# How to calculate gradient features of an image?

4 views (last 30 days)
Maninder on 22 Oct 2014
Commented: Munshida P on 25 Aug 2019
My code is:
figure, imshow(Gmag, []), title('Gradient magnitude') figure, imshow(Gdir, []), title('Gradient direction') title('Gradient Magnitude (Gmag) and Gradient Direction (Gdir) using Sobel method') figure; imshowpair(Gx, Gy, 'montage'); axis off; title('Directional Gradients, Gx and Gy, using Sobel method')
error is:
??? Error using ==> rdivide Integers can only be combined with integers of the same class, or scalar doubles.
Error in ==> gradient at 75 g(2:n-1,:) = (f(3:n,:)-f(1:n-2,:))./h(:,ones(p,1));
Guillaume on 22 Oct 2014
And what is your question exactly?

Guillaume on 22 Oct 2014
You left out the important bit of the error, which is the one that told you on which line of your code the error occurred. I assume it's the
line that gives you the error, since the 2nd argument to gradient must be a scalar value.
Munshida P on 25 Aug 2019
Munshida P on 25 Aug 2019
how to calulate the average gradient ?
i have calculated Gx,Gy,Gmag,Gdir

Munshida P on 24 Aug 2019
how to calculate average gradient of an image
Walter Roberson on 25 Aug 2019
average_gradient = sum(double(Gmag(:))) ./ ((size(Gmag,1)-1) .* ((size(Gmag,2)-1).*sqrt(2));
Munshida P on 25 Aug 2019
Thank you sir. I will try it now