c++ - Simple SIFT Detector ISSUE on OpenCV -


i'm implementing simple example familiar opencv , sift.

1  #include <opencv2/core/core.hpp> 2  #include <opencv2/features2d/features2d.hpp> 3  #include <opencv2/highgui/highgui.hpp> 4 5  using namespace std; 6  7  int main(int argc, char** argv) { 8 9     const cv::mat input = cv::imread("/tmp/image.jpg", 0); //load grayscale 10 11    cv::siftfeaturedetector detector; 12    std::vector<cv::keypoint> keypoints; 13    detector.detect(input, keypoints); 14 15    // add results image , save. 16    cv::mat output; 17    cv::drawkeypoints(input, keypoints, output); 18    cv::imwrite("/tmp/sift_result.jpg", output); 19 20    return 0; 21 22 }

i expecting quite straightforward, it's throwing following errors:

  • undefined reference 'cv::sift::commonparams::commonparams()' @ line 11
  • undefined reference 'cv::featuredetector::detect(cv::mat const&, std::vector<cv::keypoint, std::allocator<cv::keypoint> >&, cv::mat const&) const' @ line 13
  • undefined reference 'cv::drawkeypoints(cv::mat const&, std::vector<cv::keypoint, std::allocator<cv::keypoint> > const&, cv::mat&, cv::scalar_<double> const&, int)' @ line 17

can please tell me what's going wrong? problem in code, or missing headers?

complete build output:

make  building file: ../main.cpp invoking: gcc c++ compiler g++ -i/usr/local/include/opencv -i/usr/include/c++/4.5.2 -o0 -g3 -wall -c -fmessage-length=0 -std=c++0x -mmd -mp -mf"main.d" -mt"main.d" -o "main.o" "../main.cpp" finished building: ../main.cpp  building target: bioinfo invoking: gcc c++ linker g++ -l/usr/local/lib -o "bioinfo"  ./imageprocessingclass.o ./main.o   -lopencv_core -lopencv_highgui ./main.o: in function `main': /.../debug/../main.cpp:38: undefined reference `cv::sift::commonparams::commonparams()' /.../debug/../main.cpp:38: undefined reference `cv::sift::detectorparams::detectorparams()' /.../debug/../main.cpp:38: undefined reference `cv::siftfeaturedetector::siftfeaturedetector(cv::sift::detectorparams const&, cv::sift::commonparams const&)' /.../debug/../main.cpp:40: undefined reference `cv::featuredetector::detect(cv::mat const&, std::vector<cv::keypoint, std::allocator<cv::keypoint> >&, cv::mat const&) const' /.../debug/../main.cpp:44: undefined reference `cv::drawkeypoints(cv::mat const&, std::vector<cv::keypoint, std::allocator<cv::keypoint> > const&, cv::mat&, cv::scalar_<double> const&, int)' ./main.o: in function `~siftfeaturedetector': /usr/local/include/opencv2/features2d/features2d.hpp:1502: undefined reference `vtable cv::siftfeaturedetector' /usr/local/include/opencv2/features2d/features2d.hpp:1502: undefined reference `cv::featuredetector::~featuredetector()' collect2: ld returned 1 exit status make: *** [bioinfo] error 1  build finished

it seems have forgotten link opencv libraries. remember if you're linking against opencv 2.4 there new library "non-free" algorithms named opencv_nonfree need link against sift.


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