In a HipChat conversation on Dec 1st Robert Lupton told me:
This is the classic use for a subimage: center = maskedIm[20:-20, 20:-20]
Changes to center (spelt in Usan for your sake) will change maskedIm, but if all you want is your subimage you're in business. Or center = maskedIm[20:-20, 20:-20].clone() if you want a copy
In a HipChat conversation on Dec 1st Robert Lupton told me:
This is the classic use for a subimage: center = maskedIm[20:-20, 20:-20]
Changes to center (spelt in Usan for your sake) will change maskedIm, but if all you want is your subimage you're in business. Or center = maskedIm[20:-20, 20:-20].clone() if you want a copy