dlib cnn_face_detection_model_v1 Python error

Question

I'm trying to use the dlib (v19.6) Python API to create a CNN face detector using the code:

cnn_face_detector = dlib.cnn_face_detection_model_v1('mmod_human_face_detector.dat')

However, I get an ArgumentError as follows:

---------------------------------------------------------------------------
ArgumentError                             Traceback (most recent call last)
<ipython-input-16-c2ca0a6e8dff> in <module>()
----> 1 cnn_face_detector = dlib.cnn_face_detection_model_v1('mmod_human_face_detector.dat')

ArgumentError: Python argument types in
    cnn_face_detection_model_v1.__init__(cnn_face_detection_model_v1, str)
did not match C++ signature:
    __init__(_object*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >)

What might I be doing wrong? Can I not pass the filename of the model file simply as a string?

Answer 1

This works for me, using this fresh release and your usage is correct!

This probably means, that you either:

• did something wrong during install
  • installed by python setup.py install? That would be correct!
• or: your python-interpreter is using some other dlib-version without your knowledge

Answer 2

I had a simmilar issue after python setup.py install due to python using an older version of dlib from /opt/conda/lib/python3.6/site-packages/dlib.so.

Doing a simple mv /opt/conda/lib/python3.6/site-packages/dlib.so /opt/conda/lib/python3.6/site-packages/dlib_old.so solved it for me.