OpenCV StereoSGBM gives a very bad mismatch map

Question

this is my calibration code:

void calibrate() { int numBoards = 10; int board_w = 6; int board_h = 9; Size board_sz = Size(board_w, board_h); int board_n = board_w*board_h; vector<vector<Point3f> > object_points; vector<vector<Point2f> > imagePoints1, imagePoints2; vector<Point2f> corners1, corners2; vector<Point3f> obj; for (int j=0; j<board_n; j++) { obj.push_back(Point3f(j/board_w, j%board_w, 0.0f)); } Mat img1, img2, gray1, gray2; VideoCapture cap1(0); VideoCapture cap2(1); int success = 0, k = 0; bool found1 = false, found2 = false; namedWindow("left 1"); namedWindow("right 1"); while (success < numBoards) { cap1 >> img1; cap2 >> img2; cvtColor(img1, gray1, CV_BGR2GRAY); cvtColor(img2, gray2, CV_BGR2GRAY); found1 = findChessboardCorners(img1, board_sz, corners1, CV_CALIB_CB_ADAPTIVE_THRESH | CV_CALIB_CB_FILTER_QUADS); found2 = findChessboardCorners(img2, board_sz, corners2, CV_CALIB_CB_ADAPTIVE_THRESH | CV_CALIB_CB_FILTER_QUADS); if (found1) { cornerSubPix(gray1, corners1, Size(11, 11), Size(-1, -1), TermCriteria(CV_TERMCRIT_EPS | CV_TERMCRIT_ITER, 30, 0.1)); drawChessboardCorners(gray1, board_sz, corners1, found1); } if (found2) { cornerSubPix(gray2, corners2, Size(11, 11), Size(-1, -1), TermCriteria(CV_TERMCRIT_EPS | CV_TERMCRIT_ITER, 30, 0.1)); drawChessboardCorners(gray2, board_sz, corners2, found2); } imshow("left 1", img1); imshow("right 1", img2); k = cv::waitKey(2); if(found1) cout<<"found 1"<<endl; if(found2) cout<<"found 2"<<endl; if(!found1 && !found2) cout<<"no"<<endl; if ( found1 && found2) { imagePoints1.push_back(corners1); imagePoints2.push_back(corners2); object_points.push_back(obj); printf ("Corners stored\n"); success++; if (success >= numBoards) { break; } } } destroyAllWindows(); printf("Starting Calibration\n"); Mat CM1 = Mat(3, 3, CV_64FC1); Mat CM2 = Mat(3, 3, CV_64FC1); Mat D1, D2; Mat R, T, E, F; stereoCalibrate(object_points, imagePoints1, imagePoints2, CM1, D1, CM2, D2, img1.size(), R, T, E, F, cvTermCriteria(CV_TERMCRIT_ITER+CV_TERMCRIT_EPS, 100, 1e-5), CV_CALIB_SAME_FOCAL_LENGTH | CV_CALIB_ZERO_TANGENT_DIST); FileStorage fs1("mystereocalib.yml", FileStorage::WRITE); fs1 << "CM1" << CM1; fs1 << "CM2" << CM2; fs1 << "D1" << D1; fs1 << "D2" << D2; fs1 << "R" << R; fs1 << "T" << T; fs1 << "E" << E; fs1 << "F" << F; printf("Done Calibration\n"); printf("Starting Rectification\n"); Mat R1, R2, P1, P2, Q; stereoRectify(CM1, D1, CM2, D2, img1.size(), R, T, R1, R2, P1, P2, Q); fs1 << "R1" << R1; fs1 << "R2" << R2; fs1 << "P1" << P1; fs1 << "P2" << P2; fs1 << "Q" << Q; printf("Done Rectification\n"); printf("Applying Undistort\n"); Mat map1x, map1y, map2x, map2y; Mat imgU1, imgU2; initUndistortRectifyMap(CM1, D1, R1, P1, img1.size(), CV_32FC1, map1x, map1y); initUndistortRectifyMap(CM2, D2, R2, P2, img2.size(), CV_32FC1, map2x, map2y); printf("Undistort complete\n"); cap1.release(); cap2.release(); return; } 

And this is my mismatch card code with different parameters:

  int main(int argc, char* argv[]) { //calibrate(); Mat img1, img2; VideoCapture cap1 = VideoCapture(0); VideoCapture cap2 = VideoCapture(1); cap1 >> img1; cap2 >> img2; Mat Q; FileStorage fs("mystereocalib.yml", FileStorage::READ); fs["Q"] >> Q; Mat CM1, CM2, D1, D2, P1, P2, R1, R2; fs["CM1"] >> CM1; fs["CM2"] >> CM2; fs["D1"] >> D1; fs["D2"] >> D2; fs["P1"] >> P1; fs["P2"] >> P2; fs["R1"] >> R1; fs["R2"] >> R2; fs.release(); Mat map1x, map1y, map2x, map2y; Mat imgU1, imgU2; initUndistortRectifyMap(CM1, D1, R1, P1, img1.size(), CV_32FC1, map1x, map1y); initUndistortRectifyMap(CM2, D2, R2, P2, img2.size(), CV_32FC1, map2x, map2y); while(1) { cap1 >> img1; cap2 >> img2; imshow("img1", img1); imshow("img2", img2); cv::waitKey(1); remap(img1, imgU1, map1x, map1y, INTER_LINEAR, BORDER_CONSTANT, Scalar()); remap(img2, imgU2, map2x, map2y, INTER_LINEAR, BORDER_CONSTANT, Scalar()); Mat g1,g2, disp, disp8; cvtColor(imgU1, g1, CV_BGR2GRAY); cvtColor(imgU2, g2, CV_BGR2GRAY); /*StereoSGBM sbm; sbm.SADWindowSize = 5; sbm.numberOfDisparities = 144; sbm.preFilterCap = 63; sbm.minDisparity = -39; sbm.uniquenessRatio = 10; sbm.speckleWindowSize = 100; sbm.speckleRange = 32; sbm.disp12MaxDiff = 2; sbm.fullDP = true; sbm.P1 = 216; sbm.P2 = 864; sbm(g1, g2, disp);*/ int sadSize = 3; StereoSGBM sbm; sbm.SADWindowSize = sadSize; sbm.numberOfDisparities = 128;//144; sbm.preFilterCap = 63; sbm.minDisparity = 0; //-39; sbm.uniquenessRatio = 10; sbm.speckleWindowSize = 100; sbm.speckleRange = 32; sbm.disp12MaxDiff = 1; sbm.fullDP = true; sbm.P1 = sadSize*sadSize*4; sbm.P2 = sadSize*sadSize*32; sbm(g1, g2, disp); //StereoSGBM sgbm; //sgbm.SADWindowSize = 5; //sgbm.numberOfDisparities = 192; //sgbm.preFilterCap = 4; //sgbm.minDisparity = -64; //sgbm.uniquenessRatio = 1; //sgbm.speckleWindowSize = 150; //sgbm.speckleRange = 2; //sgbm.disp12MaxDiff = 10; //sgbm.fullDP = false; //sgbm.P1 = 600; //sgbm.P2 = 2400; //sgbm(g1, g2, disp); //StereoBM sbm; //sbm.state->SADWindowSize = 9; //sbm.state->numberOfDisparities = 112; //sbm.state->preFilterSize = 5; //sbm.state->preFilterCap = 61; //sbm.state->minDisparity = -39; //sbm.state->textureThreshold = 507; //sbm.state->uniquenessRatio = 0; //sbm.state->speckleWindowSize = 0; //sbm.state->speckleRange = 8; //sbm.state->disp12MaxDiff = 1; //sbm(g1, g2, disp); normalize(disp, disp8, 0, 255, CV_MINMAX, CV_8U); //disp.convertTo(disp8, CV_8U); imshow("disp8", disp8); } waitKey(0); return 0; } 

I'm new to OpenCV and image processing, what am I doing wrong?

Answer 1

Try using this calibration file - https://github.com/foxymop/3DPoseEstimation/blob/master/src/out_camera_data.yml I also tried to calibrate my camera, but getting a little error is very difficult and using these configurations gave me better results than try to find the parameters of my camera (most likely, my camera is similar to the one in the calibration file). In the end, you may not try to use the calibration file at all.