Azimuth Filtering (InSAR operator) | ![]() |
This operator filters the spectras, of stack of SLC images, in the azimuth direction. This is an optional step in the interferometric processing chain. The part of the spectras do that does not overlap with the spectrum of the slave is filtered out. This non overlap is due to the selection of a Doppler centroid frequency in the SAR processing, which normally is not equal for master and slave image.
This step can in general best be performed after the coregistration. (The offset in range direction is used to evaluate the polynomial for the Doppler Centroid frequency.)
Operator performs filtering of all images in the stack at the same time. However, if multiple slave images are present in the stack, only slave images will be filtered, and master image will remain unfiltered (all slaves coregistered on the same master image). This approach has the advantage that for each interferogram of the stack a separate set of master images is created, effectively saving the disk storage space and making the processing more efficient. The disadvantage of not filtering the master is that a small part of the spectrum of the master is not shared with the slave spectrum, yielding a minor loss of coherence in the interferogram.
Source Bands are set of coregistered bands of the complex product.
Output Bands are set of bands with spectras filtered in azimuth direction.