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ChArUco calibration and detection from jpeg image files
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| #!/usr/bin/env python | |
| import cv2 | |
| import numpy as np | |
| import matplotlib.pyplot as plt | |
| import glob | |
| import random | |
| import sys | |
| aruco_dict = cv2.aruco.Dictionary_get(cv2.aruco.DICT_4X4_50) | |
| # Note: Following args don't work | |
| # board = cv2.aruco.CharucoBoard_create(8, 11, 0.015, 0.011, aruco_dict) | |
| board = cv2.aruco.CharucoBoard_create(11, 8, 0.015, 0.011, aruco_dict) | |
| def read_chessboards(frames): | |
| """ | |
| Charuco base pose estimation. | |
| """ | |
| all_corners = [] | |
| all_ids = [] | |
| for frame in frames: | |
| gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY) | |
| corners, ids, rejectedImgPoints = cv2.aruco.detectMarkers(gray, aruco_dict) | |
| if len(corners) > 0: | |
| ret, c_corners, c_ids = cv2.aruco.interpolateCornersCharuco(corners, ids, gray, board) | |
| # ret is the number of detected corners | |
| if ret > 0: | |
| all_corners.append(c_corners) | |
| all_ids.append(c_ids) | |
| else: | |
| print('Failed!') | |
| imsize = gray.shape | |
| return all_corners, all_ids, imsize | |
| def capture_camera(dev_num=0, num=1, mirror=False, size=None): | |
| frames = [] | |
| cap = cv2.VideoCapture(dev_num) | |
| while True: | |
| ret, frame = cap.read() | |
| if mirror is True: | |
| frame = cv2.flip(frame, 1) | |
| if size is not None and len(size) == 2: | |
| frame = cv2.resize(frame, size) | |
| # My config applies floating layout for windows named 'Java' | |
| cv2.imshow('Java', frame) | |
| k = cv2.waitKey(1) | |
| if k == 27: # Esc | |
| break | |
| elif k == 10 or k == 32: # Enter or Space | |
| frames.append(frame) | |
| print('Frame captured!') | |
| if len(frames) == num: | |
| break | |
| return frames | |
| def draw_axis(frame, camera_matrix, dist_coeff, board): | |
| corners, ids, rejected_points = cv2.aruco.detectMarkers(frame, aruco_dict) | |
| ret, c_corners, c_ids = cv2.aruco.interpolateCornersCharuco(corners, | |
| ids, | |
| frame, | |
| board) | |
| ret, p_rvec, p_tvec = cv2.aruco.estimatePoseCharucoBoard(c_corners, | |
| c_ids, | |
| board, | |
| camera_matrix, | |
| dist_coeff) | |
| cv2.aruco.drawAxis(frame, | |
| camera_matrix, | |
| dist_coeff, | |
| p_rvec, | |
| p_tvec, | |
| 0.1) | |
| # cv2.aruco.drawDetectedCornersCharuco(frame, c_corners, c_ids) | |
| # cv2.aruco.drawDetectedMarkers(frame, corners, ids) | |
| # cv2.aruco.drawDetectedMarkers(frame, rejected_points, borderColor=(100, 0, 240)) | |
| print('Translation : {0}'.format(p_tvec)) | |
| print('Rotation : {0}'.format(p_rvec)) | |
| print('Distance from camera: {0} m'.format(np.linalg.norm(p_tvec))) | |
| return frame | |
| def main(): | |
| video_dev = int(sys.argv[1]) | |
| frames = capture_camera(video_dev, 10) | |
| if len(frames) == 0: | |
| print('No frame captured') | |
| sys.exit(1) | |
| all_corners, all_ids, imsize = read_chessboards(frames) | |
| ret, camera_matrix, dist_coeff, rvec, tvec = cv2.aruco.calibrateCameraCharuco( | |
| all_corners, all_ids, board, imsize, None, None | |
| ) | |
| print('> Camera matrix') | |
| print(camera_matrix) | |
| print('> Distortion coefficients') | |
| print(dist_coeff) | |
| test_frame = capture_camera(video_dev, 1)[0] | |
| test_frame = draw_axis(test_frame, camera_matrix, dist_coeff, board) | |
| cv2.imwrite('output.jpg', test_frame) | |
| # My config applies floating layout for windows named 'Java' | |
| cv2.imshow('Java', test_frame) | |
| cv2.waitKey(0) | |
| if __name__ == '__main__': | |
| main() |
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