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solvePNP() - Assertion failed

asked 2012-10-09 09:55:40 -0500

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Hello!

I am trying to get the pose of the camera with the help of solvePNP().

After running my program I get the following errors:

OpenCV Error: Assertion failed (0 <= i && i < (int)vv.size()) in getMat, file /opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_graphics_opencv/opencv/work/OpenCV-2.4.2/modules/core/src/matrix.cpp, line 971
libc++abi.dylib: terminate called throwing an exception

I tried to search how to solve these errors, but I couldn't resolve it unfortunately!

Here is my code, all comment/help is much appreciated:

enum Pattern { NOT_EXISTING, CHESSBOARD, CIRCLES_GRID, ASYMMETRIC_CIRCLES_GRID };

void calcBoardCornerPositions(Size boardSize, float squareSize, vector<Point3f>& corners,
                          Pattern patternType)
{
    corners.clear();

switch(patternType)
{
case CHESSBOARD:
case CIRCLES_GRID:
    for( int i = 0; i < boardSize.height; ++i )
        for( int j = 0; j < boardSize.width; ++j )
            corners.push_back(Point3f(float( j*squareSize ), float( i*squareSize ), 0));
    break;

case ASYMMETRIC_CIRCLES_GRID:
    for( int i = 0; i < boardSize.height; i++ )
        for( int j = 0; j < boardSize.width; j++ )
            corners.push_back(Point3f(float((2*j + i % 2)*squareSize), float(i*squareSize), 0));
    break;
}

}

int main(int argc, char* argv[])
{
    float squareSize = 50.f;

Pattern calibrationPattern = CHESSBOARD;

vector<Point2f> boardCorners;
vector<vector<Point2f> > imagePoints;
vector<vector<Point3f> > boardPoints(1);

Size boardSize;
boardSize.width = 9;
boardSize.height = 6;

vector<Mat> intrinsics, distortion;
string filename = "out_camera_xml.xml";
FileStorage fs(filename, FileStorage::READ);
fs["camera_matrix"] >> intrinsics;
fs["distortion_coefficients"] >> distortion;
fs.release();

vector<Mat> rvec, tvec;
Mat img = imread(argv[1], CV_LOAD_IMAGE_GRAYSCALE); // at kell adnom egy kepet

bool found = findChessboardCorners(img, boardSize, boardCorners, CV_CALIB_CB_ADAPTIVE_THRESH);

calcBoardCornerPositions(boardSize, squareSize, boardPoints[0], calibrationPattern);
boardPoints.resize(imagePoints.size(),boardPoints[0]);

solvePnP(boardPoints, boardCorners, intrinsics, distortion, rvec, tvec);

for(int i=0; i<rvec.size(); i++) {
        cout << rvec[i] << endl;
}

return 0;

}

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Comments

I faced with 'assertion failed' problem in another place of this function (OpenCV 2.4.3) According to the documentation objectPoints have to be 3xN/Nx3 1-channel or 1xN/Nx1 3-channel (the same for imagePoints). In my case it works only for default method flag=CV_ITERATIVE. In case of CV_P3P or CV_EPNP 3-channel arrays must be. Otherwise Assertion failed (CV_IS_MAT(_src) && CV_IS_MAT(_dst) && (_src->rows == 1 || _src->cols == 1) && (_dst->rows == 1 || _dst->cols == 1) && _src->cols + _src->rows - 1 == _dst->rows + _dst->cols - 1 && (CV_MAT_TYPE(_src->type) == CV_32FC2 || CV_MAT_TYPE(_src->type) == CV_64FC2) ... in cvUndistortPoints, file OpenCV-2.4.3/modules/imgproc/src/undistort.cpp, line 279

ag gravatar imageag ( 2013-01-22 01:35:31 -0500 )edit

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answered 2014-02-25 04:04:30 -0500

somedev gravatar image

updated 2014-02-25 04:06:53 -0500

the solvePnP() method takes the following as input :

vector<point3f> ObjectPoints, vector<point2f> imagePoints, Mat cameraMatrix, Mat distortionCoeffs, Mat rvec, Mat tvec

The parameters you seem to be passing are:

vector<vector<point3f> > boardPoints, vector<point2f> boardCorners, vector<mat> intrinsics, vector<mat> distortion, vector<mat> rvec, vector<mat> tvec

solvePnP() doesn't implicitly convert vector<vector<t> > to vector<t> like the calibrateCamera() method does, try to pass the parameters iteratively, it will work. Someone should include this in the documentation to avoid confusion.

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Comments

That‘s right!Thank you!

Cpt gravatar imageCpt ( 2014-03-11 07:33:18 -0500 )edit
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Asked: 2012-10-09 09:55:40 -0500

Seen: 3,565 times

Last updated: Feb 25 '14