Now showing 1 - 10 of 13
  • Publication
    Identification and correction of flying pixels in range camera data
    ( 2010)
    Sabov, A.
    ;
    Krüger, J.
    This paper focuses on errors which are possible to occur in the depth measurements of range cameras. Range cameras can capture 3D information of a scene by sending out infrared light and then measuring the reflections. Wrong measurements occur at the edges of objects where the depth level changes. A depth value between the foreground and background level is measured which creates a so-called "flying pixel" when displaying the 3D points. In this paper different methods for the identification of flying pixels are presented and compared. The advantages and drawbacks of each method are discussed. Then a simple method for the correction of flying pixel errors is presented and its limitations are shown. The final method for correction is presented which is based on segmenting the pixel matrix into horizontal and vertical scanlines. After segmentation, linear segments can be identified to which the pixels can be mapped. The paper concludes with the evaluation of the presented methods to show their effectiveness.
  • Publication
    Virtual reconstruction of 3D scenes based on range cameras
    ( 2009)
    Sabov, A.
    ;
    Krüger, J.
    Virtual reconstruction of existing objects and environments is needed in many different areas such as the planning of building extensions, quality assurance for production processes and city reconstructions for geographic information systems. Different scanner systems have been established which meet the demands on the application. For applications such as computer aided facility management a short scanning time is the most important factor instead of high precision. Range cameras are a new generation of 3D scanners which can measure distances to their environment directly with a high frame rate. In this paper a reconstruction method is presented which is specific to range camera data.
  • Publication
    Segmentation of 3D points from range camera data using scanlines
    ( 2008)
    Sabov, A.
    ;
    Krüger, J.
    This paper focuses on the segmentation of 3D points from range camera data. Range cameras can capture 3D information of a scene by sending out infrared light and then measuring the reflections. A segmentation algorithm for the detection of planar surfaces is presented which is robust against erroneous data from the range cameras. It uses a grid of horizontal and vertical scanlines as intermediate primitives for the final planar region segmentation. By using the scanlines, the task of planar segmentation can be separated into two tasks which are less complex: line segmentation and line combination. The usage of higher primitives improves the segmentation time compared to the direct operation on the 3D point data. The algorithm is described in detail and evaluated on a test scene.
  • Publication
    Szenariomanagement für internetbasierte Trainingsdienste
    ( 2008)
    Krüger, J.
    ;
    Schreck, G.
    ;
    Sabov, A.
  • Publication
    Registrierung von 3D-Szenen für das Facility Management
    ( 2008)
    Sabov, A.
    ;
    Krüger, J.
    In diesem Beitrag werden zwei Verfahren zur Rekonstruktion von 3D-Szenen mit Hilfe von Tiefenkameras vorgestellt. Die Verfahren lassen sich im Bereich des Facility Managements für dreidimensionale Vermessungsaufgaben einsetzen. Die Rekonstruktion wird anhand von Aufnahmen eines Büroraums demonstriert.
  • Publication
  • Publication
    Data evaluation for depth calibration of a customary PDM range imaging sensor considering objects with different albedo
    ( 2008)
    Radmer, J.
    ;
    Sabov, A.
    ;
    Krüger, J.
    For various applications, such as object recognition or tracking and especially when the object is partly occluded or articulated, 3D information is crucial for the robustness of the application. A recently developed sensor to aquire distance information is based on the photo mixer device (PMD) technique. This article presents an easy but accurate data acquisition method for data evaluation of a customary sensor. Data evaluation focuses on the detection of the over- and underexposured data under consideration of objects with two different albedos. This improves the exactitude of the data for the study of the systematic errors of this sensor. Therefore the work of this article can be seen as an intermediate result on the way to a PMD range imaging sensor calibration. Entnommen aus TEMA
  • Publication
    Distance data improvement for a customary PMD range imaging sensor
    ( 2008)
    Sabov, A.
    ;
    Radmer, J.
    ;
    Krüger, J.
    Robust 3D information is crucial for various applications, such as object recognition or tracking. A recently developed sensor to acquire distance information is based on the Photo Mixer Device (PMD) technique. The current camera generation still has some drawbacks compared to other 3D sensors. One common error source for any camera is the lens. Imprecise manufacturing and positioning lead to distorted images and incorrect distance measurements. In this paper several calibration techniques are used to identify the intrinsic parameters of the camera. A camera model which considers the real path of the reflected light ray is defined. The resulting distance values still have an offset to the real distance values. A calibration setup is presented that uses two rangefinders to cal ibrate the distance values. The dependency of the offset on different parameters is evaluated and a calibration matrix is created to correct the distance values in operation.
  • Publication
    Erhöhung der Informationsqualität von PMD-basierten 3D-Kameras
    ( 2007)
    Sabov, A.
    ;
    Krüger, J.
    PMD-Kameras können direkte 3D-lnformationen über Ihre Umgebung liefern und eröffnen dadurch neue Anwendungsfelder im 3D-Bereich. In diesem Beitrag werden zwei Verfahren vorgestellt, welche die Informationsqualität der Kameradaten erhöhen. Das erste Verfahren erhöht die Genauigkeit der Distanzmessungen indem es optimale Belichtungszeiten für die Kamera berechnet und mehrere Aufnahmen kombiniert. Das zweite Verfahren verbessert die Graustufenbilder der Kamera indem es die inhomogene Bestrahlung herausrechnet.
  • Publication