MATLAB: Median gray level value

Question

Hi there,

How can I find the median gray level of non-zero valued pixels in an image?

I am working on mammograms that have lot of zero valued pixels, but it dosent matter.

Thanks

Answer 1

Hi Faraz, you can simply make a mask of the pixels you don't want to include, then take the median of all the others:

Im = randi(10,512,512) - 1;      % Sample image with some 0s
zeroMask = Im==0;                % Mask of 0s
medValue = median(Im(~zeroMask)) % Median of the rest

Or, in one command:

medValue = median(Im(Im>0));