I am unable to rotate or deskew the image it is not rotating correctly in opencvsharp

so, which problem does it solve, and why cut off at pi/4 ?

indeed, using the angle from a rotatedrect has a few problems:

  • angle is derived via atan , so pole at ±pi/2
  • implementation changed (somewhere about 4.3)
    (today, you get the angle towards the longer one of two rect edges, so the input is always in [-1,1])