Normalized Cross Correlation for rgb image

Here is the code for to find normalized cross correlation between two images.

function NK = NormalizedCrossCorrelation(origImg, distImg)

origImg = double(origImg);
distImg = double(distImg);

NK = sum(sum(origImg .* distImg)) / sum(sum(origImg .* origImg));

But it works for grey scale images. When I run it for rgb image, error occurred: ??? Error using ==> mrdivide Inputs must be 2-D, or at least one input must be scalar.

Error in ==> NormalizedCrossCorrelation at 15 NK = sum(sum(origImg .* distImg)) / sum(sum(origImg .* origImg)); Can you please help me modify this code for rgb image. Thanks in advance.

[Mohammad Abouali]

Sorry, but that is not Normalized cross correlation even for a gray scale image.

[Nataliya]

Are you sure? Can you provide me the code for normalized cross correlation?

Answer 1

[Image Analyst]

See my attached demo of it.