Showing papers by "Viktor Kaufmann published in 2008"

Application of Terrestrial Photogrammetry for Glacier Monitoring in Alpine Environments

Abstract: The present paper investigates the application of terrestrial photogrammetry for glacier mapping using either consumer, semiprofessional or professional SLR digital cameras and a fully digital photogrammetric workflow. * Corresponding author.

Documentation of the retreat of Gössnitzkees and Hornkees Glaciers (Hohe Tauern Range, Austrian Alps) for the Time Period 1997-2006 by Means of Aerial Photogrammetry

Abstract: Gössnitzkees and Hornkees are two small cirque glaciers (2006: 58.9 and 30.6 ha, respectively) located in the Schober group of the Hohe Tauern range of the Eastern Alps in Austria. Th e glacier history of both glaciers has already been documented for the time period 1850-1997 based on fi eld evidence, historical maps and aerial photographs. Th e temporal change in area, surface height, and volume of both glaciers was presented numerically and graphically. In this paper we intend to extend the observation period to the present. Aerial photographs of 2002 and 2006 covering the area of interest were made available by the Tyrolean regional government and the Austrian Federal Offi ce of Metrology and Surveying, Vienna. A digital photogrammetric workfl ow was applied to the image data provided. Based on these multi-temporal data we computed the volumetric and areal change of both glaciers along with the respective numerical values at elevational intervals of 50 m. Th e change in surface height and area of both glaciers is shown in thematic maps. Th e results include a new orthophoto map at 1:10,000 scale representing the glacial stage of 2006 and an estimation of the equilibrium line altitude.

Geometric Calibration of the Hasselblad H3D Medium Format Camera

Abstract: The Hasselblad H3D digital camera, which is designed for professional studio shootings, is equipped with a 39 megapixel digital back. It would be desirable to use this very high geometric resolution in photogrammetric applications. Unfortunately, the digital back does not have a tight connection to the camera body. In addition, the unknown internal image processing algorithms and the autofocus lens make it difficult to obtain a reliable camera calibration. In this paper, we investigate whether the Hasselblad H3D camera can be calibrated for use in photogrammetric applications. Repeated calibrations were performed using a 2D (planar) target as well as a 3D test field. Results of the individual calibration projects are compared in order to analyze the stability of the camera over time. We also investigate if there is a fixed pattern of systematic image residuals (after removal of radial distortion), which could be described by a distortion grid. Software tools were developed for semi-automatic calibration using the MATLAB programming environment. This calibration software consists of a graphical user interface supporting automated and precise measurement of circular point targets, robust calculation of initial orientation parameters and bundle adjustment with self-calibration capabilities. The commercial software package PhotoModeler (Eos Systems Inc./Vancouver) was also used for comparison to derive calibration parameters based on the planar target. * Corresponding author.