histogram plot not working for my image

Hi eveyone, I originally had a .tiff image (CMYK format) that I converted to RGB. I then converted to gray scale. On the grayscale image, I tried to plot a histogram of the data but returned the following error in matlab:

    Error using  .* 
    Integers can only be combined with integers
    of the same class, or scalar doubles.

Let me know if you would like me to provide my code. The format that my RGB image is an uint8.

Thanks for reading.

[Zahra Saman]

Please any one help me in this problem

Answer 1

[Image Analyst]

Then the grayscale image should also most likely be an uint8 array if you just took one color channel or used rgb2gray(). Which histogram function did you use? Did you do something like this:

% Let's compute and display the histogram.
[pixelCount grayLevels] = imhist(grayImage);
bar(grayLevels, pixelCount);
grid on;
title('Histogram of gray scale image', 'FontSize', 15);
xlim([0 grayLevels(end)]); % Scale x axis manually.

If you did something different (which I guess you must have, because your code doesn't work, while mine does), then you'll have to let us see your code.

[u-will-neva-no]

Thanks! My problem was that i wasn't using imhist() (I obtained the error message using hist). Your answer helped to show that I was on the right line (to use imhist) and it also helped for making the appearance of my plot to look better. Thank again!

[Matthew Gill]

I wasn't either! Good question and thanks for answer!

[Matthew Gill]

Actually, I was also setting histogram = to something