Fast correlation technique for glacier flow monitoring by digital camera and space-borne SAR images
1 Université de Savoie-Polytech Annecy-Chambéry-LISTIC, BP 80439, 74944 Annecy-le-Vieux cedex, France
2 Institut TELECOM, TELECOM ParisTech, CNRS LTCI, 75013 Paris, France
3 Département LPMO, Institut FEMTO-ST, 25044 Besançon, France
4 ISTerre, IRD R219, Université de Savoie, Campus Scientifique, 73376 Le Bourget du Lac Cedex, France
5 EDYTEM, CNRS, Université de Savoie, 73376 Le Bourget du Lac, France
EURASIP Journal on Image and Video Processing 2011, 2011:11 doi:10.1186/1687-5281-2011-11Published: 28 September 2011
Most of the image processing techniques have been first proposed and developed on small size images and progressively applied to larger and larger data sets resulting from new sensors and application requirements. In geosciences, digital cameras and remote sensing images can be used to monitor glaciers and to measure their surface velocity by different techniques. However, the image size and the number of acquisitions to be processed to analyze time series become a critical issue to derive displacement fields by the conventional correlation technique. In this paper, a mathematical optimization of the classical normalized cross-correlation and its implementation are described to overcome the computation time and window size limitations. The proposed implementation is performed with a specific memory management to avoid most of the temporary result re-computations. The performances of the software resulting from this optimization are assessed by computing the correlation between optical images of a serac fall, and between Synthetic Aperture Radar (SAR) images of Alpine glaciers. The optical images are acquired by a digital camera installed near the Argentière glacier (Chamonix, France) and the SAR images are acquired by the high resolution TerraSAR-X satellite over the Mont-Blanc area. The results illustrate the potential of this implementation to derive dense displacement fields with a computational time compatible with the camera images acquired every 2 h and with the size of the TerraSAR-X scenes covering 30 × 50 km2.