I am a newbie to the InSAR technique, and I am working with this currently. When submitting jobs, I have to set the values of Azimuth Coherence Window Size, Range Coherence Window Size, Azimuth Multilook Factor and Range Multilook factor. Indeed, I am not really clear about the meaning and the effect of those parameters on the results. Additionally, how can I know what the good values for those are?
Interferometric coherence is a measure for the relation of both images. It is computed for a moving window because a pixel-by-pixel comparison is not suitable because of smaller signal variation. Range size is the number of pixels in looking direction of the radar system and azimuth size is the number of pixels in flight direction of the radar system. They are defined independently, because the spatial resolution is different in azimuth and range direction for SAR images in slant geometry. Too large windows will lead to overall high agreement between both images without highlighting their differnce. But as this is a scale-dependent issue, best possibility is to compute and compare different window sizes for the computation. This could also help to distinguish objects and surface of different dimensions.