I am trying to write a function for the Gamma Correction, this is what I have so far. the problem is the intensities of the output image is either 0 or 255. what am I doing wrong?
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Reihaneh Khoshghadam
on 24 Oct 2018
Commented: Reihaneh Khoshghadam
on 24 Oct 2018
function adjust_im= Gamma_c(im, y, c)
rows = size(im,1);
cols = size(im,2);
mat= zeros(rows,cols,class(im));
for r=1: rows
for co=1: cols
pixel = im(r,co);
p1 = double(pixel/255);
p2 = double(c*((double(p1))^y));
p3 = double(p2*255);
mat(r,co) = round(p3);
end
end
adjust_im= mat;
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Accepted Answer
Adam
on 24 Oct 2018
Edited: Adam
on 24 Oct 2018
double(pixel/255)
will divide pixel by 255 then convert to a double. Assuming your image is an 8-bit integer data type this is not what you want as it will use integer division with truncation so everything apart from 255 will become 0. Use
pixel = double( im(r,co) );
or convert the whole image to double before the for loop (probably more efficient) and then you should not need all the other casts to double that you have.
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