‘calibrateCamera’ is not a member of ‘cv’

edit

hi everyone. i have a problem calling calibrateCamera() in a simple code that i tried.

   vector<vector <Point3f> > objectPoints;
   vector<vector <Point2f> > imagePoints;
   Mat cameraMatrix;
   Size imageSize(320, 240); 
   Mat distCoeffs;
   vector<Mat> rvecs,tvecs;

  double x = cv::calibrateCamera(objectPoints,
                imagePoints,
                imageSize,
                cameraMatrix,
                distCoeffs,
                rvecs,tvecs,
                0);

sadly i'm getting this response from the g++

fsd.cpp: In function ‘int main(int, char**)’: fsd.cpp:60:14: error: ‘calibrateCamera’ is not a member of ‘cv’

the cv:: is not needed because i typed in the head ‘using namespace cv;‘

so i tried to remove the ‘cv::‘ then i got

‘calibrateCamera’ was not declared in this scope

thanks in advance!!!