Minimising the tie patch window size for SAR image co-registration

Owing to the presence of relatively large amounts of noise, coregistration of synthetic aperture radar (SAR) images typically involves matching of local area based ´tie patches´ rather than feature based ´tie points´. Some applications require small tie patch windows, e.g. stereo SAR. Small tie patch windows, however, can lead to poor estimates of the local co-registration parameters. A procedure to minimise the tie patch window size while retaining ´confidence´ in the local co-registration result is proposed. Background theory to the procedure and the results of an experimental study are presented.