I have installed opencv2.
pkg-config --modversion opencv
2.4.13.5
I am using below code,
#include <iostream>
#include <opencv2/opencv.hpp>
using namespace std;
using namespace cv;
int main(int argc, const char *argv[])
{
VideoCapture vid(0);
if(!vid.isOpened()){
cout<<"Camera could not load..."<<endl;
return -1;
}
namedWindow("webcam",CV_WINDOW_AUTOSIZE);
while(1){
Mat frame;
bool ctrl = vid.read(frame);
imshow("webcam",frame);
if(waitKey(0) == 27){
cout<<"The app is ended..."<<endl;
break;
}
}
return 0;
}
I compiled using, g++ image_writer.cpp
/tmp/ccPWmgA0.o: In function main':
image_writer.cpp:(.text+0x38): undefined reference tocv::VideoCapture::VideoCapture(int)'
image_writer.cpp:(.text+0x47): undefined reference to cv::VideoCapture::isOpened() const'
image_writer.cpp:(.text+0xac): undefined reference tocv::namedWindow(std::__cxx11::basic_string, std::allocator > const&, int)'
image_writer.cpp:(.text+0xe9): undefined reference to cv::VideoCapture::read(cv::Mat&)'
image_writer.cpp:(.text+0x105): undefined reference tocv::_InputArray::_InputArray(cv::Mat const&)'
image_writer.cpp:(.text+0x148): undefined reference to cv::imshow(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, cv::_InputArray const&)'
image_writer.cpp:(.text+0x170): undefined reference tocv::waitKey(int)'
image_writer.cpp:(.text+0x1cd): undefined reference to cv::VideoCapture::~VideoCapture()'
image_writer.cpp:(.text+0x254): undefined reference tocv::VideoCapture::~VideoCapture()'
/tmp/ccPWmgA0.o: In function cv::Mat::~Mat()':
image_writer.cpp:(.text._ZN2cv3MatD2Ev[_ZN2cv3MatD5Ev]+0x39): undefined reference tocv::fastFree(void*)'
/tmp/ccPWmgA0.o: In function cv::Mat::release()':
image_writer.cpp:(.text._ZN2cv3Mat7releaseEv[_ZN2cv3Mat7releaseEv]+0x47): undefined reference tocv::Mat::deallocate()'
collect2: error: ld returned 1 exit status
After surfing I found, I have to include lib file
so, I did this. g++ image_writer.cpp -lopencv_videoio
/usr/bin/ld: cannot find -lopencv_videoio
collect2: error: ld returned 1 exit status
I don't know how to fix this. please help me how to fix this. Any hint would be appreciable.
EDIT-1:
pkg-config --libs opencv returns,
-L/usr/local/lib -lopencv_contrib -lopencv_stitching -lopencv_nonfree -lopencv_superres -lopencv_ocl -lopencv_ts -lopencv_videostab -lopencv_gpu -lopencv_photo -lopencv_objdetect -lopencv_legacy -lopencv_video -lopencv_ml -lopencv_calib3d -lopencv_features2d -lopencv_highgui -lopencv_imgproc -lopencv_flann -lopencv_core -lQtCore -lQtTest -lQtGui -lQtOpenGL -lIlmThread -lHalf -lIex -lIlmImf -lImath -ljasper -ltiff -lpng -ljpeg -lswscale-ffmpeg -lavutil-ffmpeg -lavformat-ffmpeg -lavcodec-ffmpeg -lv4l2 -lv4l1 -ldc1394 -lgstpbutils-0.10 -lgstriff-0.10 -lgstapp-0.10 -lgstvideo-0.10 -lxml2 -lglib-2.0 -lgthread-2.0 -lgmodule-2.0 -lgobject-2.0 -lgstreamer-0.10 -lgstbase-0.10 -lGLU -lGL -lz -latomic -ltbb -lrt -lpthread -lm -ldl -lstdc++
The OpenCV "library" is really a collection of multiple libraries, and you usually need to link with multiple libraries.
The simple solution is to use pkg-config --libs opencv to get all linker flags and libraries that are needed:
g++ image_writer.cpp `pkg-config --libs opencv`
compilation using cmake
cmake_minimum_required(VERSION 2.8)
project(ImageWriter)
add_executable(${PROJECT_NAME} "image_writer.cpp")
FIND_PACKAGE(OpenCV REQUIRED )
include_directories(${OPENCV_INCLUDE_DIRS})
message(" cv_libs: " ${OpenCV_LIBS})
message(" cv_includes: " ${OPENCV_INCLUDE_DIRS})
TARGET_LINK_LIBRARIES(${PROJECT_NAME} ${OpenCV_LIBS})
Related
I am trying to build a sample from OpenCV. Unfortunately I always get these errors while building.
I made an installation with opencv_contrib. OpenCV is installed in ~/lib/pokus/installed (contains bin include lib share). I am buiding example ~/lib/pokus/installed/share/OpenCV/samples/cpp/opencv_version.cpp (which came with OpenCV).
My g++ command:
g++ $(pkg-config --cflags --libs ~/lib/pokus/installed/lib/pkgconfig/opencv.pc) opencv_version.cpp -o test
Result:
opencv_version.cpp:(.text+0x78): undefined reference to `cv::CommandLineParser::CommandLineParser(int, char const* const*, cv::String const&)'
opencv_version.cpp:(.text+0xa8): undefined reference to `cv::CommandLineParser::has(cv::String const&) const'
opencv_version.cpp:(.text+0xc6): undefined reference to `cv::CommandLineParser::printMessage() const'
opencv_version.cpp:(.text+0xd7): undefined reference to `cv::CommandLineParser::check() const'
opencv_version.cpp:(.text+0xea): undefined reference to `cv::CommandLineParser::printErrors() const'
opencv_version.cpp:(.text+0x113): undefined reference to `cv::CommandLineParser::has(cv::String const&) const'
opencv_version.cpp:(.text+0x12a): undefined reference to `cv::getBuildInformation()'
opencv_version.cpp:(.text+0x180): undefined reference to `cv::CommandLineParser::~CommandLineParser()'
opencv_version.cpp:(.text+0x1bc): undefined reference to `cv::CommandLineParser::~CommandLineParser()'
opencv_version.cpp:(.text+0x1f8): undefined reference to `cv::CommandLineParser::~CommandLineParser()'
/tmp/ccRHDRg5.o: In function `cv::String::String(char const*)':
opencv_version.cpp:(.text._ZN2cv6StringC2EPKc[_ZN2cv6StringC5EPKc]+0x4d): undefined reference to `cv::String::allocate(unsigned long)'
/tmp/ccRHDRg5.o: In function `cv::String::~String()':
opencv_version.cpp:(.text._ZN2cv6StringD2Ev[_ZN2cv6StringD5Ev]+0x14): undefined reference to `cv::String::deallocate()'
collect2: error: ld returned 1 exit status
Content of ~/lib/pokus/installed/lib/pkgconfig/opencv.pc
# Package Information for pkg-config
prefix=~/lib/pokus/installed
exec_prefix=${prefix}
libdir=${exec_prefix}/lib
includedir_old=${prefix}/include/opencv
includedir_new=${prefix}/include
Name: OpenCV
Description: Open Source Computer Vision Library
Version: 3.2.0
Libs: -L${exec_prefix}/lib -lopencv_stitching -lopencv_superres -lopencv_videostab -lopencv_aruco -lopencv_bgsegm -lopencv_bioinspired -lopencv_ccalib -lopencv_cvv -lopencv_dpm -lopencv_freetype -lopencv_fuzzy -lopencv_line_descriptor -lopencv_optflow -lopencv_reg -lopencv_saliency -lopencv_stereo -lopencv_structured_light -lopencv_phase_unwrapping -lopencv_rgbd -lopencv_surface_matching -lopencv_tracking -lopencv_datasets -lopencv_text -lopencv_face -lopencv_plot -lopencv_dnn -lopencv_xfeatures2d -lopencv_shape -lopencv_video -lopencv_ximgproc -lopencv_calib3d -lopencv_features2d -lopencv_flann -lopencv_xobjdetect -lopencv_objdetect -lopencv_ml -lopencv_xphoto -lopencv_highgui -lopencv_videoio -lopencv_imgcodecs -lopencv_photo -lopencv_imgproc -lopencv_core
Libs.private: -L/usr/lib/x86_64-linux-gnu -lQt5Test -lQt5Concurrent -lQt5OpenGL -lpng -lz -ltiff -ljasper -ljpeg -lImath -lIlmImf -lIex -lHalf -lIlmThread -ldc1394 -lavcodec-ffmpeg -lavformat-ffmpeg -lavutil-ffmpeg -lswscale-ffmpeg -lQt5Core -lQt5Gui -lQt5Widgets -ldl -lm -lpthread -lrt -lGLU -lGL -ltbb
Cflags: -I${includedir_old} -I${includedir_new}
Sorry for so frequently asked question, but none of the others seems to solve my problem.
Thanks for all tips!
The file name must come before the params:
g++ opencv_version.cpp $(pkg-config --cflags --libs ~/lib/pokus/installed/lib/pkgconfig/opencv.pc) -o test
I had the same issue trying to work with OPENCV 4.3.0 after installation and so. In order to add the libs and compile properly.
Worked for me in order to test the opencv_version.cpp
g++ opencv_version.cpp $(pkg-config --cflags --libs opencv4) -o opencv_version
Result
./opencv_version
Welcome to OpenCV 4.3.0
I would like to compile a C++ program that uses openCV statically, so that I can use it on other computers without having to install openCV.
I compiled openCV 2.4.5 with following flags in order to get static libraries and to install it besides my main installation which is version 3.1.
cmake -D CMAKE_BUILD_TYPE=RELEASE -D CMAKE_INSTALL_PREFIX=/opt/openCV_2_4_5 -D WITH_FFMPEG=OFF -DBUILD_SHARED_LIBS=NO ..
ls /opt/openCV_2_4_5/lib
libopencv_calib3d.a libopencv_flann.a libopencv_legacy.a libopencv_photo.a libopencv_video.a
libopencv_contrib.a libopencv_gpu.a libopencv_ml.a libopencv_stitching.a libopencv_videostab.a
libopencv_core.a libopencv_highgui.a libopencv_nonfree.a libopencv_superres.a pkgconfig
libopencv_features2d.a libopencv_imgproc.a libopencv_objdetect.a libopencv_ts.a python2.7
After installing, I tried to compile a c++ program for face detection like this:
g++ -std=c++11 -L/opt/openCV_2_4_5/lib -I/opt/openCV_2_4_5/include -o ex2 ex2.cpp -L. -lpthread -lz -lopencv_stitching -lopencv_superres -lopencv_videostab -lopencv_aruco -lopencv_bgsegm -lopencv_bioinspired -lopencv_ccalib -lopencv_dnn -lopencv_dpm -lopencv_fuzzy -lopencv_line_descriptor -lopencv_optflow -lopencv_plot -lopencv_reg -lopencv_saliency -lopencv_stereo -lopencv_structured_light -lopencv_rgbd -lopencv_surface_matching -lopencv_tracking -lopencv_datasets -lopencv_text -lopencv_face -lopencv_xfeatures2d -lopencv_shape -lopencv_video -lopencv_ximgproc -lopencv_calib3d -lopencv_features2d -lopencv_flann -lopencv_xobjdetect -lopencv_objdetect -lopencv_ml -lopencv_xphoto -lopencv_videoio -lopencv_imgcodecs -lopencv_photo -lopencv_imgproc -lopencv_core
From that I got the error:
/tmp/cct4prBn.o: In function `main':
ex2.cpp:(.text+0x141): undefined reference to `cv::imread(std::string const&, int)'
ex2.cpp:(.text+0x2bc): undefined reference to `cv::imread(std::string const&, int)'
ex2.cpp:(.text+0x4f3): undefined reference to `cv::imwrite(std::string const&, cv::_InputArray const&, std::vector<int, std::allocator<int> > const&)'
collect2: error: ld returned 1 exit status
make_2_4_5:9: recipe for target 'ex2' failed
make: *** [ex2] Error 1
I used the same library flags as my installation of OpenCV 3.1 has. I got them from:
pkg-config --cflags --libs opencv
The -L and -I flags point to the openCV 2.4.5 installation in the /opt directory.
Why doesn't it compile? All OpenCV libraries are listed in the section where the static libraries should be.
In OpenCV 2 I believe cv::imread() and cv::imwrite() are in the highgui library. In OpenCV 3 they were moved to the imgcodecs library. Try adding:
-lopencv_highgui
to your command line.
I'm bundling openCV into an SDK for people developing in C++ in linux. I'm linking a test executable with my built library and its giving me a huge dump of errors, one of which is:
/path/to/build/libopencv_core.a(copy.cpp.o): In function `cv::Mat::setTo(cv::_InputArray const&, cv::_InputArray const&)':
copy.cpp:(.text._ZN2cv3Mat5setToERKNS_11_InputArrayES3_+0x15c1): undefined reference to `ippicviSet_32f_C1MR'
copy.cpp:(.text._ZN2cv3Mat5setToERKNS_11_InputArrayES3_+0x1700): undefined reference to `ippicviSet_32f_C4MR'
copy.cpp:(.text._ZN2cv3Mat5setToERKNS_11_InputArrayES3_+0x1743): undefined reference to `ippicviSet_32s_C4MR'
copy.cpp:(.text._ZN2cv3Mat5setToERKNS_11_InputArrayES3_+0x17a4): undefined reference to `ippicviSet_16s_C4MR'
copy.cpp:(.text._ZN2cv3Mat5setToERKNS_11_InputArrayES3_+0x1805): undefined reference to `ippicviSet_16u_C4MR'
What is this error referencing? Should I be building without ipp? I compiled the opencv libs -fPIC and standalone. I'm actually getting thousands of errors which have some mention of ippicvi and this is just an example.
I had the same error. You need to link the executable to the library libippicv.
This is a 3rd party library used by OpenCV an you can find it in /usr/local/share/OpenCV/3rdparty/lib/libippicv.a.
You can also find in opencv.pc all the dependencies used by OpenCV. E.g.:
/usr/local/lib/pkgconfig/opencv.pc
# Package Information for pkg-config
prefix=/usr/local exec_prefix=${prefix} libdir=${exec_prefix}/lib
includedir_old=${prefix}/include/opencv
includedir_new=${prefix}/include
Name: OpenCV
Description: Open Source Computer Vision Library
Version: 3.2.0
Libs: -L${exec_prefix}/lib -lopencv_shape -lopencv_stitching
-lopencv_objdetect -lopencv_superres -lopencv_videostab -lopencv_calib3d -lopencv_features2d -lopencv_highgui -lopencv_videoio -lopencv_imgcodecs -lopencv_video -lopencv_photo -lopencv_ml -lopencv_imgproc -lopencv_flann -lopencv_core
Libs.private: -L${exec_prefix}/share/OpenCV/3rdparty/lib -llibwebp
-lippicv -L/usr/lib/x86_64-linux-gnu -lpng -lz -ltiff -ljasper -ljpeg -lImath -lIlmImf -lIex -lHalf -lIlmThread -lgtk-x11-2.0 -lgdk-x11-2.0 -lpangocairo-1.0 -latk-1.0 -lcairo -lgdk_pixbuf-2.0 -lgio-2.0 -lpangoft2-1.0 -lpango-1.0 -lgobject-2.0 -lglib-2.0 -lfontconfig -lfreetype -lgthread-2.0 -ldc1394 -lavcodec-ffmpeg -lavformat-ffmpeg -lavutil-ffmpeg -lswscale-ffmpeg -lstdc++ -ldl -lm -lpthread -lrt Cflags: -I${includedir_old} -I${includedir_new}
I am getting the following errors:
//usr/local/lib/libsmfitting.so: undefined reference to `VO_FaceParts::VO_GetOneFacePart(unsigned int) const'
//usr/local/lib/libsmfitting.so: undefined reference to `cv::estimateRigidTransform(cv::_InputArray const&, cv::_InputArray const&, bool)'
collect2: error: ld returned 1 exit status
Being produced from this makefile:
Cxx=g++
CXXFLAGS = -I/usr/local/include/opencv -I/usr/local/include/opencv2 -I/usr/local/include/vosm/smfitting -I/usr/local/include/vosm/smbuilding -I/usr/local/include/vosm/comalgs -I/usr/local/include/vosm/cvcommon -I/usr/local/include/vosm/ensembletraining -I/usr/local/include/vosm/featureextraction -I/usr/local/include/vosm/integraltransform -I/usr/local/include/vosm/utils
LIBS = -lopencv_ml -lopencv_calib3d -lopencv_legacy -lopencv_core -lopencv_highgui -lopencv_imgproc -lopencv_video -lopencv_objdetect -lcomalgs -lcvcommon -lensembletraining -lfeatureextraction -lintegraltransform -lsmbuilding -lutils -lboost_system -lboost_filesystem -lsmfitting
all: faceApp.cpp
$(Cxx) -o faceApp faceApp.cpp $(CXXFLAGS) $(LIBS)
The code appears to be correct and the libraries appear to be built correctly, I believe the error lies in the makefile.
The order of the libraries when linking is significant, and should be in reverse dependency order. So if library B depends on library A, then you need to put B before A when linking.
In your case it seems that the smfitting library depends on one of the OpenCV libraries, as well as some other library, so you need to put it before those libraries.
libcv-dev install
10.04
Any ideas as to where the following might be defined?
ahcarpenter#ahcarpenter-laptop:~$ g++ objectmarker.o -o objectmarker
objectmarker.o: In function `on_mouse(int, int, int, int, void*)':
objectmarker.cpp:(.text+0x12f): undefined reference to `cvCloneImage'
objectmarker.cpp:(.text+0x1d1): undefined reference to `cvRectangle'
objectmarker.cpp:(.text+0x1ea): undefined reference to `cvShowImage'
objectmarker.cpp:(.text+0x1f4): undefined reference to `cvReleaseImage'
objectmarker.o: In function `main':
objectmarker.cpp:(.text+0x391): undefined reference to `cvNamedWindow'
objectmarker.cpp:(.text+0x3aa): undefined reference to `cvSetMouseCallback'
objectmarker.cpp:(.text+0x4da): undefined reference to `cvLoadImage'
objectmarker.cpp:(.text+0x50f): undefined reference to `cvShowImage'
objectmarker.cpp:(.text+0x519): undefined reference to `cvWaitKey'
objectmarker.cpp:(.text+0x53f): undefined reference to `cvReleaseImage'
objectmarker.cpp:(.text+0x54e): undefined reference to `cvDestroyWindow'
objectmarker.cpp:(.text+0xd7f): undefined reference to `cvReleaseImage'
objectmarker.cpp:(.text+0xdf3): undefined reference to `cvDestroyWindow'
collect2: ld returned 1 exit status
I tried this and it worked for me:
sudo g++ -I/usr/include/opencv main.cpp -o main -lopencv_core -lopencv_imgproc
-lopencv_highgui -lopencv_ml -lopencv_video -lopencv_features2d -lopencv_calib3d
-lopencv_objdetect -lopencv_contrib -lopencv_legacy -lopencv_flann -I /lib/
-I /home/ubuntu/micros/opencv_directory/include/opencv
I got it from: https://askubuntu.com/questions/239891/opencv-program-wont-compile-quantal
It seems you're not linking against the OpenCV libraries; according to this guide, one way to compile an OpenCV program (after OpenCV has been properly configured) is
g++ `pkg-config opencv --cflags` my_code.cpp -o my_code `pkg-config opencv --libs`
If your C++ code is compiled in a separate step, you can probably drop the --cflags part.
You need to include libraries using pkg-config and cflags.
$ g++ -ggdb `pkg-config --cflags opencv` -o `basename filename.cpp .cpp` filename.cpp `pkg-config --libs opencv
see this link for more details http://www.jayrambhia.com/blog/2012/05/08/beginning-opencv/