Can some one give me an example of cross correlation's high value where template matches with image? I find it difficult to understand how result of cross correlation of a patch of image and image is high at matching point? what if patch contains small values and other non matching point contains very high values.
Please read this document here. If I understood your question clearly, then you need to take out the mean from the image. After that probably you would find cross-correlation for the matching patch.