I am trying to do stereo calibration in opencv using python, the opencv version is 2.4.8. For my code below, the cv2.calibrateCamera for left-side and right-side camera works well. However, for the result of cv2.stereoCalibrate function is wrong. And I could not figure out the reason. cameraMatrix1: array([[ 1., 0., 0.], [ 0., 1., 0.], [ 0., 0., 1.]]) cameraMatrix2: array([[ 1., 0., 0.], [ 0., 1., 0.], [ 0., 0., 1.]]) distCoeffs1: array([[ 0., 0., 0., 0., 0.]]) distCoeffs2: array([[ 0., 0., 0., 0., 0.]]) R: array([[ 1.00000000e+00, 1.94439107e-12, -1.43540965e-16], [ -1.94439107e-12, 1.00000000e+00, -1.73569059e-15], [ 1.43540965e-16, 1.73569059e-15, 1.00000000e+00]]) T: array([[ -8.72592313e-11], [ 2.32321701e-11], [ -6.12694770e-14]]) E: array([[ -7.48092314e-01, 3.95823749e+11, 1.50088513e+14], [ -3.95823749e+11, 2.08819986e-01, 5.63727287e+14], [ -1.50088513e+14, -5.63727287e+14, 1.00000000e+00]]) F: array([[ -7.48092314e-01, 3.95823749e+11, 1.50088513e+14], [ -3.95823749e+11, 2.08819986e-01, 5.63727287e+14], [ -1.50088513e+14, -5.63727287e+14, 1.00000000e+00]])
Following is my code for stereo calibrate:
import numpy as np import cv2 import glob
termination criteria
criteria = (cv2.TERM_CRITERIA_EPS + cv2.TERM_CRITERIA_MAX_ITER, 30, 0.001)
prepare object points, like (0,0,0), (1,0,0), (2,0,0) ....,(6,5,0)
objp = np.zeros((14*14,3), np.float32) objp[:,:2] = np.mgrid[0:14,0:14].T.reshape(-1,2)
Arrays to store object points and image points from all the images.
objpoints_left = [] # 3d point in real world space objpoints_right = [] imgpoints_left = [] # 2d points in image plane. imgpoints_right = []
images_left = glob.glob('ImageL*.jpg')
for fname in images_left: img_left = cv2.imread(fname) gray_left = cv2.cvtColor(img_left,cv2.COLOR_BGR2GRAY)
# Find the chess board corners
ret_left, corners_left = cv2.findChessboardCorners(gray_left, (14,14),None)
#print ret_left
# If found, add object points, image points (after refining them)
if ret_left == True:
objpoints_left.append(objp)
cv2.cornerSubPix(gray_left,corners_left,(20,20),(-1,-1),criteria)
imgpoints_left.append(corners_left)
# Draw and display the corners
cv2.drawChessboardCorners(img_left, (14,14), corners_left, ret_left)
img2_left=cv2.resize(img_left, (0,0), fx=0.4, fy=0.4)
cv2.imshow('img',img2_left)
cv2.waitKey(500)
cv2.destroyAllWindows()
ret_left, mtx_left, dist_left, rvecs_left, tvecs_left = cv2.calibrateCamera(objpoints_left, imgpoints_left, gray_left.shape[::-1],None,None)
images_right = glob.glob('ImageR*.jpg')
for fname in images_right: img_right = cv2.imread(fname) gray_right = cv2.cvtColor(img_right,cv2.COLOR_BGR2GRAY)
# Find the chess board corners
ret_right, corners_right = cv2.findChessboardCorners(gray_right, (14,14),None)
#print ret_right
# If found, add object points, image points (after refining them)
if ret_right == True:
objpoints_right.append(objp)
cv2.cornerSubPix(gray_right,corners_right,(20,20),(-1,-1),criteria)
imgpoints_right.append(corners_right)
# Draw and display the corners
cv2.drawChessboardCorners(img_right, (14,14), corners_right, ret_right)
img2_right=cv2.resize(img_right, (0,0), fx=0.4, fy=0.4)
cv2.imshow('img',img2_right)
cv2.waitKey(500)
cv2.destroyAllWindows()
ret_right, mtx_right, dist_right, rvecs_right, tvecs_right = cv2.calibrateCamera(objpoints_right, imgpoints_right, gray_right.shape[::-1], None, None)
retval,cameraMatrix1, distCoeffs1, cameraMatrix2, distCoeffs2, R, T, E, F=cv2.stereoCalibrate(objpoints_left, imgpoints_left, imgpoints_left, gray_left.shape[::-1])