[C++-sig] Boost Python wrapper for a c++ class that uses Opencv 2.3

[Jim Bosch]

On 09/21/2011 09:31 AM, Kevin Hughes wrote:
> 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 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.
>

Without digging too deeply or getting into possibly better solutions, 
try adding:

import_array();

inside your BOOST_PYTHON_MODULE block.  Or maybe there's some opencv 
initialization function you need to call that will do that for you.  The 
NumPy C-API (which I assume the numpy_to_mat function uses internally) 
needs to be initialized when your module is imported, or you'll get 
segfaults.  The above call to import_array() is how you'd do it if you 
were using the NumPy C-API headers directly.  In any case, you need to 
make sure it gets called somehow.

HTH

Jim Bosch