Perhaps I'm misunderstanding this. But why is a CNN necessary for predicting the turning angle? Seems like OpenCV would be sufficient (assuming sufficient contrast between the line and the floor). Grab image, threshold, find the largest contour around the line, grab its minAreaRect() and from that calculate the angle.
Editing to add -- this is still a cool project. I don't mean to detract from it by pointing out that I think it could be done without the AI piece.
Editing to add -- this is still a cool project. I don't mean to detract from it by pointing out that I think it could be done without the AI piece.