Find the corners of a deformed rectangle?

Question

I am trying to make a program that automatically corrects the perspective of a rectangle. I have managed to get the silhouette of the rectangle, and have the code to correct the perspective, but I can't find the corners. The biggest problem is that, because it has been deformed, I can't use the following "code": c1 = min(x), min(y) c2 = max(x), min(y) c3 = min(x), max(y) c4 = max(x), max(y) This wouldn't work with this situation (X represents a corner): X0000000000X .00000000000 ..X000000000 .....0000000 ........0000 ...........X Does anyone know how to do this?

Answer 1

Use distance and slope formulas.

The rectangles has opposite sides parallel and equal, so their distances and slopes should be the same.

Adjacent sides should be perpendicular, so their slopes should be negative reciprocals.

Get two points on each side, and derive the line equations for each side.

Then to get the corners, you find where those lines intersect