Trouble with cross-compiling an c++ openCV application for the beaglebone black

Question

I hoping somebody has a quick solution because I'm getting a tiny, weeny bit frustrated. I'm trying to cross-compile an openCV application for my Beaglebone Black (BBB) on my Linux Ubuntu 14.04 computer. I installed the cross compilers: arm-linux-gnueabihf-gcc-4.8 en arm-linux-gnueabihf-g++-4.8. cross . These work when I compile a simple c++ program without linking to 3th party libs, like openCV.

Because I want to compile for my BBB I mounted (samba) my beaglebone in the folder /mnt/BBB/ on my linux computer. And I tried the following code (which is a copy of http://docs.opencv.org/doc/tutorials/introduction/linux_gcc_cmake/linux_gcc_cmake.html )

#include <stdio.h>
#include <opencv2/opencv.hpp>

using namespace cv;

int main(int argc, char** argv )
{
    if ( argc != 2 )
    {
        printf("usage: DisplayImage.out <Image_Path>\n");
        return -1;
    }

    Mat image;
    image = imread( argv[1], 1 );

    if ( !image.data )
    {
        printf("No image data \n");
        return -1;
    }
    namedWindow("Display Image", 1 );
    imshow("Display Image", image);

    waitKey(0);

    return 0;
}

With the following command:

arm-g++ -I/mnt/BBB/usr/local/include -I/mnt/BBB/usr/local/include/opencv -L/mnt/BBB/usr/local/lib  -lopencv_calib3d -lopencv_core -lopencv_features2d -lopencv_flann -lopencv_highgui -lopencv_imgcodecs -lopencv_imgproc -lopencv_ml -lopencv_objdetect -lopencv_photo -lopencv_shape -lopencv_stitching     -lopencv_superres -lopencv_ts -lopencv_video -lopencv_videoio -lopencv_videostab main.cpp -o main

But I receive the following error:

/tmp/ccX4FOL8.o: In function `main':
main.cpp:(.text+0x4c): undefined reference to `cv::imread(cv::String const&, int)'
main.cpp:(.text+0xa6): undefined reference to `cv::namedWindow(cv::String const&, int)'
main.cpp:(.text+0xe2): undefined reference to `cv::imshow(cv::String const&, cv::_InputArray const&)'
main.cpp:(.text+0xfc): undefined reference to `cv::waitKey(int)'
/tmp/ccX4FOL8.o: In function `cv::String::String(char const*)':
main.cpp:(.text._ZN2cv6StringC2EPKc[_ZN2cv6StringC5EPKc]+0x2a): undefined reference to `cv::String::allocate(unsigned int)'
/tmp/ccX4FOL8.o: In function `cv::String::~String()':
main.cpp:(.text._ZN2cv6StringD2Ev[_ZN2cv6StringD5Ev]+0xa): undefined reference to `cv::String::deallocate()'
/tmp/ccX4FOL8.o: In function `cv::_InputArray::_InputArray(cv::Mat const&)':
main.cpp:(.text._ZN2cv11_InputArrayC2ERKNS_3MatE[_ZN2cv11_InputArrayC5ERKNS_3MatE]+0x34): undefined reference to `vtable for cv::_InputArray'
/tmp/ccX4FOL8.o: In function `cv::_InputArray::~_InputArray()':
main.cpp:(.text._ZN2cv11_InputArrayD2Ev[_ZN2cv11_InputArrayD5Ev]+0x24): undefined reference to `vtable for cv::_InputArray'
/tmp/ccX4FOL8.o: In function `cv::Mat::~Mat()':
main.cpp:(.text._ZN2cv3MatD2Ev[_ZN2cv3MatD5Ev]+0x20): undefined reference to `cv::fastFree(void*)'
/tmp/ccX4FOL8.o: In function `cv::Mat::operator=(cv::Mat const&)':
main.cpp:(.text._ZN2cv3MataSERKS0_[_ZN2cv3MataSERKS0_]+0xb4): undefined reference to `cv::Mat::copySize(cv::Mat const&)'
/tmp/ccX4FOL8.o: In function `cv::Mat::release()':
main.cpp:(.text._ZN2cv3Mat7releaseEv[_ZN2cv3Mat7releaseEv]+0x3e): undefined reference to `cv::Mat::deallocate()'
collect2: error: ld returned 1 exit status

Can somebody tell me what I'm doing wrong? Or what could be done better?

Thank you

Answer 1

It looks like you are not linking the library properly! Why aren't you using CMake?

 target_link_libraries(your_project ${OpenCV_LIBS})

Here you find the full reference on Cross compiling: http://www.vtk.org/Wiki/CMake_Cross_Compiling

Anyway, I've found this on OpenCV forum group:

Cross compile OpenCV but failed to find 3rd party library