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Drashti
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how to get black & white pixels count from grayscale image...???

Asked by Drashti
on 1 May 2014
Latest activity Commented on by Image Analyst
on 26 Oct 2018
input image is grayscale image. how can i get black & white no. of pixels

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1 Answer

Answer by Nitin
on 1 May 2014

black corresponds to zeros in your image and white corresponds to ones if your image is double format.
I_double = im2double(img);
% Find black pixels
b = find(I_double==0);
% Find white pixels
w = find(I_double==1);

  2 Comments

Does it do a count of white and black pixels?
No it does not.
You'd have to do
numBlackPixels = numel(b); % Count the number of linear indexes returned.
numWhitePixels = numel(w);
For a uint8 image, you'd do
pureWhitePixels = grayImage == 255;
numberOfWhitePixels = sum(pureWhitePixels(:));
pureBlackPixels = grayImage == 0;
numberOfBlackPixels = sum(pureBlackPixels(:));

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