CalibrateCamera returns bad intrinsic Matrix [closed]
Hey there,
I'm currently working on a cameracalibration using a Chessboard. The cornerdetection works perfectly and everything runs without error, the return value of calibrateCamera() is somewhere ~0.2. From what i understood from the documentation is, that the intrinsic matrix returned by CalibrateCamera should look like this:
[fx,0,cx]
[0,fy,cy]
[0 ,0 ,1]
but what i get in return looks like this:
[~0 ,0, 0]
[~4,0, 0]
[0,~0*,0]
~0 -> not really zero but something with e-10 or more
*-> sometimes not zero but insanly large (e+15)
I'm using 40 samples, with a 10x6 Chessboard. Running on 1280x800 capture resolution. I don' set any Flags for calibrate Camera and thus i don't give it any preset intrinsic values, just an empty shell for the Matrix. The distortion-coeffs are alright.
important parts of the Code:
void camCalib()
{
Mat intrinsic = Mat(3, 3, CV_32FC1);
Mat distCoeffs;
distCoeffs = Mat(1, 5, CV_64F);
vector<Mat> rvecs;
vector<Mat> tvecs;
VideoCapture cap = VideoCapture(0); // activate Camerahandle
cap.set(CV_CAP_PROP_FRAME_HEIGHT, 800);
cap.set(CV_CAP_PROP_FRAME_WIDTH, 1280);
Mat vidImg, vidImgBackup, greyMat, blurredMat, blurredMat2, binaryImg, conturImg, undistortedImg; // Varaibles to save different Imagestages
namedWindow("Video", WINDOW_AUTOSIZE);
namedWindow("FilteredVideo", WINDOW_AUTOSIZE);
int xPoints = 6;
int yPoints = 10;
Size patternsize(yPoints, xPoints);
vector<Point2f> corners;
bool once = true;
Scalar color = Scalar(255, 0, 0); // circle color
vector<vector<Point3f>> CalibPointWorldPositions;
vector<vector<Point2f>> CalibPointImagePositions;
vector<Mat> t_vec_col;
vector<Mat> r_vec_col;
int zPoints = 40;
[...] // fill WorldPosition Vector, all Points on the same z-Level
Size ImageSize;
int counter = 0;
int buttonPressed = waitKey(1);
while (buttonPressed != 27)
{
buttonPressed = waitKey(1);
cap.read(vidImg);
ImageSize = vidImg.size();
cvtColor(vidImg, greyMat, CV_BGR2GRAY);
imshow("Video", vidImg);
if (buttonPressed == 13) // press Enter
{
bool patternfound = findChessboardCorners(vidImg, patternsize, corners,
CALIB_CB_ADAPTIVE_THRESH + CALIB_CB_NORMALIZE_IMAGE
+ CALIB_CB_FAST_CHECK);
TermCriteria criteria = TermCriteria(CV_TERMCRIT_EPS + CV_TERMCRIT_ITER, 100, 0.001);
if (patternfound)
{
cout << "pattern found" << endl;
drawChessboardCorners(vidImg, patternsize, Mat(corners), patternfound);
cornerSubPix(greyMat, corners, Size(5,5), Size(-1,-1), criteria);
CalibPointImagePositions.push_back(corners);
counter++;
}
imshow("Video", vidImg);
if (counter == zPoints)
{
if (once)
{
//once = !once;
cout << "calibrating Camera..." << endl;
TermCriteria criteria = TermCriteria(CV_TERMCRIT_EPS + CV_TERMCRIT_ITER, 10, 0.001);
cout << calibrateCamera(CalibPointWorldPositions, CalibPointImagePositions, ImageSize, intrinsic, distCoeffs, rvecs, tvecs, 0,criteria) << endl;
//print intrinsic matrix:
cout << intrinsic.ptr<float>(0)[0] << " ;; " << intrinsic.ptr<float>(1)[0] << " ;; " << intrinsic.ptr<float>(2)[0] << endl;
cout << intrinsic.ptr<float>(0)[1] << " ;; " << intrinsic.ptr<float>(1)[1] << " ;; " << intrinsic.ptr<float>(2)[1] << endl;
cout << intrinsic.ptr<float>(0)[2] << " ;; " << intrinsic.ptr<float>(1)[2] << " ;; " << intrinsic.ptr<float>(2)[2] << endl;
[...] // rest of the code is not important
}
Thanks in advance Captain_Obvious
can it be, the intrinsics Mat is double, not float ?
you sir, are my hero... i've been searching for this damn problem for days... it really was just a problem of the output...