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2019-08-09 17:57:10 -0600	received badge	● Self-Learner (source)
2019-08-09 12:42:12 -0600	marked best answer	calibrateHandEye precision Hi there! I am using the calibrateHandEye functions from the Calib3d library to get the handEye calibration of a UR10 robot with a camera RealSense fixed to the end effector. After some problems I think, that I got to get the function work properly. But now I am seeing two things that do not fit completely, and I was hoping for a third opinion from your point of view. As you can see from the image below, I made 4 four measurements for each of the 5 methods that the function proposes. For each of the methods I used 10, 15, 18 and 20 robot poses with their respective pictures. From here I got a little confused: The first method (CALIB_HAND_EYE_TSAI) give completely different values depending on the amount of robot poses used. At the same time, and with the same values, the others 4 methods seem to converge to certain values close enough between them. Why is that? Though the values of the last 4 methods seem to converge, between them there are important differences. Why is that? Thank you for the help! The camera intrinsic parameters are: std::vector<double> distortionCoefficients(5); // camera distortion distortionCoefficients[0] = 9.6349551984637724e-02; distortionCoefficients[1] = -3.3260675111130217e-01; distortionCoefficients[2] = 0; distortionCoefficients[3] = 0; distortionCoefficients[4] = 2.5833277679122602e-01; double f_x = 1.2993539019658076e+03; // Focal length in x axis double f_y = 1.2993539019658076e+03; // Focal length in y axis (usually the same?) double c_x = 960; // Camera primary point x double c_y = 540; // Camera primary point y cv::Mat cameraMatrix(3, 3, CV_32FC1); cameraMatrix.at<float>(0, 0) = f_x; cameraMatrix.at<float>(0, 1) = 0.0; cameraMatrix.at<float>(0, 2) = c_x; cameraMatrix.at<float>(1, 0) = 0.0; cameraMatrix.at<float>(1, 1) = f_y; cameraMatrix.at<float>(1, 2) = c_y; cameraMatrix.at<float>(2, 0) = 0.0; cameraMatrix.at<float>(2, 1) = 0.0; cameraMatrix.at<float>(2, 2) = 1.0; Link to get the images and poses.
2019-08-09 12:42:12 -0600	received badge	● Scholar (source)
2019-08-09 12:42:11 -0600	edited answer	calibrateHandEye precision The problem was with the calibration of the camera itself. I was assuming, in the OpenCV calibration, that the aspect r
2019-08-09 12:41:04 -0600	answered a question	calibrateHandEye precision The problem was with the calibration of the camera itself. I was assuming, in the OpenCV calibration, that the aspect r
2019-08-07 19:29:07 -0600	received badge	● Student (source)
2019-08-07 13:59:49 -0600	commented question	calibrateHandEye precision I am using a force sensor, there is no problem to hit the object. I am more concerned about the precision in the x, y co
2019-08-07 13:34:35 -0600	marked best answer	Wrong result in calibrateHandEye function [answered] I am working in a robot application, in which I have a camera fixed to a robot gripper. In order to calculate the matrix transformation between the camera and the gripper Hcg I am using the calibrateHandEye new function provided in the OpenCV version 4.1. In the next picture, you can see the description of the function from the OpenCV documentation To use this function I am editing the camera_calibration example of samples\cpp\tutorial_code\calib3d\ I had taken 10 pictures of the chessboard from the camera mounted in the gripper and at the same time I recorded the robot position. I changed the code, now It looks like: // My_handeye.cpp : This file contains the 'main' function. Program execution begins and ends there. // #include <iostream> #include <sstream> #include <string> #include <ctime> #include <cstdio> #include "pch.h" #include <opencv2/opencv.hpp> #include <opencv2/core.hpp> #include <opencv2/core/utility.hpp> #include <opencv2/imgproc.hpp> #include <opencv2/calib3d.hpp> #include <opencv2/imgcodecs.hpp> #include <opencv2/videoio.hpp> #include <opencv2/highgui.hpp> using namespace cv; using namespace std; Mat eulerAnglesToRotationMatrix(Vec3f &theta); Vec3f rotationMatrixToEulerAngles(Mat &R); float rad2deg(float radian); float deg2rad(float degree); int main() { // Camera calibration information std::vector<double> distortionCoefficients(5); // camera distortion distortionCoefficients[0] = 2.4472856611074989e-01; distortionCoefficients[1] = -8.1042032574246325e-01; distortionCoefficients[2] = 0; distortionCoefficients[3] = 0; distortionCoefficients[4] = 7.8769462320821060e-01; double f_x = 1.3624172121852105e+03; // Focal length in x axis double f_y = 1.3624172121852105e+03; // Focal length in y axis (usually the same?) double c_x = 960; // Camera primary point x double c_y = 540; // Camera primary point y cv::Mat cameraMatrix(3, 3, CV_32FC1); cameraMatrix.at<float>(0, 0) = f_x; cameraMatrix.at<float>(0, 1) = 0.0; cameraMatrix.at<float>(0, 2) = c_x; cameraMatrix.at<float>(1, 0) = 0.0; cameraMatrix.at<float>(1, 1) = f_y; cameraMatrix.at<float>(1, 2) = c_y; cameraMatrix.at<float>(2, 0) = 0.0; cameraMatrix.at<float>(2, 1) = 0.0; cameraMatrix.at<float>(2, 2) = 1.0; Mat rvec(3, 1, CV_32F), tvec(3, 1, CV_32F); // std::vector<Mat> R_gripper2base; std::vector<Mat> t_gripper2base; std::vector<Mat> R_target2cam; std::vector<Mat> t_target2cam; Mat R_cam2gripper = (Mat_<float>(3, 3)); Mat t_cam2gripper = (Mat_<float>(3, 1)); vector<String> fn; glob("images/.bmp", fn, false); vector<Mat> images; size_t num_images = fn.size(); //number of bmp files in images folder Size patternsize(6, 8); //number of centers vector<Point2f> centers; //this will be filled by the detected centers float cell_size = 30; vector<Point3f> obj_points; R_gripper2base.reserve(num_images); t_gripper2base.reserve(num_images); R_target2cam.reserve(num_images); t_target2cam.reserve(num_images); for (int i = 0; i < patternsize.height; ++i) for (int j = 0; j < patternsize.width; ++j) obj_points.push_back(Point3f(float(jcell_size), float(i*cell_size), 0.f)); for (size_t i = 0; i < num_images; i++) images.push_back(imread(fn[i])); Mat frame; for (size_t i = 0; i < num_images; i++) { frame = imread(fn[i]); //source image bool patternfound = findChessboardCorners(frame, patternsize, centers); if (patternfound) { drawChessboardCorners(frame, patternsize, Mat(centers), patternfound); //imshow("window", frame); //int key = cv::waitKey(0) & 0xff; solvePnP(Mat(obj_points), Mat(centers), cameraMatrix, distortionCoefficients, rvec, tvec); Mat R; Rodrigues(rvec, R); // R is 3x3 R_target2cam.push_back ... (more)
2019-08-07 12:37:28 -0600	commented question	calibrateHandEye precision What's the difference in the chessboard you are suggesting? I don't see any difference, besides the size of the squares
2019-08-07 12:36:20 -0600	commented question	calibrateHandEye precision What's the difference in the chessboard you are suggesting? I don't see any difference, besides the size of the squares
2019-08-07 12:36:06 -0600	commented question	calibrateHandEye precision What's the difference in the chessboard you are suggesting? I don't see any difference, besides the size of the squares
2019-08-07 12:25:33 -0600	commented question	calibrateHandEye precision Thank you so much for the feedback, Eduardo. Also for me, the results of the Tsai method were weird. It seems like a bug
2019-08-07 11:23:24 -0600	commented question	calibrateHandEye precision Sure, it's done! I got the calibration with the same images of the link above.
2019-08-07 11:22:40 -0600	commented question	calibrateHandEye precision Sure, it's done!
2019-08-07 11:22:37 -0600	edited question	calibrateHandEye precision calibrateHandEye precision Hi there! I am using the calibrateHandEye functions from the Calib3d library to get the hand
2019-08-07 08:15:52 -0600	edited question	calibrateHandEye precision calibrateHandEye precision Hi there! I am using the calibrateHandEye functions from the Calib3d library to get the hand
2019-08-07 08:15:32 -0600	commented question	calibrateHandEye precision Hi Eduardo! Good to see you again helping with this. I added to the original question a link to download the images and
2019-08-07 08:15:01 -0600	commented question	calibrateHandEye precision Hi Eduardo! Good to see you again helping with this. I added to the original question a link to download the images and
2019-08-07 08:08:05 -0600	edited question	calibrateHandEye precision calibrateHandEye precision Hi there! I am using the calibrateHandEye functions from the Calib3d library to get the hand
2019-08-06 16:57:57 -0600	commented question	calibrateHandEye precision In the picture assume the ',' are '.' That´s the Spanish way, sorry for that. Is in mm and degrees
2019-08-06 16:57:16 -0600	commented question	calibrateHandEye precision In the picture assume the ',' are '.' That´s the Spanish way, sorry for that.
2019-08-06 16:08:12 -0600	answered a question	Wrong result in calibrateHandEye function [answered] I actually managed to solve this problem. The general idea was correct, but: I was not understanding correctly the vec
2019-08-06 16:07:31 -0600	asked a question	calibrateHandEye precision calibrateHandEye precision Hi there! I am using the calibrateHandEye functions from the Calib3d library to get the hand
2019-08-01 10:34:01 -0600	received badge	● Enthusiast
2019-07-12 09:17:27 -0600	commented question	Wrong result in calibrateHandEye function [answered] No, the input values are different. MVTec uses a different calibration board, so the images are different and the poses
2019-07-12 09:15:38 -0600	commented question	Wrong result in calibrateHandEye function [answered] No, the input values are different. MVTec uses a different calibration board, so the images are different and the poses
2019-07-12 09:08:31 -0600	commented question	Wrong result in calibrateHandEye function [answered] I rechecked the information of the robot, it seems that the rotation matrix is calculated in the way ZYX: The RPY vecto
2019-07-12 08:57:50 -0600	commented question	Wrong result in calibrateHandEye function [answered] I rechecked the information of the robot, it seems that the rotation matrix is calculated in the way ZYX: The RPY vecto
2019-07-12 08:41:14 -0600	commented question	Wrong result in calibrateHandEye function [answered] Yeah, I checked the frames many times now the best I could...
2019-07-12 08:39:38 -0600	commented question	Wrong result in calibrateHandEye function [answered] Hi Eduardo. Thanks for the interest. The other software is Halcon from MVTec. I got a trial license but is almost finis
2019-07-12 08:32:38 -0600	edited question	Wrong result in calibrateHandEye function [answered] Wrong result in calibrateHandEye function I am working in a robot application, in which I have a camera fixed to a robot
2019-07-12 08:29:15 -0600	edited question	Wrong result in calibrateHandEye function [answered] Wrong result in calibrateHandEye function I am working in a robot application, in which I have a camera fixed to a robot
2019-07-12 08:03:51 -0600	edited question	Wrong result in calibrateHandEye function [answered] Wrong result in calibrateHandEye function I am working in a robot application, in which I have a camera fixed to a robot
2019-07-12 08:02:38 -0600	commented question	Wrong result in calibrateHandEye function [answered] The robot doesn´t give the quaternion or rotation matrix. I can only extract the information about the orientation as RP
2019-07-12 08:02:20 -0600	commented question	Wrong result in calibrateHandEye function [answered] The robot doesn´t give the quaternion or rotation matrix. I can only extract the information about the orientation as RP
2019-07-12 08:01:28 -0600	commented question	Wrong result in calibrateHandEye function [answered] The robot doesn´t give the quaternion or rotation matrix. I can only extract the information about the orientation as RP
2019-07-11 15:11:32 -0600	received badge	● Editor (source)
2019-07-11 15:11:32 -0600	edited question	Wrong result in calibrateHandEye function [answered] Wrong result in calibrateHandEye function I am working in a robot application, in which I have a camera fixed to a robot
2019-07-10 14:34:03 -0600	asked a question	Wrong result in calibrateHandEye function [answered] Wrong result in calibrateHandEye function I am working in a robot application, in which I have a camera fixed to a robot