea shells were found in Austria and impact of high resolution 3D laser scanning data on paleontological investigations!?!

The world's largest fossil oyster reef, formed by the giant oyster Crassostrea gryphoides and located in Stetten (north of Vienna, Austria) is studied in this article. Digital documentation of the unique geological site is provided by terrestrial laser scanning (TLS) at the millimeter scale. Obtaining meaningful results is not merely a matter of data acquisition with a suitable device; it requires proper planning, data management, and postprocessing. Terrestrial laser scanning technology has a high potential for providing precise 3D mapping that serves as the basis for automatic object detection in different scenarios; however, it faces challenges in the presence of large amounts of data and the irregular geometry of an oyster reef. We provide a detailed description of the techniques and strategy used for data collection and processing. The use of laser scanning provided the ability to measure surface points of 46,840 (estimated) shells. They are up to 60-cm-long oyster specimens, and their surfaces are modeled with a high accuracy of 1 mm. In addition, we propose an automatic analysis method for identifying and enumerating convex parts of shells. Object surfaces were detected with a completeness of 69% and a correctness of over 75% by means of a fully automated workflow. Accuracy of 98% was achieved in detecting the number of objects. In addition to laser scanning measurements, more than 300 photographs were captured, and an orthophoto mosaic was generated with a ground sampling distance (GSD) of 0.5 mm. This high-resolution 3D information and the photographic texture serve as the basis for ongoing and future geological and paleontological analyses. Moreover, they provide unprecedented documentation for conservation issues at a unique natural heritage site.