Remove unwanted regions in binary image

I have the following input image.

I want to remove the unwanted regions highlighted with red ellipses. This binary image can be tilted at any angle. Hence, counting the white pixels in each row and applying thresholding didn't work for tilted image.

After removing unwanted regions, I want to reduce the thickness of this rectangle to single pixel thickness. I want to only consider the black pixels that are next to the white pixels and remove the outer black pixels. I have tried thin and skel morphological operations but didn't work for me.

Thanks in advance,

Syed

Answer 1

[Image Analyst]

Use bwconvhull().