how to encode and decode negative pixel to positive pixel in matlab ?

hi, I want to ask. I have 512x512 image and I want to calculate the entropy. But, it has some error because the pixel contains negative value. Has anybody in here know how to do Matlab code to convert negative pixel to positive pixel and decode it back? please help me

Answer 1

[Image Analyst]

Try this:

negPixels = grayImage < 0;
grayImage(negPixels) = 0; % or 1 or whatever you want.

[Walter Roberson]

Or more simply,

max(0, grayImage)

[Image Analyst]

Actually:

grayImage = max(0, grayImage);

[nur aqila]

thank you !