S. Leprince, S. Barbot, F. Ayoub, J.P. Avouac, "Automatic, Precise, Ortho-rectification and Coregistration for satellite Image Correlation, Application to Ground Deformation Measurement", IEEE Trans. Geosc. Rem. Sens., in press, 2006

Abstract - We describe a procedure to accurately measure ground deformations from optical satellite images. Precise orthorectification is obtained thanks to an optimized model of the imaging system where look directions are linearly corrected to compensate for attitude drifts, and sensor orientation uncertainties are accounted for. We compute both direct and inverse projection matrices for each of which a rigorous resampling is proposed. The irregular resampling problem is explicitly addressed to avoid introducing aliasing in the ortho-rectified images. Image registration and correlation is achieved with a new iterative, unbiased processor that estimates the phase plane in the Fourier domain for sub-pixel shift detection. Without using supplementary data, raw images are wrapped onto the digital elevation model, and co-registered with a 1/50 pixel accuracy. The procedure applies to images from any pushbroom imaging system. We analyze its performance using SPOT images in the case of a null test (no co-seismic deformations) and in the case of large co-seismic deformations due to the Mw 7.1 Hector Mine, California, earthquake of 1999. The proposed technique would also allow precise co-registration of images for the measurement of surface displacements due to ice-flow or geomorphic processes, or for any other change detection applications. A complete software package, COSI-corr, is available for download from the Caltech Tectonics Observatory Web-site.