Subscript indices must either be real positive integers or logicals.

I got this error when i found the mean of a histogram. I have used

 [pixelCount grayLevels] = imhist(Im); 
 meanOriginal = sum(pixelCount .* grayLevels) / sum(pixelCount);

[Stephen23]

Have you defined a varibale named sum ?

Please tell us exactly the output of

which sum -all

Answer 1

[Walter Roberson]

You have probably named a variable sum, interfering with the use of the sum function.