Pixel values ruin with Calibration and/or Spekle filter

In processing chain, Calibration>Multilook> Train Correction, or Calibration>ML>Spk filt>TC, and saving in bigtiff geotiff for further analysis, I see that pixel values got to be between 0-0.3 while it is float 32. But excluding calibration and/or speckle filter, pixel values became nicely between zero to couple of hundreds.

Wondering why “Calibration” and or “Speckle Filter” ruin the pixel values unexpectedly?
normal? any advice?

Calibration produces sigma0 whose value is generally in range of [0, 1].

I agree with @junlu - the values are not ruined, just transformed.

You can check if everything is fine by logarithmising (right-click > linear to db) the values. If they result in a range between -35 and+5 db everything is fine.

Sigma0 image:

Sigma0 histogram:

Sigma0db image:


Sigma0db histogram:

1 Like

Thank you so much. It solved the problem.