OpenCV 3 Computer Vision with Python Cookbook

How to do it...

1. Import the modules:

import cv2import numpy as npimport matplotlib.pyplot as plt

2. Draw a test image—a white ellipse with the center at point (320, 240), on a black background:

image = np.zeros((480, 640), np.uint8)cv2.ellipse(image, (320, 240), (200, 100), 0, 0, 360, 255, -1)

3. Compute the moments and print their values:

m = cv2.moments(image)for name, val in m.items():    print(name, '\t', val)

4. Perform a simple test to check whether the computed moments make sense, compute the center of the mass of the image using its first moments. It must be close to the center of the ellipse we specified above:

print('Center X estimated:', m['m10'] / m['m00'])print('Center Y estimated:', m['m01'] / m['m00'])