Using polygon affects my result

Dear all,
As my coherence and interferogram results has so much nose, unwrapping result was so bad because of this, I used polygon for cutting my area of interest that fringes and coherence are good on it and my unwrapping result is good now.


When I used polygon for cutting coherence and phase image. It changed colors in coherence image , interferogram image even histograms in left side and I think it can effect on amount of coherence too. What we can do now?
Please look at below images.

Interferogram before using polygon:

Interferogram after using polygon:

Coherence before using polygon:

coherence after using polygon:

i think it’s no wonder that the colours and histograms are changed because the color palette is now stretched over a completely different range of values. The reason for your altered histogram bins is that there are no longer so many values left.
This should be exactly what you get when you reduce rasters to smaller extents.

To check if everything went fine use the polygon as a ROI for a histogram calculation of your coherence. Compare this histogram to the one of your clipped image. Both should be the same. You can also use the statistics tool which additionally displays minimum, maximum and some other specifications which help you to directly compare both rasters.