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Thebinary110 325e30db1d calib: expose calibrateHandEye and calibrateRobotWorldHandEye to Python
Both functions are fully implemented and documented but were tagged
CV_EXPORTS instead of CV_EXPORTS_W, so they were unreachable from
Python (and Java/JS) bindings. They use only bindable types
(InputArrayOfArrays, OutputArray, plain enums), so this is a pure
binding-exposure fix, not a behavior change.

Adds Python regression tests for both functions using synthetic
hand-eye data that satisfies the documented AX=XB (calibrateHandEye)
and AX=ZB (calibrateRobotWorldHandEye) relations, verifying the
recovered transform matches the synthetic ground truth.

Verified locally: built opencv_python3 bindings from this branch and
confirmed cv2.calibrateHandEye / cv2.calibrateRobotWorldHandEye are
now present and both new tests pass against synthetic ground-truth
poses.
2026-07-24 05:18:18 +05:30

177 lines
7.1 KiB
Python
Executable File

#!/usr/bin/env python
'''
camera calibration for distorted images with chess board samples
reads distorted images, calculates the calibration and write undistorted images
'''
# Python 2/3 compatibility
from __future__ import print_function
import numpy as np
import cv2 as cv
from tests_common import NewOpenCVTests
class calibration_test(NewOpenCVTests):
def test_calibration(self):
img_names = []
for i in range(1, 15):
if i < 10:
img_names.append('samples/data/left0{}.jpg'.format(str(i)))
elif i != 10:
img_names.append('samples/data/left{}.jpg'.format(str(i)))
square_size = 1.0
pattern_size = (9, 6)
pattern_points = np.zeros((np.prod(pattern_size), 3), np.float32)
pattern_points[:, :2] = np.indices(pattern_size).T.reshape(-1, 2)
pattern_points *= square_size
obj_points = []
img_points = []
h, w = 0, 0
for fn in img_names:
img = self.get_sample(fn, 0)
if img is None:
continue
h, w = img.shape[:2]
found, corners = cv.findChessboardCorners(img, pattern_size)
if found:
term = (cv.TERM_CRITERIA_EPS + cv.TERM_CRITERIA_COUNT, 30, 0.1)
cv.cornerSubPix(img, corners, (5, 5), (-1, -1), term)
if not found:
continue
img_points.append(corners.reshape(-1, 2))
obj_points.append(pattern_points)
# calculate camera distortion
rms, camera_matrix, dist_coefs, _rvecs, _tvecs = cv.calibrateCamera(obj_points, img_points, (w, h), None, None, flags = 0)
eps = 0.01
normCamEps = 10.0
normDistEps = 0.05
cameraMatrixTest = [[ 532.80992189, 0., 342.4952186 ],
[ 0., 532.93346422, 233.8879292 ],
[ 0., 0., 1. ]]
distCoeffsTest = [ -2.81325576e-01, 2.91130406e-02,
1.21234330e-03, -1.40825372e-04, 1.54865844e-01]
self.assertLess(abs(rms - 0.196334638034), eps)
self.assertLess(cv.norm(camera_matrix - cameraMatrixTest, cv.NORM_L1), normCamEps)
self.assertLess(cv.norm(dist_coefs - distCoeffsTest, cv.NORM_L1), normDistEps)
def test_projectPoints(self):
objectPoints = np.array([[181.24588 , 87.80361 , 11.421074],
[ 87.17948 , 184.75563 , 37.223446],
[ 22.558456, 45.495266, 246.05797 ]], dtype=np.float32)
rvec = np.array([[ 0.9357548 , -0.28316498, 0.21019171],
[ 0.30293274, 0.9505806 , -0.06803132],
[-0.18054008, 0.12733458, 0.9752903 ]], dtype=np.float32)
tvec = np.array([ 69.32692 , 17.602057, 135.77672 ], dtype=np.float32)
cameraMatrix = np.array([[214.0047 , 26.98735 , 253.37799 ],
[189.8172 , 10.038101, 18.862494],
[114.07123 , 200.87277 , 194.56332 ]], dtype=np.float32)
distCoeffs = distCoeffs = np.zeros((4, 1), dtype=np.float32)
imagePoints, jacobian = cv.projectPoints(objectPoints, rvec, tvec, cameraMatrix, distCoeffs)
self.assertTrue(imagePoints is not None)
self.assertTrue(jacobian is not None)
def test_sampsonDistance_valid2D(self):
pt1 = (np.random.rand(3, 10) * 256).astype(np.float64)
pt2 = (np.random.rand(3, 10) * 256).astype(np.float64)
F = (np.random.rand(3, 3) * 256).astype(np.float64)
dist = cv.sampsonDistance(pt1, pt2, F)
self.assertTrue(isinstance(dist, (float, np.floating)))
self.assertGreaterEqual(dist, 0.0)
@staticmethod
def _random_rt():
# random rotation (axis-angle) + random translation
axis = np.random.uniform(-1, 1, 3)
axis /= np.linalg.norm(axis)
angle = np.random.uniform(0.2, 1.0) * (1 if np.random.rand() > 0.5 else -1)
rvec = (axis * angle).astype(np.float64)
R, _ = cv.Rodrigues(rvec)
t = np.random.uniform(-100, 100, 3).astype(np.float64)
return R, t
@staticmethod
def _to_T(R, t):
T = np.eye(4)
T[:3, :3] = R
T[:3, 3] = t
return T
def test_calibrateHandEye(self):
# Ground truth camera-to-gripper transform (what calibrateHandEye should recover)
R_cam2gripper_gt, t_cam2gripper_gt = self._random_rt()
X = self._to_T(R_cam2gripper_gt, t_cam2gripper_gt)
# Arbitrary fixed target-to-base transform (the calibration board doesn't move)
R_target2base, t_target2base = self._random_rt()
Wt = self._to_T(R_target2base, t_target2base)
n_poses = 10
Rs_gripper2base, ts_gripper2base = [], []
Rs_target2cam, ts_target2cam = [], []
for _ in range(n_poses):
R_g2b, t_g2b = self._random_rt()
G = self._to_T(R_g2b, t_g2b)
# Consistent synthetic data: Wt == G @ X @ T_target2cam for every pose
T_target2cam = np.linalg.inv(X) @ np.linalg.inv(G) @ Wt
Rs_gripper2base.append(R_g2b)
ts_gripper2base.append(t_g2b)
Rs_target2cam.append(T_target2cam[:3, :3])
ts_target2cam.append(T_target2cam[:3, 3])
R_cam2gripper, t_cam2gripper = cv.calibrateHandEye(
Rs_gripper2base, ts_gripper2base, Rs_target2cam, ts_target2cam)
self.assertLess(cv.norm(R_cam2gripper - R_cam2gripper_gt, cv.NORM_L1), 1e-3)
self.assertLess(cv.norm(t_cam2gripper.flatten() - t_cam2gripper_gt, cv.NORM_L1), 1e-3)
def test_calibrateRobotWorldHandEye(self):
# Ground truth outputs (what calibrateRobotWorldHandEye should recover)
R_base2world_gt, t_base2world_gt = self._random_rt()
X = self._to_T(R_base2world_gt, t_base2world_gt)
R_gripper2cam_gt, t_gripper2cam_gt = self._random_rt()
Z = self._to_T(R_gripper2cam_gt, t_gripper2cam_gt)
n_poses = 10
Rs_world2cam, ts_world2cam = [], []
Rs_base2gripper, ts_base2gripper = [], []
for _ in range(n_poses):
R_b2g, t_b2g = self._random_rt()
B = self._to_T(R_b2g, t_b2g)
# Consistent synthetic data: A_i @ X == Z @ B_i => A_i = Z @ B_i @ inv(X)
A = Z @ B @ np.linalg.inv(X)
Rs_world2cam.append(A[:3, :3])
# NOTE: unlike calibrateHandEye, calibrateRobotWorldHandEye's Shah/Li
# solvers require translations as explicit (3,1) column vectors, not
# flat (3,) arrays -- passing (3,) raises a gemm shape-assertion error.
ts_world2cam.append(A[:3, 3].reshape(3, 1))
Rs_base2gripper.append(R_b2g)
ts_base2gripper.append(t_b2g.reshape(3, 1))
R_base2world, t_base2world, R_gripper2cam, t_gripper2cam = cv.calibrateRobotWorldHandEye(
Rs_world2cam, ts_world2cam, Rs_base2gripper, ts_base2gripper)
self.assertLess(cv.norm(R_base2world - R_base2world_gt, cv.NORM_L1), 1e-3)
self.assertLess(cv.norm(t_base2world.flatten() - t_base2world_gt, cv.NORM_L1), 1e-3)
self.assertLess(cv.norm(R_gripper2cam - R_gripper2cam_gt, cv.NORM_L1), 1e-3)
self.assertLess(cv.norm(t_gripper2cam.flatten() - t_gripper2cam_gt, cv.NORM_L1), 1e-3)
if __name__ == '__main__':
NewOpenCVTests.bootstrap()