如何从openCV与triangulatePoints（）获得良好的坐标

Question

So I have one point, x:1168px, y:1140px on left image and x:1062px, y:1167px on the right image. The real coordinates I got with my program are: 120.91, 4.94059, -175.609 (x, y and z in mm). X and Y seems correct but not Z, the point is something like 1 meter away from my cameras.

Right now I have this code:

FileStorage fsI("intrinsics.yml", FileStorage::READ);
Mat matI1, matI2, matD1, matD2;
fsI["M1"] >> matI1;
fsI["M2"] >> matI2;
fsI["D1"] >> matD1;
fsI["D2"] >> matD2;

CvMat camInt1 = matI1, camInt2 = matI2, camDist1 = matD1, camDist2 = matD2;

FileStorage fs("extrinsics.yml", FileStorage::READ);
Mat mat1, mat2;
fs["P1"] >> mat1;
fs["P2"] >> mat2;

CvMat projMat1 = mat1, projMat2 = mat2;

double pointImg1_a[2] = { 1168, 1140};
Mat pointImg1 = Mat(2,1, CV_64FC1, pointImg1_a);
CvMat _pointImg1 = cvMat(1,1,CV_64FC2,pointImg1_a);
double pointImg2_a[2] = { 1062, 1167};
Mat pointImg2 = Mat(2,1, CV_64FC1, pointImg2_a);
CvMat _pointImg2 = cvMat(1,1,CV_64FC2,pointImg1_a);

cvUndistortPoints(&_pointImg1,&_pointImg1,&camInt1,&camDist1);
cvUndistortPoints(&_pointImg2,&_pointImg2,&camInt2,&camDist2);

Mat point4D = Mat(4,1, CV_64FC1);
cv::triangulatePoints(mat1, mat2, pointImg1, pointImg2, point4D);   

double w = point4D.at<double>(3,0);
double x = point4D.at<double>(0,0)/w;
double y = point4D.at<double>(1,0)/w;
double z = point4D.at<double>(2,0)/w;

cout << x << ", " << y << ", " << z << endl;

return 0;

I tried without using cvUndistortPoints() and with other coordinates, the result are sometimes correct but not always. I really don't know from where could come the error. (Also I'm new with openCV) Thanks for the help.

Answer 1

Dont't you have a mistake at line: "CvMat _pointImg2 = cvMat(1,1,CV_64FC2,pointImg1_a);"

Correct should be: "CvMat _pointImg2 = cvMat(1,1,CV_64FC2, pointImg2_a );"