MATLAB: How to set black (pixel=0 or <20) to NaN in an image

image processingnanpixel value

Hi there, can anyone tell me how to convert black regions on grayscale image to NaN value? I appreciate any answers.

Best Answer

Let I be your matrix....read using imread
If you want to make pixels [0 20] to NaN..do this:
I(I>=0 & I<= 20) = NaN