BackgroundSubtractorMOG2 & OpenCV

I'm trying to compile the simple example at http://mateuszstankiewicz.eu/?p=189 I'm running Ubuntu 12.10 64 bits.I use OpenCV 2.4.4a I compile using a makefile that does this : ``` g++ background_subtraction.cpp -o background_subtraction -I/usr/local/include/opencv -I/usr/local/include/opencv2 -L /usr/local/lib -lm -lopencv_core -lopencv_highgui -lopencv_imgproc -lcvblob ``` The errors : ``` /tmp/cc0ZWnll.o: dans la fonction « main »: background_subtraction.cpp:(.text+0x96): référence indéfinie vers « cv::BackgroundSubtractorMOG2::BackgroundSubtractorMOG2() » background_subtraction.cpp:(.text+0x1f0): référence indéfinie vers « cv::BackgroundSubtractorMOG2::operator()(cv::_InputArray const&, cv::_OutputArray const&, double) » background_subtraction.cpp:(.text+0x222): référence indéfinie vers « cv::BackgroundSubtractorMOG2::getBackgroundImage(cv::_OutputArray const&) const » background_subtraction.cpp:(.text+0x61a): référence indéfinie vers « cv::BackgroundSubtractorMOG2::~BackgroundSubtractorMOG2() » background_subtraction.cpp:(.text+0x7a6): référence indéfinie vers « cv::BackgroundSubtractorMOG2::~BackgroundSubtractorMOG2() » collect2: erreur: ld a retourné 1 code d'état d'exécution ``` Means : undefined reference to ... The background_subtraction.cpp file : ``` #include <opencv2/opencv.hpp> #include <iostream> #include <vector> int main (int argc, char *argv[]) { cv::Mat frame; cv::Mat back; cv::Mat fore; cv::VideoCapture cap (0); cv::BackgroundSubtractorMOG2 bg; bg.set ("nmixtures", 3); //bg.bShadowDetection = false; std::vector < std::vector < cv::Point > >contours; cv::namedWindow ("Frame"); cv::namedWindow ("Background"); for (;;) { cap >> frame; bg.operator()(frame, fore); bg.getBackgroundImage (back); cv::erode (fore, fore, cv::Mat ()); cv::dilate (fore, fore, cv::Mat ()); cv::findContours (fore, contours, CV_RETR_EXTERNAL, CV_CHAIN_APPROX_NONE); cv::drawContours (frame, contours, -1, cv::Scalar (0, 0, 255), 2); cv::imshow ("Frame", frame); cv::imshow ("Background", back); if (cv::waitKey (30) >= 0) break; } return 0; } ``` What am I missing to compile this program succesfully ? Thanks :)