MATLAB: Counting black pixels in a binary image

image processingImage Processing Toolboximage segmentation

How can I write a code to count the black pixels and the white pixels in a binary image?

Best Answer

Let's say you have a binary image B. You can get the number of black pixels by:

numBlack=nnz(~B);

and the number of white pixels by:

numWhite=nnz(B);

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MATLAB: How can i get no of white pixels in a binary image

The color image you show has very few white pixels.

If you have converted it to binary then

number_of_white_pixels = nnz(TheBinaryImage);

MATLAB: Counting black and white pixels

It is line 33 of the attached file that is causing the problem

 message = sprintf('Done!\nTotal number of pixels = %d\nBlack pixels = %d = %.1f%%\nWhite pixels = %d = %.1f%%', ...totalNumberOfPixels, numberOfBlackPixels, percentBlackPixels, ...numberOfWhitePixels, percentWhitePixels);

Note the ellipsis (...) which is used in MATLAB to indicate that code on the subsequent line follows code from the previous line. For example

 m=42;
 fprintf('this is a test of printing of the number %d\n',...
         m);

is equivalent to

 m=42;
 fprintf('this is a test of printing of the number %d\n', m);

In your code, there are two instances of the ellipsis and so either they should be removed, or line breaks should be added. If doing the latter, then the above line of code becomes three lines of code as

message = sprintf('Done!\nTotal number of pixels = %d\nBlack pixels = %d = %.1f%%\nWhite pixels = %d = %.1f%%', ... 
  totalNumberOfPixels, numberOfBlackPixels, percentBlackPixels, ...
  numberOfWhitePixels, percentWhitePixels);

Just replace line 33 with the above (or simply remove the ellipses) and see what happens!

Best Answer

Related Solutions

MATLAB: How can i get no of white pixels in a binary image

MATLAB: Counting black and white pixels

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