How to calculate no. of pixels having value greater than a particular RGB value?

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Dhrubajyoti Das
Dhrubajyoti Das 2013-11-6
评论： Guillaume 2018-11-8
I want to calculate the no. of pixels having value greater than a particular RGB value for eg. lets say 180. (pic(mm,nn,1) > 180 && pic(mm,nn,2) > 180 && pic(mm,nn,3) > 180).

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回答（3 个）

Azzi Abdelmalek
Azzi Abdelmalek 2013-11-6
编辑：Azzi Abdelmalek 2013-11-6
idx=pic>180
out=sum(idx(:))
Image Analyst
Image Analyst 2013-11-6
% Extract the individual red, green, and blue color channels and threshold them.
binaryR = rgbImage(:, :, 1) > 180;
binaryG = rgbImage(:, :, 2) > 180;
binaryB = rgbImage(:, :, 3) > 180;
% AND the binary images together to find out where ALL THREE are > 180.
binaryImage = binaryR & binaryG & binaryB;
% Count the number of pixels where it's true that all 3 are > 180;
pixelCount = sum(binaryImage(:));
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Anbarasan Rajan
Anbarasan Rajan 2018-11-8
pixelCount=sum(binaryImage(:)); i think this will only give us the total pixel intensity. for example, if 10 pixels are having the intensity of 50, this comment will give us 500 which is the total intensity value of the pixels present in thet image.
if i'm wrong please let me know.
Guillaume
Guillaume 2018-11-8
"if i'm wrong please let me know."
You're wrong. binaryImage is 1 when all 3 channels of the pixel is above the threshold, and 0 otherwise. Hence the sum is the number of pixels, Image Analyst could have used nnz instead:
pixelCount = nnz(binaryImage);

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suganya sri
suganya sri 2017-11-13
how to find pixel value in somelocation, pls anybody help me

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