Learning OpenCV 4 Computer Vision with Python 3 - Third Edition

Convex contours and the Douglas-Peucker algorithm

When working with contours, we may encounter subjects with diverse shapes, including convex ones. A convex shape is one where there are no two points within this shape whose connecting line goes outside the perimeter of the shape itself.

The first facility that OpenCV offers to calculate the approximate bounding polygon of a shape is cv2.approxPolyDP. This function takes three parameters:

• A contour.
• An epsilon value representing the maximum discrepancy between the original contour and the approximated polygon (the lower the value, the closer the approximated value will be to the original contour).
• A Boolean flag. If it is True, it signifies that the polygon is closed.

The epsilon value is ...