MATLAB: How to calculate the white area pixels amount

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how to calculate the white area pixels amount?

Best Answer

Try this:

numWhitePixels = nnz(binaryImage);

Other ways

numWhitePixels = sum(binaryImage(:));
whiteArea = bwarea(binaryImage);

Related Solutions

MATLAB: How to detect only object without background

Find out where all color channels are darker than some threshold, then and the masks and take the largest blob

% Extract the individual red, green, and blue color channels.
redChannel = rgbImage(:, :, 1);
greenChannel = rgbImage(:, :, 2);
blueChannel = rgbImage(:, :, 3);
% Threshold to create mask for each channel.
threshold = 20; % Whatever...
mask = (redChannel < threshold) & (greenChannel < threshold) & (blueChannel < threshold);
backgroundMask = bwareafilt(mask, 1); % Take largest blob
footMask = ~backgroundMask; % The inverse of the background mask.

MATLAB: Bwarea & area, white/black ratio

They use different algorithms. regionprops gives the number of pixels while bwarea gives some kind of weighted area that depends on the shape of the boundary. This is described in the documentation for bwarea

The white to black ratio is

totalPixels = numel(binaryImages);
numWhitePixels = sum(binaryImage(:));
numBlackPixels = totalPixels - numWhitePixels;
ratio = numWhitePixels  / numBlackPixels;

Best Answer

Related Solutions

MATLAB: How to detect only object without background

MATLAB: Bwarea & area, white/black ratio

Related Question