Lee Refined Speckle Filter "Mask_Valid_Pixels.BMP" file not created


After following online tutorials for processing Sentinel-1 imagery, I am getting stuck at the step where I apply the Lee Refined Speckle Filter. I believe it is supposed to produce a file called “Mask_Valid_Pixels.BMP”, but that file is not being produced. Does anyone know why this file is not being created, and what I should be doing differently to create it? The next step is to run the Alpha Decomposition, which isn’t working, I assume as a result of the .BMP file not being created.

Thank you!

I would be helpful to know the URL for the tutorial you are following.

Of course! The speckle filter is around 14:18.