generate-calibration-marker.py

import cv2
import numpy as np

paper_size = 2100, 2100
cross_len = 20
center = paper_size[0] // 2, paper_size[1] // 2

marker = np.ones(paper_size) * 255
cv2.circle(marker, center, 940, (180, 180, 180), thickness=2)
cv2.circle(marker, center, 600, (0, 0, 0), thickness=-1)
cv2.circle(marker, center, 380, (255, 255, 255), thickness=-1)
cv2.circle(marker, center, 190, (0, 0, 0), thickness=-1)
rectangle = ((center[0], center[1] - cross_len), (center[0], center[1] + cross_len))
cv2.rectangle(marker, *rectangle, (200, 200, 200), cross_len // 2)
rectangle = ((center[0] - cross_len, center[1]), (center[0] + cross_len, center[1]))
cv2.rectangle(marker, *rectangle, (200, 200, 200), cross_len // 2)
cv2.imwrite("marker.jpg", marker)