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

input image is grayscale image. how can i get black & white no. of pixels

Answer 1

[Nitin]

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);

[EM geo]

Does it do a count of white and black pixels?

[Image Analyst]

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(:));