OpenCV 4 with Python Blueprints - Second Edition

Distinguishing between different causes of convexity defects

The trick is to look at the angle between the farthest point from the convex hull point within the defect (farthest_pt_index) and the start and endpoints of the defect (start_index and end_index, respectively), as illustrated in the following screenshot:

In the previous screenshot, the orange markers serve as a visual aid to center the hand in the middle of the screen, and the convex hull is outlined in green. Each red dot corresponds to the point farthest from the convex hull (farthest_pt_index) for every convexity defect detected. If we compare a typical angle that belongs to two ...