问题
I have two sets of corresponding points from two images. I have estimated the Essential matrix which encodes the transformation between the cameras:
E, mask = cv2.findEssentialMat(points1, points2, 1.0)
I've then extracted the rotation and translation components:
points, R, t, mask = cv2.recoverPose(E, points1, points2)
But how do I actually get the cameras matrices of the two cameras so I can use cv2.triangulatePoints
to generate a little point cloud?
回答1:
Here is what I did:
Input:
pts_l - set of n 2d points in left image. nx2 numpy float array
pts_r - set of n 2d points in right image. nx2 numpy float array
K_l - Left Camera matrix. 3x3 numpy float array
K_r - Right Camera matrix. 3x3 numpy float array
Code:
# Normalize for Esential Matrix calaculation
pts_l_norm = cv2.undistortPoints(np.expand_dims(pts_l, axis=1), cameraMatrix=K_l, distCoeffs=None)
pts_r_norm = cv2.undistortPoints(np.expand_dims(pts_r, axis=1), cameraMatrix=K_r, distCoeffs=None)
E, mask = cv2.findEssentialMat(pts_l_norm, pts_r_norm, focal=1.0, pp=(0., 0.), method=cv2.RANSAC, prob=0.999, threshold=3.0)
points, R, t, mask = cv2.recoverPose(E, pts_l_norm, pts_r_norm)
M_r = np.hstack((R, t))
M_l = np.hstack((np.eye(3, 3), np.zeros((3, 1))))
P_l = np.dot(K_l, M_l)
P_r = np.dot(K_r, M_r)
point_4d_hom = cv2.triangulatePoints(P_l, P_r, np.expand_dims(pts_l, axis=1), np.expand_dims(pts_r, axis=1))
point_4d = point_4d_hom / np.tile(point_4d_hom[-1, :], (4, 1))
point_3d = point_4d[:3, :].T
Output:
point_3d - nx3 numpy array
来源:https://stackoverflow.com/questions/33906111/how-do-i-estimate-positions-of-two-cameras-in-opencv