Mastering OpenCV 4 with Python

Some object features based on moments

As previously discussed, moments are features computed from contours allowing a geometrical reconstruction of the object. Despite not having a direct understandable geometrical meaning, some interesting geometrical properties and parameters can be calculated based on moments.

In contours_analysis.py, we will first calculate the moments for a detected contour and, afterwards, some object features will be computed:

M = cv2.moments(contours[0])print("Contour area: '{}'".format(cv2.contourArea(contours[0])))print("Contour area: '{}'".format(M['m00']))

As you can see, the moment m00 gives the area of the contour, which is equivalent to function cv2.contourArea(). In order to calculate the centroid of the ...