Armin Grün

Stereo cloud‐top height retrieval with ASTER and MISR

The combined multi‐view photogrammetric retrieval of cloud‐top height (CTH) from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and the Multi‐angle Imaging SpectroRadiometer (MISR) is discussed. Although ASTER was designed mainly for land applications, the synergistic use of MISR and ASTER is shown to be valuable for 3D cloud analysis. A new cloud‐adapted matching algorithm based on least‐squares matching (LSM) was used for the photogrammetric processing of both MISR and ASTER. The methods were applied to an ASTER scene over Zürich‐Kloten, Switzerland, in April 2002, which was acquired on‐demand. This case study, with coincident ASTER, MISR and Meteosat‐6 10‐minute Rapid Scans, is treated in detail. As a matching validation option it is shown that, by chance, the cloud motion error for the MISR An‐Aa and ASTER stereo CTHs is approximately the same, independent of the actual cloud height and cloud motion. It was therefore possible to evaluate the accuracy of the MISR An‐Aa matching versus the ASTER matching, independent of artefacts due to the subsequent wind correction. The results were also compared to the operational MISR L2TC stereo CTH results. The results obtained by each of these methods yield consistent values for CTH (uncorrected for wind motion).

Calibration and accuracy testiing of mobile phone cameras

This paper examines the potential of mobile phones to be used as a front-end sensor for photogrammetric procedures and applications. For this purpose we are currently calibrating various mobile phones over our indoor 3D testfield, using self-calibration. Using the same testfield we are performing accuracy tests in order to evaluate the metric performance. This paper reports about first experiences in calibration and accuracy validation of mobile phone cameras.