Calling third-party Python modules installed with homebrew from Matlab?

I've installed the OpenCV library for Python using homebrew. I've successfully used it within Python for weeks, but now I'd like to attempt calling OpenCV functions from Matlab. Currently I'm able to call built-in libraries without issue, but not third-party modules. How can I get this working? Thanks!

[the cyclist]

Leaving this comment only so I can easily find this question again. Several months ago, I did some of this exploration, and I think I ended up achieving only what you have.

Answer 1

[Robert Snoeberger]

Use the import_module function from importlib when you want more information about an import failure. If import fails, then you will get the Python exception. The exception will give you more information about the cause of the failure.

I can reproduce the import failure:

>> py.importlib.import_module('cv2')
Python Error: dlopen(/usr/local/Cellar/opencv3/3.0.0/lib/python2.7/site-packages/cv2.so, 2): Library not loaded:
/usr/local/lib/libtiff.5.dylib
  Referenced from: /usr/local/Cellar/opencv3/3.0.0/lib/libopencv_imgcodecs.3.0.dylib
  Reason: Incompatible library version: libopencv_imgcodecs.3.0.dylib requires version 8.0.0 or later, but libtiff.5.dylib provides
  version 6.0.0

>>

As you can see in the error message, the cause of the failure is an incompatible library version. The library that is causing the problem is libtiff.5.dylib. I have two versions of the library, 1) a version located at /usr/local/lib/libtiff.5.dylib that Python normally uses and 2) another version located at /Applications/MATLAB_R2014b.app/bin/maci64/libtiff.5.dylib that MATLAB uses. When you call opencv functions from MATLAB, the MATLAB version of the library is picked up and it is incompatible.

Related questions have been asked on MATLAB Answers. See here and here .

[Dylan Brown]

>> py.importlib.import_module('cv2')
Python Error: dlopen(/usr/local/lib/python2.7/site-packages/cv2.so, 2): Symbol not found:
__ZN2cv14chamerMatchingERNS_3MatES1_RNSt3__16vectorINS3_INS_6Point_IiEENS2_9allocatorIS5_EEEENS6_IS8_EEEERNS3_IfNS6_IfEEEEdidiiidddd
  Referenced from: /usr/local/lib/python2.7/site-packages/cv2.so
  Expected in: /Applications/MATLAB_R2014b.app/bin/maci64/libopencv_contrib.2.4.dylib
 in /usr/local/lib/python2.7/site-packages/cv2.so

Thanks! This is the exception output I get. Is there any linker setting I can change to get around the problem?