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

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).

Answer 1

[Azzi Abdelmalek]

idx=pic>180
out=sum(idx(:))

Answer 2

[Image Analyst]

% 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(:));

[Image Analyst]

By the way, why not just convert to gray scale immediately by taking one of the color channels? All the channels look identical anyway.

[Image Analyst]

Dhrubajyoti, did it work for you?

[Anbarasan Rajan]

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]

"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);

Answer 3

[suganya sri]

how to find pixel value in somelocation, pls anybody help me

[Image Analyst]

pixelValue = impixel(yourImage, row, column);