How to find the number of pixels with intensity

I'm trying to find the histogram of an image. I'm supposed to use loops to calculate it. So far, my code is

histogram = = zeros(256,1,'int16');
for j = 0 : 255
histogram(j + 1) = number of pixels with intensity j
end

The problem I'm having is that I'm not sure how to find the number of pixels with intensity j. I know that I should use either the find() or sum() function, but I don't know how to format that part of the code

Answer 1

[Matt J]

One way,

histogram(j + 1) = nnz(yourImage==j);

Or,

histogram(j + 1) = sum(yourImage(:)==j);

[Davidson Bock]

ok thanks! I'm very new to MatLab, when I want to save the part where I did the coding, do I click "Save Workspace"?

[Matt J]

You're welcome, but please Accept-click the answer to confirm that it resolved your issue.

As for saving, you should write the code in the Editor Window and use the file save button on the toolbar