How to find white bordered rectangle in an image?

  deep-learning, image-processing, opencv, python, python-3.x

I’m trying to get the coordinate of the white-bordered rectangle in image. The traditional approach is to find contours to find all the rectangles present in the image but I want to get only with certain bordered color like in the below picture image

How can I get the coordinates of white bordered rectangle only using opencv?
any suggestions on this very helpful, thanks

Source: Python-3x Questions