Boost Python wrapper for a c++ class that uses Opencv 2.3

I am trying to create a python library from a class which uses opencv 2.3. I want to be able to pass numpy array's into the class where they will be converted into cv::Mat's processed then converted back to numpy array's and returned.

Here is a simple开发者_如何学编程 test class I am working on to get this working before wrapping my own class. Currently I am just trying to receive a numpy array concert to a cv::Mat, process it and then write it to file. After this is working I will work on returning the processed array to python.

Here is the simple class:

foo.h :

#include <opencv2/core/core.hpp>

 class Foo {
    public:
        Foo();
        ~Foo();

        cv::Mat image;

        void bar( cv::Mat in );
}; 

foo.cpp :

  #include "foo.h"

  Foo::Foo(){}

  Foo::~Foo(){}

  void Foo::bar( cv::Mat in) {
      image = in;
      cv::Canny( image, image, 50, 100 );
      cv::imwrite("image.png", image);
  }

And here is where I have attempted to wrap this class using boost::python (I am using code from the opencv source for the the numpy to mat conversion)

wrap_foo.cpp

#include <boost/python.hpp>
#include <numpy/arrayobject.h>

#include <opencv2/core/core.hpp>

#include "foo.h"

using namespace cv;
namespace bp = boost::python;

//// Wrapper Functions
void bar(Foo& f, bp::object np);

//// Converter Functions
cv::Mat convertNumpy2Mat(bp::object np);

//// Wrapper Functions
void bar(Foo& f, bp::object np)
{
    Mat img = convertNumpy2Mat(np);
    f.bar(img);
    return; 
}


//// Boost Python Class
BOOST_PYTHON_MODULE(lib)
{   
    bp::class_<Foo>("Foo")
        .def("bar", bar)
        ;
}


//// Converters
cv::Mat convertNumpy2Mat(bp::object np)
{
   Mat m;
   numpy_to_mat(np.ptr(),m);
   return m;
}

The numpy_to_mat function is from the opencv source (modules/python/src2/cv2.cpp). The full file has the function below what I wrote above. This code compiles with bjam just fine but the when I import into python it crashes. The error is this: libFoo.so: undefined symbol: _ZN2cv3Mat10deallocateEv. I have tried a number of different things but I can't get this to work.

Help is most appreciated.

---

I think this is probably a bit late but it may be useful to others who experienced the same problem...

I think you need to add the path to the newly created library to your LD_LIBRARY_PATH for your program to locate it.

Assuming the current directory '.' is where your library is at, type the following in your terminal before running your program:

export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:.

NOTE: The above is temporary export is temporary. You might want to copy your libs to standard library paths such as /usr/local/lib or add the path permanently by including the above command in your .profile (or any shell startup configuration file).