OpenCV 3 Computer Vision with Python Cookbook

How to do it...

1. Import the modules:

import cv2import matplotlib.pyplot as plt

2. Load the test image with a chessboard:

image_chess = cv2.imread('../data/chessboard.png')

3. Detect the chessboard pattern:

found, corners = cv2.findChessboardCorners(image_chess, (6, 9))assert found == True, "can't find chessboard pattern"

4. Draw the detected pattern:

dbg_image_chess = image_chess.copy()cv2.drawChessboardCorners(dbg_image_chess, (6, 9), corners, found);

5. Load the test image with a circle grid pattern:

image_circles = cv2.imread('../data/circlesgrid.png')

6. Detect the circle grid pattern:

found, corners = cv2.findCirclesGrid(image_circles, (6, 6), cv2.CALIB_CB_SYMMETRIC_GRID)assert found == True, "can't find circles grid pattern"

7. Draw the detected ...