The polarimetric matrix elements of C11 and C22 become empty after polarimetric speckle filtering

Hello everyone,

I have processed output of S1A_IW_SLC__1SDV_20201009T230130_20201009T230157_034726_040BA7_F04D.SAFE image for Haiti. I followed the steps of Apply orbit file, Split, Calibrate, Geo-coding (I wanted a combined output of IW2 and IW3 sub swaths), deburst, polarimetric matrices, Multi look, Speckle filter, decomposition and terrain correction. How ever, after speckle filtering C11 and C22 images become empty where C12 real and Imagery are not. Can anyone please explain me my mistake or the reason here. Thank you!

are you sure that the data was still valid after multi-looking?

As Sentinel-1 is dual-pol only, not all polarimetric matrices can be calculated

Hello ABraun,

I calculated C2, which is for dual polarization. I processed another image (S1A_IW_SLC__1SDV_20201007T104732_20201007T104758_034689_040A5C_519F.SAFE) for the same study area. That one is ok. It generates entropy, anisotropy and alpha. The difference between these two images is that 20201007 image has the study area with in a one sub swath, 20201009 image contains the study area in two sub swaths. The only process that varied was “geocoding” between them.

This is the C11 output for Multi looking step.

C11 becomes empty like this after speckle filtering.

Thank you very much.

Please try to apply the speckle filtering after Multi Looking and then calculate the C matrix afterwards (sometimes the polarimetric speckle filter automatically outputs C matrix data)