i am trying to determine the bounding rectangle (position and rotation) for a mainly rectangular shaped contour using OpenCV and python. There is one problem: Parts of the background interfere with the rectangle.

Does anyone have an idea, what else, i could try?

I have tried the following:

• A closing with different kernel sizes and number of interations -> The rectangular shape was destroyed before all the noise was gone

• Iterating over the image and all possible 180 degrees of rotation and trying to find the rectangle position and rotation that contains the most white pixels. (This is possible since i know the size of the rectangle. But it was extremely slow and not that precise)

• Feature Matching (wasnt expecting much, and didnt work at all)

• Edge detection

• Contour Approximation with a Polygon with 4 Points

Testimages Images are the following:

• Testimage1
• Testimage2
• Testimage3
• Testimage4
• Testimage5

Many thanks for your help in advance!