Plot nonlinear correlation between two images

Hello,

I need to plot nonlinear correaltion between two images and if the images are same we get to see a sharp peak in the centre.

The formulation is : abs ( IFT( {FT(img1) FT(img2)} x {FT(img1) FT(img2)} / abs(FT(img1) FT(img2)) ) ).^2

can somebody help me realize the code to do this.

The image on left is when two images are same and o right is when they are different.

Thanks