OpenCV 3.x with Python By Example - Second Edition

Contour analysis and shape matching

Contour analysis is a very useful tool in the field of computer vision. We deal with a lot of shapes in the real world, and contour analysis helps in analyzing those shapes using various algorithms. When we convert an image to grayscale and threshold it, we are left with a bunch of lines and contours. Once we understand the properties of different shapes, we will be able to extract detailed information from an image.

Let's say we want to identify the boomerang shape in the following image:

In order to do that, we first need to know what a regular boomerang looks like:

Now, using the preceding image as a ...