# Find point coordinate in a projected rectangle

Hello OpenCV users.

I'm in front of a thought-it-was-simple problem, and as I am quite rusty concerning geometry and mathematics, I would like to request your help.

On the image below you can see a picture representing the problem

This entire image represent the picture I get from my camera.

In this image I suceed to detect 4 points (A,B,C,D), forming a rectangle.

-I know the coordinates(in pixels) of these 4 points in my camera view.

-I also know the real dimensions of the rectangle I'm trying to detect.

Considering a point F in my camera view, I would like to calculate its coordinate in the frame formed by A,B,C,D. How to do this with openCV ?