CPP中的OpenCV库（具体来说，文件letter_recog.cpp）

Question

我只是试图从opencv库中为cpp编译/构建/运行示例代码，当我尝试构建时，我遇到了问题。

我按照http://docs.opencv.org/2.4/doc/tutorials/introduction/linux_gcc_cmake/linux_gcc_cmake.html正确安装了opencv 以及将框架文件中的opencv包含文件移动到/ usr / local / include / opencv2的include中 将opencv包含文件从框架移动到该文件夹​​有助于解决我的大部分问题（找不到opencv2文件），但是构建文件 letter_recog.cpp 的问题无效。如果不工作，我的意思是它有很多构建错误。

该文件的代码如下： https://github.com/opencv/opencv/blob/master/samples/cpp/letter_recog.cpp

构建错误如下：

g++ -g -std=c++14 -Wall -Wextra -pedantic -lpthread  -o "letter_recog"  "letter_recog.cpp" (in directory: /home/courtneymaroney/opencv/samples/cpp)
/tmp/ccUbgW02.o: In function `read_num_class_data(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, int, cv::Mat*, cv::Mat*)':
/home/courtneymaroney/opencv/samples/cpp/letter_recog.cpp:74: undefined reference to `cv::Mat::push_back(cv::Mat const&)'
/home/courtneymaroney/opencv/samples/cpp/letter_recog.cpp:77: undefined reference to `cv::Mat::copyTo(cv::_OutputArray const&) const'
/tmp/ccUbgW02.o: In function `prepare_train_data(cv::Mat const&, cv::Mat const&, int)':
/home/courtneymaroney/opencv/samples/cpp/letter_recog.cpp:100: undefined reference to `cv::Mat::zeros(int, int, int)'
/tmp/ccUbgW02.o: In function `prepare_train_data(cv::Mat const&, cv::Mat const&, int)':
/usr/local/include/opencv2/core/mat.hpp:1110: undefined reference to `cv::noArray()'
/tmp/ccUbgW02.o: In function `prepare_train_data(cv::Mat const&, cv::Mat const&, int)':
/home/courtneymaroney/opencv/samples/cpp/letter_recog.cpp:102: undefined reference to `cv::Mat::setTo(cv::_InputArray const&, cv::_InputArray const&)'
/tmp/ccUbgW02.o: In function `prepare_train_data(cv::Mat const&, cv::Mat const&, int)':
/usr/local/include/opencv2/core/mat.hpp:1110: undefined reference to `cv::noArray()'
/tmp/ccUbgW02.o: In function `prepare_train_data(cv::Mat const&, cv::Mat const&, int)':
/home/courtneymaroney/opencv/samples/cpp/letter_recog.cpp:106: undefined reference to `cv::Mat::setTo(cv::_InputArray const&, cv::_InputArray const&)'
/home/courtneymaroney/opencv/samples/cpp/letter_recog.cpp:110: undefined reference to `cv::noArray()'
/home/courtneymaroney/opencv/samples/cpp/letter_recog.cpp:110: undefined reference to `cv::noArray()'
/home/courtneymaroney/opencv/samples/cpp/letter_recog.cpp:110: undefined reference to `cv::ml::TrainData::create(cv::_InputArray const&, int, cv::_InputArray const&, cv::_InputArray const&, cv::_InputArray const&, cv::_InputArray const&, cv::_InputArray const&)'
/tmp/ccUbgW02.o: In function `test_and_save_classifier(cv::Ptr<cv::ml::StatModel> const&, cv::Mat const&, cv::Mat const&, int, int, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)':
/usr/local/include/opencv2/ml.hpp:349: undefined reference to `cv::noArray()'
/tmp/ccUbgW02.o: In function `build_rtrees_classifier(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)':
/home/courtneymaroney/opencv/samples/cpp/letter_recog.cpp:187: undefined reference to `cv::ml::RTrees::create()'
/home/courtneymaroney/opencv/samples/cpp/letter_recog.cpp:208: undefined reference to `cv::sum(cv::_InputArray const&)'
/tmp/ccUbgW02.o: In function `build_boost_classifier(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)':
/usr/local/include/opencv2/core/mat.hpp:1110: undefined reference to `cv::noArray()'
/tmp/ccUbgW02.o: In function `build_boost_classifier(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)':
/home/courtneymaroney/opencv/samples/cpp/letter_recog.cpp:277: undefined reference to `cv::Mat::setTo(cv::_InputArray const&, cv::_InputArray const&)'
/home/courtneymaroney/opencv/samples/cpp/letter_recog.cpp:281: undefined reference to `cv::noArray()'
/home/courtneymaroney/opencv/samples/cpp/letter_recog.cpp:281: undefined reference to `cv::noArray()'
/home/courtneymaroney/opencv/samples/cpp/letter_recog.cpp:281: undefined reference to `cv::noArray()'
/home/courtneymaroney/opencv/samples/cpp/letter_recog.cpp:281: undefined reference to `cv::ml::TrainData::create(cv::_InputArray const&, int, cv::_InputArray const&, cv::_InputArray const&, cv::_InputArray const&, cv::_InputArray const&, cv::_InputArray const&)'
/home/courtneymaroney/opencv/samples/cpp/letter_recog.cpp:287: undefined reference to `cv::ml::Boost::create()'
/home/courtneymaroney/opencv/samples/cpp/letter_recog.cpp:314: undefined reference to `cv::noArray()'
/tmp/ccUbgW02.o: In function `build_mlp_classifier(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)':
/home/courtneymaroney/opencv/samples/cpp/letter_recog.cpp:383: undefined reference to `cv::Mat::zeros(int, int, int)'
/tmp/ccUbgW02.o: In function `build_mlp_classifier(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)':
/usr/local/include/opencv2/ml.hpp:285: undefined reference to `cv::noArray()'
/usr/local/include/opencv2/ml.hpp:285: undefined reference to `cv::noArray()'
/usr/local/include/opencv2/ml.hpp:284: undefined reference to `cv::noArray()'
/usr/local/include/opencv2/ml.hpp:284: undefined reference to `cv::noArray()'
/tmp/ccUbgW02.o: In function `build_mlp_classifier(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)':
/home/courtneymaroney/opencv/samples/cpp/letter_recog.cpp:408: undefined reference to `cv::ml::TrainData::create(cv::_InputArray const&, int, cv::_InputArray const&, cv::_InputArray const&, cv::_InputArray const&, cv::_InputArray const&, cv::_InputArray const&)'
/home/courtneymaroney/opencv/samples/cpp/letter_recog.cpp:411: undefined reference to `cv::ml::ANN_MLP::create()'
/tmp/ccUbgW02.o: In function `build_knearest_classifier(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, int)':
/home/courtneymaroney/opencv/samples/cpp/letter_recog.cpp:440: undefined reference to `cv::ml::KNearest::create()'
/tmp/ccUbgW02.o: In function `build_nbayes_classifier(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)':
/home/courtneymaroney/opencv/samples/cpp/letter_recog.cpp:467: undefined reference to `cv::ml::NormalBayesClassifier::create()'
/tmp/ccUbgW02.o: In function `build_svm_classifier(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)':
/home/courtneymaroney/opencv/samples/cpp/letter_recog.cpp:504: undefined reference to `cv::ml::SVM::create()'
/tmp/ccUbgW02.o: In function `main':
/home/courtneymaroney/opencv/samples/cpp/letter_recog.cpp:524: undefined reference to `cv::CommandLineParser::CommandLineParser(int, char const* const*, cv::String const&)'
/home/courtneymaroney/opencv/samples/cpp/letter_recog.cpp:526: undefined reference to `cv::CommandLineParser::has(cv::String const&) const'
/home/courtneymaroney/opencv/samples/cpp/letter_recog.cpp:528: undefined reference to `cv::CommandLineParser::has(cv::String const&) const'
/home/courtneymaroney/opencv/samples/cpp/letter_recog.cpp:530: undefined reference to `cv::CommandLineParser::has(cv::String const&) const'
/home/courtneymaroney/opencv/samples/cpp/letter_recog.cpp:532: undefined reference to `cv::CommandLineParser::has(cv::String const&) const'
/home/courtneymaroney/opencv/samples/cpp/letter_recog.cpp:534: undefined reference to `cv::CommandLineParser::has(cv::String const&) const'
/tmp/ccUbgW02.o:/home/courtneymaroney/opencv/samples/cpp/letter_recog.cpp:536: more undefined references to `cv::CommandLineParser::has(cv::String const&) const' follow
/tmp/ccUbgW02.o: In function `main':
/home/courtneymaroney/opencv/samples/cpp/letter_recog.cpp:557: undefined reference to `cv::CommandLineParser::~CommandLineParser()'
/home/courtneymaroney/opencv/samples/cpp/letter_recog.cpp:524: undefined reference to `cv::CommandLineParser::~CommandLineParser()'
/tmp/ccUbgW02.o: In function `cv::String::String(char const*)':
/usr/local/include/opencv2/core/cvstd.hpp:618: undefined reference to `cv::String::allocate(unsigned long)'
/tmp/ccUbgW02.o: In function `cv::String::~String()':
/usr/local/include/opencv2/core/cvstd.hpp:660: undefined reference to `cv::String::deallocate()'
/tmp/ccUbgW02.o: In function `cv::Mat::Mat(int, int, int, void*, unsigned long)':
/usr/local/include/opencv2/core/mat.inl.hpp:413: undefined reference to `cv::error(int, cv::String const&, char const*, char const*, int)'
/tmp/ccUbgW02.o: In function `cv::Mat::~Mat()':
/usr/local/include/opencv2/core/mat.inl.hpp:556: undefined reference to `cv::fastFree(void*)'
/tmp/ccUbgW02.o: In function `cv::Mat::row(int) const':
/usr/local/include/opencv2/core/mat.inl.hpp:591: undefined reference to `cv::Mat::Mat(cv::Mat const&, cv::Range const&, cv::Range const&)'
/tmp/ccUbgW02.o: In function `cv::Mat::rowRange(int, int) const':
/usr/local/include/opencv2/core/mat.inl.hpp:603: undefined reference to `cv::Mat::Mat(cv::Mat const&, cv::Range const&, cv::Range const&)'
/tmp/ccUbgW02.o: In function `cv::Mat::colRange(int, int) const':
/usr/local/include/opencv2/core/mat.inl.hpp:615: undefined reference to `cv::Mat::Mat(cv::Mat const&, cv::Range const&, cv::Range const&)'
/tmp/ccUbgW02.o: In function `cv::Mat::create(int, int, int)':
/usr/local/include/opencv2/core/mat.inl.hpp:648: undefined reference to `cv::Mat::create(int, int const*, int)'
/tmp/ccUbgW02.o: In function `cv::Mat::release()':
/usr/local/include/opencv2/core/mat.inl.hpp:667: undefined reference to `cv::Mat::deallocate()'
/tmp/ccUbgW02.o: In function `cv::FileStorage::getFirstTopLevelNode() const':
/usr/local/include/opencv2/core/persistence.hpp:1167: undefined reference to `cv::FileStorage::root(int) const'
/tmp/ccUbgW02.o: In function `cv::FileNode::begin() const':
/usr/local/include/opencv2/core/persistence.hpp:1184: undefined reference to `cv::FileNodeIterator::FileNodeIterator(CvFileStorage const*, CvFileNode const*, unsigned long)'
/tmp/ccUbgW02.o: In function `cv::FileNode::end() const':
/usr/local/include/opencv2/core/persistence.hpp:1185: undefined reference to `cv::FileNode::size() const'
/usr/local/include/opencv2/core/persistence.hpp:1185: undefined reference to `cv::FileNodeIterator::FileNodeIterator(CvFileStorage const*, CvFileNode const*, unsigned long)'
/tmp/ccUbgW02.o: In function `cv::String::String(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)':
/usr/local/include/opencv2/core/cvstd.inl.hpp:81: undefined reference to `cv::String::allocate(unsigned long)'
/tmp/ccUbgW02.o: In function `cv::String cv::CommandLineParser::get<cv::String>(cv::String const&, bool) const':
/usr/local/include/opencv2/core/utility.hpp:682: undefined reference to `cv::CommandLineParser::getByName(cv::String const&, bool, int, void*) const'
/tmp/ccUbgW02.o: In function `cv::Mat::Mat<int>(std::vector<int, std::allocator<int> > const&, bool)':
/usr/local/include/opencv2/core/mat.inl.hpp:469: undefined reference to `cv::Mat::copyTo(cv::_OutputArray const&) const'
/tmp/ccUbgW02.o: In function `cv::Mat::Mat<double>(std::vector<double, std::allocator<double> > const&, bool)':
/usr/local/include/opencv2/core/mat.inl.hpp:469: undefined reference to `cv::Mat::copyTo(cv::_OutputArray const&) const'
/tmp/ccUbgW02.o: In function `cv::Ptr<cv::ml::RTrees> cv::Algorithm::load<cv::ml::RTrees>(cv::String const&, cv::String const&)':
/usr/local/include/opencv2/core.hpp:2972: undefined reference to `cv::FileStorage::FileStorage(cv::String const&, int, cv::String const&)'
/usr/local/include/opencv2/core.hpp:2973: undefined reference to `cv::FileStorage::operator[](cv::String const&) const'
/usr/local/include/opencv2/core.hpp:2974: undefined reference to `cv::ml::RTrees::create()'
/usr/local/include/opencv2/core.hpp:2972: undefined reference to `cv::FileStorage::~FileStorage()'
/usr/local/include/opencv2/core.hpp:2972: undefined reference to `cv::FileStorage::~FileStorage()'
/tmp/ccUbgW02.o: In function `cv::Ptr<cv::ml::Boost> cv::Algorithm::load<cv::ml::Boost>(cv::String const&, cv::String const&)':
/usr/local/include/opencv2/core.hpp:2972: undefined reference to `cv::FileStorage::FileStorage(cv::String const&, int, cv::String const&)'
/usr/local/include/opencv2/core.hpp:2973: undefined reference to `cv::FileStorage::operator[](cv::String const&) const'
/usr/local/include/opencv2/core.hpp:2974: undefined reference to `cv::ml::Boost::create()'
/usr/local/include/opencv2/core.hpp:2972: undefined reference to `cv::FileStorage::~FileStorage()'
/usr/local/include/opencv2/core.hpp:2972: undefined reference to `cv::FileStorage::~FileStorage()'
/tmp/ccUbgW02.o: In function `cv::Ptr<cv::ml::ANN_MLP> cv::Algorithm::load<cv::ml::ANN_MLP>(cv::String const&, cv::String const&)':
/usr/local/include/opencv2/core.hpp:2972: undefined reference to `cv::FileStorage::FileStorage(cv::String const&, int, cv::String const&)'
/usr/local/include/opencv2/core.hpp:2973: undefined reference to `cv::FileStorage::operator[](cv::String const&) const'
/usr/local/include/opencv2/core.hpp:2974: undefined reference to `cv::ml::ANN_MLP::create()'
/usr/local/include/opencv2/core.hpp:2972: undefined reference to `cv::FileStorage::~FileStorage()'
/usr/local/include/opencv2/core.hpp:2972: undefined reference to `cv::FileStorage::~FileStorage()'
/tmp/ccUbgW02.o: In function `cv::Ptr<cv::ml::SVM> cv::Algorithm::load<cv::ml::SVM>(cv::String const&, cv::String const&)':
/usr/local/include/opencv2/core.hpp:2972: undefined reference to `cv::FileStorage::FileStorage(cv::String const&, int, cv::String const&)'
/usr/local/include/opencv2/core.hpp:2973: undefined reference to `cv::FileStorage::operator[](cv::String const&) const'
/usr/local/include/opencv2/core.hpp:2974: undefined reference to `cv::ml::SVM::create()'
/usr/local/include/opencv2/core.hpp:2972: undefined reference to `cv::FileStorage::~FileStorage()'
/usr/local/include/opencv2/core.hpp:2972: undefined reference to `cv::FileStorage::~FileStorage()'
collect2: error: ld returned 1 exit status
Compilation failed.

我正在为Ubuntu 16.04使用名为“Geany”的IDE。

granny的compile / build命令如下： 编译： g ++ -std = c ++ 14 -Wall -c“％f” 建立： g ++ -g -std = c ++ 14 -Wall -Wextra -pedantic -lpthread -o“％e”“％f”

我在互联网上寻找可能的解决方案。似乎有些人有这个问题，但还没有人找到解决方案，或者至少没有人为此分享过。

echo $（pkg-config --libs opencv）的输出[我将其格式化以使其更具可读性]：

echo $(pkg-config --libs opencv)

/usr/lib/x86_64-linux-gnu/libopencv_calib3d.so

 -lopencv_calib3d

/usr/lib/x86_64-linux-gnu/libopencv_contrib.so

 -lopencv_contrib 

/usr/lib/x86_64-linux-gnu/libopencv_core.so 

-lopencv_core

 /usr/lib/x86_64-linux-gnu/libopencv_features2d.so 

-lopencv_features2d 

/usr/lib/x86_64-linux-gnu/libopencv_flann.so

 -lopencv_flann

 /usr/lib/x86_64-linux-gnu/libopencv_gpu.so 

-lopencv_gpu 

/usr/lib/x86_64-linux-gnu/libopencv_highgui.so

 -lopencv_highgui

 /usr/lib/x86_64-linux-gnu/libopencv_imgproc.so 

-lopencv_imgproc 

/usr/lib/x86_64-linux-gnu/libopencv_legacy.so

 -lopencv_legacy 

/usr/lib/x86_64-linux-gnu/libopencv_ml.so

 -lopencv_ml 

/usr/lib/x86_64-linux-gnu/libopencv_objdetect.so

 -lopencv_objdetect 

/usr/lib/x86_64-linux-gnu/libopencv_ocl.so

-lopencv_ocl 

/usr/lib/x86_64-linux-gnu/libopencv_photo.so

 -lopencv_photo 

/usr/lib/x86_64-linux-gnu/libopencv_stitching.so 

-lopencv_stitching 

/usr/lib/x86_64-linux-gnu/libopencv_superres.so 

-lopencv_superres

 /usr/lib/x86_64-linux-gnu/libopencv_ts.so 

-lopencv_ts 

/usr/lib/x86_64-linux-gnu/libopencv_video.so

 -lopencv_video

 /usr/lib/x86_64-linux-gnu/libopencv_videostab.so

 -lopencv_videostab

Answer 1

我不明白你是如何在你的系统上安装opencv的，如果你真的手动复制系统路径中的标题，那么我可能不想知道。此外，我对IDE过敏，所以让我们使用更友好的终端。

通常最好的选择是在存储库中安装一个。在你的情况下（从你的问题的标签看来它是一个ubuntu 16.10）：

sudo apt update
sudo apt install libopencv-dev

这将修复将帮助您编译的pkg-config文件。 （免责声明手动复制的标头可能会影响安装过程。我建议您在发出这两个命令之前删除它们，如果您将它们放入/usr/include）

现在编译letter_recog.cpp就足以以这种方式调用编译器了：

g++ $(pkg-config --cflags --libs opencv) letter_recog.cpp -o letter_recog

如果你想要，你也可以添加你的旗帜（-Wall -pedantic等等），但我建议你检查一下pkg-config做什么：

echo $(pkg-config --cflags opencv)
echo $(pkg-config --libs opencv)

第二个特别是您显然错过了（要链接的库）。

最后，为了修复Geany我怀疑你必须放置类似的地方：

g++ -std=c++14 -Wall $(pkg-config --cflags opencv) -c "%f"

和

g++ -g -std=c++14 -Wall -Wextra -pedantic -lpthread $(pkg-config --libs opencv) -o "%e" "%f"

但是此解决方案值得怀疑（例如-lpthread而不是-pthread;并且您也不需要它们用于该代码。）

长话短说：听听DanMašek的第一条评论：他是对的。

（对不起打印错误，我的导火索已经很晚了）

Answer 2

修正：使用本指南重新安装：

https://medium.com/@debugvn/installing-opencv-3-3-0-on-ubuntu-16-04-lts-7db376f93961

没有使用g++ $(pkg-config --cflags --libs opencv) letter_recog.cpp -o letter_recog，所以我不得不添加一些标志（-lopencv_name_of_library）

我有一个带有makefile的菜鸟。一旦我找到了用Makefile替换变量的文件名的方法，我将在这里给出一个自定义的makefile（作为编辑）来编译/构建项目，但到目前为止，因为我使用的是一个名为 Geany ，我正在使用 build 命令（对于所有项目，并不重要）

g++ $(pkg-config --cflags --libs opencv) %f -o %e -lopencv_stitching -lopencv_superres -lopencv_videostab -lopencv_photo -lopencv_aruco -lopencv_bgsegm -lopencv_bioinspired -lopencv_ccalib -lopencv_dpm -lopencv_face -lopencv_freetype -lopencv_fuzzy -lopencv_img_hash -lopencv_line_descriptor -lopencv_optflow -lopencv_reg -lopencv_rgbd -lopencv_saliency -lopencv_stereo -lopencv_structured_light -lopencv_phase_unwrapping -lopencv_surface_matching -lopencv_tracking -lopencv_datasets -lopencv_text -lopencv_dnn -lopencv_plot -lopencv_ml -lopencv_xfeatures2d -lopencv_shape -lopencv_video -lopencv_ximgproc -lopencv_calib3d -lopencv_features2d -lopencv_highgui -lopencv_videoio -lopencv_flann -lopencv_xobjdetect -lopencv_imgcodecs -lopencv_objdetect -lopencv_xphoto -lopencv_imgproc -lopencv_core

谢谢大家的帮助。最有帮助的评论是建议我安装错误的评论。希望我的发现有助于其他人。 （相信我，这是地狱，在尝试不同的安装指南后，试图安装一个nvidia驱动程序并且它损坏了我的整个操作系统，所以我不得不卸载该操作系统，重新安装操作系统，并重新开始操作（重新开始）（全部丢失）我的文件在过程中））

希望你们不必经历我所遇到的麻烦。这是地狱，但我认为opencv非常值得。