Journal: International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences

Abbreviation

Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci.

Publisher

ISPRS

Journal Volumes

ISSN

1682-1750
2194-9034
1682-1777

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2000 - 2009662010 - 201913
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Publications 1 - 10 of 79
  • Image-Based Surface Measurement for Close-Range Heritage Documentation
    Item type: Conference Paper
    Remondino, Fabio; Menna, Fabio (2008)
    International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences
    Recent new developments in the electronics have leaded to the manufacturing of new high-resolution digital sensors (up to 39 mega pixel) for terrestrial cameras. These technological innovations, together with new processing algorithms of image matching, allow to obtain image-based surface models in an almost automatic way with an accuracy and a detail level that can besurely compared with the one achievable with active sensors. With this in mind, we present new developments in terrestrial 3D surface reconstruction and object modeling using digital images, reporting some tests conducted using low cost digital cameras and commercial or in-house software. The tests were conducted selecting different kinds of objects (low relief, statue, buildings, small heritage find, etc.), with different camera configurations and different image resolutions. Different image matching procedures are analyzed, comparing area-based, feature-based or an integration of both. A critical examination of the results is presented, with particular attention to the daily archaeological or heritage documentation purpose.
  • Image-based 3D modeling of the Erechteion, Acropolis of Athens
    Item type: Conference Paper
    Remondino, Fabio; El-Hakim, Sabry; Baltsavias, Emmanuel; et al. (2008)
    International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences
    In this contribution, we report on the image-based modeling (IBM) results of the Erechtheion monument, located inside the Acropolis of Athens, Greece. The work is part of the project “Development of Geographic Information Systems at the Acropolis of Athens“. An aim of the project is the 3D documentation of the whole Acropolis, one of the major archaeological sites world-wideincluded in the UNESCO World Heritage list. The largest part of the monument was digitised with laser scanning, while the main objective of IBM was to model difficult-to- access areas not covered by the scanner but also for comparison with laser scanning for scientific investigations. For the 3D modeling, as the Erechtheion contains some typical architectural elements (like columns, flat walls, etc), some manual measurements were necessary. On the other hand, for some detailed areas automated approaches for densesurface reconstructions are applied. For these parts we compared the image matching results with the surfaces coming from a laser scanner.
  • Hierarchical Clustered Outlier Detection in Laser Scanner Point Clouds
    Item type: Conference Paper
    Sotoodeh, Soheil (2007)
    International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences
    Cleaning laser scanner point clouds from erroneous measurements (outliers) is one of the most time consuming tasks that has to bedone before modeling. There are algorithms for outlier detection in different applications that provide automation to some extent butmost of the algorithms either are not suited to be used in arbitrary 3 dimensional data sets or they deal only with single outliers orsmall scale clusters. Nevertheless dense point clouds measured by laser scanners may contain surface discontinuities, noise and diffrentlocal densities due to the object geometry and the distance of the object to the scanner; Consequently the scale of outliers may varyand they may appear as single or clusters. In this paper we have proposed a clustering algorithm that approaches in two steps with theminimum user interaction and input parameters while it can cop with different scale outliers. In the first step the algorithm deals withlarge outliers (those which are very far away from main clusters) and the second step cops with small scale outliers. Since the algorithmis based on clustering and uses both geometry and topology of the points it can detect outlier clusters in addition to single ones. Wehave evaluated the algorithm on a simulated data and have shown the result on some real terrestrial point clouds. The results explainthe potential of the approach to cop with arbitrary point clouds and different scale erroneous measurements.
  • Processing of UAV based Range Imaging data to generate detailed elevation models of complex natural structures
    Item type: Conference Paper
    Kohoutek, Tobias K.; Eisenbeiss, Henri (2012)
    International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences
    Unmanned Aerial Vehicles (UAVs) are more and more used in civil areas like geomatics. Autonomous navigated platforms have a great flexibility in flying and manoeuvring in complex environments to collect remote sensing data. In contrast to standard technologies such as aerial manned platforms (airplanes and helicopters) UAVs are able to fly closer to the object and in small-scale areas of high-risk situations such as landslides, volcano and earthquake areas and floodplains. Thus, UAVs are sometimes the only practical alternative in areas where access is difficult and where no manned aircraft is available or even no flight permission is given. Furthermore, compared to terrestrial platforms, UAVs are not limited to specific view directions and could overcome occlusions from trees, houses and terrain structures. Equipped with image sensors and/or laser scanners they are able to provide elevation models, rectified images, textured 3D-models and maps. In this paper we will describe a UAV platform, which can carry a range imaging (RIM) camera including power supply and data storage for the detailed mapping and monitoring of complex structures, such as alpine riverbed areas. The UAV platform NEO from Swiss UAV was equipped with the RIM camera CamCube 2.0 by PMD Technologies GmbH to capture the surface structures. Its navigation system includes an autopilot. To validate the UAV-trajectory a 360° prism was installed and tracked by a total station. Within the paper a workflow for the processing of UAV-RIM data is proposed, which is based on the processing of differential GNSS data in combination with the acquired range images. Subsequently, the obtained results for the trajectory are compared and verified with a track of a UAV (Falcon 8, Ascending Technologies) carried out with a total station simultaneously to the GNSS data acquisition. The results showed that the UAV’s position using differential GNSS could be determined in the centimetre to the decimetre level. The RIM data indicated a high noise level in the measured distance image, due to the vibrations caused by the flight system. Multi-image processing reduced the noise level of the distance image. The produced elevation models from a test area show the high potential of the proposed method for complex structures such as riverbeds.
  • DSM Generation from early ALOS/PRISM Data using SAT-PP
    Item type: Other Conference Item
    Wolff, Kirsten; Grün, Armin (2007)
    International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences
    The new Japanese optical sensor ALOS/PRISM which was launched in January 2006 has stereo capabilities which can be used for a great number of applications and products. One of the most important products is the generation of Digital Surface Models (DSMs). With SAT-PP (Satellite Image Precision Processing) our group has developed a suite of new methods and a software package which can be used for the 3D processing of optical Linear Array CCD – based satellite sensor systems. The software was already used successfully for the DSM generation with e.g. IKONOS, QuickBird and SPOT5 high resolution image data. Here we will demonstrate the functionality of the automated image matcher for the generation of DSMs by using early ALOS/PRISM data with a ground sampling distance of 2.5 meters. We have tested our methods of DSM generation using the ALOS/PRISM dataset of two different testfields, which are located in theareas of Bern/Thun (Switzerland) and Okazaki (Japan). They have different topography and land use features (mountainous, city, forest, open and mixed areas). For a detailed quality control of the DSM generation, reference data for three sub areas of the testfield Bern/Thun were available and one sub area in Okazaki. A detailed analysis is presented for certain areas with special and homogeneous topography or land use characteristics. The overall height RMSE for the three sub-areas was 2-3 pixels depending primarily on surface roughness, vegetation and image texture and image quality. The height RMSE values for the specific areas ranged from less than 2 pixels (open areas) to 5 pixels in a tree-covered area. ALOS/PRISM images have particular radiometric problems which do not influence the final results significantly, but they can influence the DSM generation locally. Therefore we give also an analysis of image artifacts.
  • Change Detection in Mire Ecosystems
    Item type: Conference Paper
    Waser, L. T.; Baltsavias, Emmanuel; Eisenbeiss, H.; et al. (2007)
    International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences
    The objective of this paper is to present an approach for assessing tree growth and shrub encroachment between 1997 and 2002 inopen mire land using CIR-aerial images, DSMs and LiDAR data. The study area is located in the Pre-alpine zone of Central Switzerland. The present study was carried out in the framework of the Swiss Mire Protection Program, where changes of forest area are a key issue. Automatic DSMs were generated from CIR- aerial images of 1997 and 2002. This automated DSM generation is based on high accuracy, intelligent matching methods developed at ETHZ which are able to produce very dense and detailed DSMs that allow a good 3D modelling of trees and shrubs, and a multitemporal analysis of their growth pattern. Forest masks from both years of various levels of detail were then generated combining canopy covers derived from the DSMs using multi-resolution segmentation and a fuzzy classification. On the basis of these forest masks fractional tree/shrub covers were generated using explanatory variables derived from the DSMs and logistic regression models. The models reveal a general decrease of forest area between 1997 and 2002. On the other side, the models also indicate real shrub encroachment and tree growth in open mire land.
  • Semi-automatic orientation of images with respect to a point cloud system
    Item type: Conference Paper
    Novák, David (2008)
    International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences
    This paper presents the results of a master thesis in which it was tried to orient a set of images of an object to a point cloud of the same object. As test object the “Semper Sternwarte” in Zürich was used. As data sets a dense point cloud from a laser scanner and a sparse point cloud obtained by photogrammetric means, as well as the orientation of the images were used. Precisely orientated images with respect to a point cloud can be used to incorporate an edge-constrained triangulation techniques, blunder and outlier detection, which leads to an overall better representation of a 3D model. This paper looks at a specific semi-automated work flow using self-programmed tools and tries to determine whether the work flow is suitable for this task or not.
  • Calibration for increased accuracy of the range imaging camera SwissRanger
    Item type: Conference Paper
    Kahlmann, Timo; Remondino, Fabio; Ingensand, Hilmar (2006)
    International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences ~ Proceedings of the ISPRS Commission V Symposium 'Image Engineering and Vision Metrology'
    Range imaging is a new suitable choice for measurement and modeling in many different applications. But due to the technology’srelatively new appearance on the market with a few different realizations, the knowledge of its capabilities is very low. In most applications, like robotics and measurement systems, the accuracy wanted, lies at some millimeters. The raw data of range imaging cameras do not reach this level. Therefore, the calibration of the sensors output is needed. In this paper some of the parameters which influence the behavior and performance of the range imaging camera SwissRangerTM (provided by the Swiss Center for Electronics and Microtechnology - CSEM) are described. Because of the highly systematic structure and correlations between parameters and output data, a parameter based calibration approach is presented. This includes a photogrammetric camera calibration and a distance system calibration with respect to the reflectivity and the distance itself.
  • 3-dimensional pre- and post-fire comparison of forest areas
    Item type: Conference Paper
    Akca, Devrim; Stylianidis, Efstratios; Poli, Daniela; et al. (2018)
    International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences
  • Real-Time Video-Based Reconstruction of Urban Environments
    Item type: Conference Paper
    Mordohai, P.; Frahm, Jan-Michael; Akbarzadeh, A.; et al. (2007)
    International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences
    We present an approach for automatic 3D reconstruction of outdoor scenes using computer vision techniques. Our system collectsvideo, GPS and INS data which are processed in real-time to produce geo-registered, detailed 3D models that represent the geometryand appearance of the world. These models are generated without manual measurements or markers in the scene and can be used forvisualization from arbitrary viewpoints, documentation and archiving of large areas. Our system consists of a data acquisition systemand a processing system that generated 3D models from the video sequences off-line but in real-time. The GPS/INS measurementsallow us to geo-register the pose of the camera at the time each frame was captured. The following stages of the processing pipelineperform dense reconstruction and generate the 3D models, which are in the form of a triangular mesh and a set of images that providetexture. By leveraging the processing power of the GPU, we are able to achieve faster than real-time performance, while maintainingan accuracy of a few cm.
Publications 1 - 10 of 79