compile errors with DNN module (Chapter 12)

[ArifSohaib]

There seems to be a problem either with my compilation or the CMake file but I am getting an error with NMSBoxes and DNN_BACKEND_OPENCV being undefined. I tried with both edited and original code and also recompiled OpenCV 4 with Build_opencv_dnn, BUILD_opencv_dnn_objdetect and OPENCV_DNN_OPENCV flags as well as trying both with and without CUDA flags but the error presists and the chapter 12 code either modified or with this repo doesn't work.

[damiles]

Can you paste the error that appears in the command line?

[ArifSohaib]

The original error was undefined reference to DNN_BACKEND_OPENCV and undefined reference to NMSBoxes

I recompiled again and this is the full error:

[ 25%] Building CXX object CMakeFiles/DeepLearning_ch12_face.dir/resnet_ssd_face.cpp.o
[ 50%] Linking CXX executable DeepLearning_ch12_face
CMakeFiles/DeepLearning_ch12_face.dir/resnet_ssd_face.cpp.o: In function `main':
resnet_ssd_face.cpp:(.text+0x92): undefined reference to `cv::CommandLineParser::CommandLineParser(int, char const* const*, cv::String const&)'
resnet_ssd_face.cpp:(.text+0x118): undefined reference to `cv::CommandLineParser::printMessage() const'
resnet_ssd_face.cpp:(.text+0x21c): undefined reference to `cv::dnn::experimental_dnn_v2::readNetFromCaffe(cv::String const&, cv::String const&)'
resnet_ssd_face.cpp:(.text+0x22b): undefined reference to `cv::dnn::experimental_dnn_v2::Net::empty() const'
resnet_ssd_face.cpp:(.text+0x386): undefined reference to `cv::dnn::experimental_dnn_v2::Net::setPreferableTarget(int)'
resnet_ssd_face.cpp:(.text+0x395): undefined reference to `cv::VideoCapture::VideoCapture()'
resnet_ssd_face.cpp:(.text+0x460): undefined reference to `cv::VideoCapture::VideoCapture(int)'
resnet_ssd_face.cpp:(.text+0x488): undefined reference to `cv::VideoCapture::~VideoCapture()'
resnet_ssd_face.cpp:(.text+0x497): undefined reference to `cv::VideoCapture::isOpened() const'
resnet_ssd_face.cpp:(.text+0x52a): undefined reference to `cv::VideoCapture::open(cv::String const&)'
resnet_ssd_face.cpp:(.text+0x557): undefined reference to `cv::VideoCapture::isOpened() const'
resnet_ssd_face.cpp:(.text+0x605): undefined reference to `cv::VideoCapture::operator>>(cv::Mat&)'
resnet_ssd_face.cpp:(.text+0x638): undefined reference to `cv::waitKey(int)'
resnet_ssd_face.cpp:(.text+0x6ad): undefined reference to `cv::cvtColor(cv::_InputArray const&, cv::_OutputArray const&, int, int)'
resnet_ssd_face.cpp:(.text+0x72b): undefined reference to `cv::dnn::experimental_dnn_v2::blobFromImage(cv::Mat const&, double, cv::Size_<int> const&, cv::Scalar_<double> const&, bool, bool)'
resnet_ssd_face.cpp:(.text+0x75f): undefined reference to `cv::dnn::experimental_dnn_v2::Net::setInput(cv::Mat const&, cv::String const&)'
resnet_ssd_face.cpp:(.text+0x7a2): undefined reference to `cv::dnn::experimental_dnn_v2::Net::forward(cv::String const&)'
resnet_ssd_face.cpp:(.text+0x7c5): undefined reference to `cv::getTickFrequency()'
resnet_ssd_face.cpp:(.text+0x7fa): undefined reference to `cv::dnn::experimental_dnn_v2::Net::getPerfProfile(std::vector<double, std::allocator<double> >&)'
resnet_ssd_face.cpp:(.text+0x9e2): undefined reference to `cv::putText(cv::_InputOutputArray const&, cv::String const&, cv::Point_<int>, int, double, cv::Scalar_<double>, int, int, bool)'
resnet_ssd_face.cpp:(.text+0xc4f): undefined reference to `cv::rectangle(cv::Mat&, cv::Rect_<int>, cv::Scalar_<double> const&, int, int, int)'
resnet_ssd_face.cpp:(.text+0xd7c): undefined reference to `cv::getTextSize(cv::String const&, int, double, int, int*)'
resnet_ssd_face.cpp:(.text+0xe58): undefined reference to `cv::rectangle(cv::Mat&, cv::Rect_<int>, cv::Scalar_<double> const&, int, int, int)'
resnet_ssd_face.cpp:(.text+0xefc): undefined reference to `cv::putText(cv::_InputOutputArray const&, cv::String const&, cv::Point_<int>, int, double, cv::Scalar_<double>, int, int, bool)'
resnet_ssd_face.cpp:(.text+0xf7f): undefined reference to `cv::imshow(cv::String const&, cv::_InputArray const&)'
resnet_ssd_face.cpp:(.text+0xfa7): undefined reference to `cv::waitKey(int)'
resnet_ssd_face.cpp:(.text+0x108f): undefined reference to `cv::VideoCapture::~VideoCapture()'
resnet_ssd_face.cpp:(.text+0x109e): undefined reference to `cv::dnn::experimental_dnn_v2::Net::~Net()'
resnet_ssd_face.cpp:(.text+0x10cb): undefined reference to `cv::CommandLineParser::~CommandLineParser()'
resnet_ssd_face.cpp:(.text+0x11c6): undefined reference to `cv::VideoCapture::~VideoCapture()'
resnet_ssd_face.cpp:(.text+0x13fc): undefined reference to `cv::VideoCapture::~VideoCapture()'
resnet_ssd_face.cpp:(.text+0x1410): undefined reference to `cv::dnn::experimental_dnn_v2::Net::~Net()'
resnet_ssd_face.cpp:(.text+0x144c): undefined reference to `cv::CommandLineParser::~CommandLineParser()'
CMakeFiles/DeepLearning_ch12_face.dir/resnet_ssd_face.cpp.o: In function `cv::String::String(char const*)':
resnet_ssd_face.cpp:(.text._ZN2cv6StringC2EPKc[_ZN2cv6StringC5EPKc]+0x54): undefined reference to `cv::String::allocate(unsigned long)'
CMakeFiles/DeepLearning_ch12_face.dir/resnet_ssd_face.cpp.o: In function `cv::String::~String()':
resnet_ssd_face.cpp:(.text._ZN2cv6StringD2Ev[_ZN2cv6StringD5Ev]+0x14): undefined reference to `cv::String::deallocate()'
CMakeFiles/DeepLearning_ch12_face.dir/resnet_ssd_face.cpp.o: In function `cv::operator+(char const*, cv::String const&)':
resnet_ssd_face.cpp:(.text._ZN2cvplEPKcRKNS_6StringE[_ZN2cvplEPKcRKNS_6StringE]+0x5a): undefined reference to `cv::String::allocate(unsigned long)'
CMakeFiles/DeepLearning_ch12_face.dir/resnet_ssd_face.cpp.o: In function `cv::Mat::Mat(int, int, int, void*, unsigned long)':
resnet_ssd_face.cpp:(.text._ZN2cv3MatC2EiiiPvm[_ZN2cv3MatC5EiiiPvm]+0x130): undefined reference to `cv::error(int, cv::String const&, char const*, char const*, int)'
resnet_ssd_face.cpp:(.text._ZN2cv3MatC2EiiiPvm[_ZN2cv3MatC5EiiiPvm]+0x237): undefined reference to `cv::error(int, cv::String const&, char const*, char const*, int)'
CMakeFiles/DeepLearning_ch12_face.dir/resnet_ssd_face.cpp.o: In function `cv::Mat::~Mat()':
resnet_ssd_face.cpp:(.text._ZN2cv3MatD2Ev[_ZN2cv3MatD5Ev]+0x39): undefined reference to `cv::fastFree(void*)'
CMakeFiles/DeepLearning_ch12_face.dir/resnet_ssd_face.cpp.o: In function `cv::Mat::release()':
resnet_ssd_face.cpp:(.text._ZN2cv3Mat7releaseEv[_ZN2cv3Mat7releaseEv]+0x4b): undefined reference to `cv::Mat::deallocate()'
CMakeFiles/DeepLearning_ch12_face.dir/resnet_ssd_face.cpp.o: In function `cv::String::String(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)':
resnet_ssd_face.cpp:(.text._ZN2cv6StringC2ERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE[_ZN2cv6StringC5ERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE]+0x70): undefined reference to `cv::String::allocate(unsigned long)'
CMakeFiles/DeepLearning_ch12_face.dir/resnet_ssd_face.cpp.o: In function `cv::String cv::CommandLineParser::get<cv::String>(cv::String const&, bool) const':
resnet_ssd_face.cpp:(.text._ZNK2cv17CommandLineParser3getINS_6StringEEET_RKS2_b[_ZNK2cv17CommandLineParser3getINS_6StringEEET_RKS2_b]+0x51): undefined reference to `cv::CommandLineParser::getByName(cv::String const&, bool, int, void*) const'
CMakeFiles/DeepLearning_ch12_face.dir/resnet_ssd_face.cpp.o: In function `bool cv::CommandLineParser::get<bool>(cv::String const&, bool) const':
resnet_ssd_face.cpp:(.text._ZNK2cv17CommandLineParser3getIbEET_RKNS_6StringEb[_ZNK2cv17CommandLineParser3getIbEET_RKNS_6StringEb]+0x44): undefined reference to `cv::CommandLineParser::getByName(cv::String const&, bool, int, void*) const'
CMakeFiles/DeepLearning_ch12_face.dir/resnet_ssd_face.cpp.o: In function `int cv::CommandLineParser::get<int>(cv::String const&, bool) const':
resnet_ssd_face.cpp:(.text._ZNK2cv17CommandLineParser3getIiEET_RKNS_6StringEb[_ZNK2cv17CommandLineParser3getIiEET_RKNS_6StringEb]+0x47): undefined reference to `cv::CommandLineParser::getByName(cv::String const&, bool, int, void*) const'
CMakeFiles/DeepLearning_ch12_face.dir/resnet_ssd_face.cpp.o: In function `float cv::CommandLineParser::get<float>(cv::String const&, bool) const':
resnet_ssd_face.cpp:(.text._ZNK2cv17CommandLineParser3getIfEET_RKNS_6StringEb[_ZNK2cv17CommandLineParser3getIfEET_RKNS_6StringEb]+0x49): undefined reference to `cv::CommandLineParser::getByName(cv::String const&, bool, int, void*) const'
collect2: error: ld returned 1 exit status
CMakeFiles/DeepLearning_ch12_face.dir/build.make:94: recipe for target 'DeepLearning_ch12_face' failed
make[2]: *** [DeepLearning_ch12_face] Error 1
CMakeFiles/Makefile2:67: recipe for target 'CMakeFiles/DeepLearning_ch12_face.dir/all' failed
make[1]: *** [CMakeFiles/DeepLearning_ch12_face.dir/all] Error 2
Makefile:83: recipe for target 'all' failed
make: *** [all] Error 2

[damiles]

This error is that you are not linking to the opencv libraries. Check you install correctly opencv library and the libraries are installed correctly