OpenCV 3 Computer Vision with Python Cookbook

How it works...

There is a special function in OpenCV to measure the smallest distance from a point to a contour. It's called cv2.pointPolygonTest. It takes three arguments, and returns the measured distance. The arguments are a contour, a point, and a Boolean flag, whose purpose we will discuss a little later. The resulting distance can be positive, negative, or equal to zero, which corresponds to inside the contour, outside the contour, or on a contour point position. The last Boolean argument determines whether our function returns the exact distance or only an indicator with a value (+1; 0; -1). The sign of the indicator has the same meaning as the mode that computes the exact distance.

As a result of the code, you will get something ...