How to counts matched object from main image with the template sub-Image

I have a task where I should count numbers of suits(diamonds, clubs, ...) in a set of playing cards image. I have created a template sub-image for diamond from my original image for example, using imcrop in Matlab. I have also converted both Original or target Image in grayscale. I'm trying to find the match of the sub-image in the target image and counts the corresponding diamonds in the target image.

Does anyone have a suggestion?

I try to use normxcorr2 I got a plot where I can see the area with highest peak, but I don't have any ideas how to compute this.

Any suggestions of algorithms.

Thank you.

Answer 1

[Jakob]

Using normxcorr2 will give you the point of highest correlation between image and template.

        % Perform registration
        reg = normxcorr2(t,sI);

        % find peaks and location and offset
        [dy,dx] = find(reg== max(reg(:)));

Where t is the template and sI is the search image. You can then find the offset with:

yoffSet = dy-size(t,1);
xoffSet = dx-size(t,2);

P(yoffSet+1,yoffSet+1) is the point in the sI where the template starts.