Extract similar area of two images

Question

I wonder that extracting similar area of images is possible. if it is possible,i am going to find insigne of copmany which created it.

There are two images below. The red rectangles in the images are that i try to find area. The program is going to find similar area comparing images. I tried to find it using opencv,but i couldn't do it.

Answer 1

First thing in mind:

1. Convert images to grayscale
2. Divide image into small areas (patches)
3. Each patch should be labelled as 1 if entropy of image is high and 0 if low (to discard patches without letters)
4. For two images, compare all patches across images based on:
   • Histogram on sobel image (Bhattacharya distance is normalized)
   • Correlation (Minmax normalization)
   • Advanced descriptors (like SIFT) (L2 normalization)
5. Min distance wins.

You can narrow down the '1' patches with a text detector (Algorithm to detect presence of text on image).