Unable to Use OpenCV* ‘Face’ Module When Using OpenCV* Provided with OpenVINO™ Installer Package

• Ran face recognition program using cv2.face.LBPHFaceRecognizer_create()in OpenVINO™ environment.
• Received error: AttributeError: module 'cv2' has no attribute 'face'
• Installed OpenCV* from PyPI: pip install opencv-contrib-python
• Ran face recognition program successfully using OpenCV* from PyPI but encountered another error when using OpenCV* DNN module:

  cv2.error: OpenCV(4.6.0) /io/opencv/modules/dnn/src/net_openvino.cpp:511: error: (-2:Unspecified error) Build OpenCV with Inference Engine to enable loading models from Model Optimizer. in function 'readFromModelOptimizer'

OpenCV* provided with OpenVINO™ installer package does not include build with extra modules from opencv_contrib GitHub repository. While OpenCV* from PyPI does not include build with OpenVINO™ support.

Build custom OpenCV* which includes OpenVINO™ Inference Engine and extra modules from opencv_contrib GitHub repository with minimal set of compilation flags:

1. (Recommend) Uninstall pre-built OpenCV*.

   pip uninstall opencv opencv-contrib-python

2. Download OpenCV* from opencv/opencv repository.

   git clone --recurse-submodules  https://github.com/opencv/opencv.git

3. Download OpenCV’s extra modules from opencv/opencv_contrib repository.

   git clone --recurse-submodules  https://github.com/opencv/opencv_contrib.git

4. Create build directory and navigate to the build directory.

   cd opencv

   mkdir build && cd build

5. (Optional) Install some additional dependencies for OpenCV*.

   sudo apt install libcanberra-gtk-module libtbb-dev

6. Download and install OpenVINO™.

   https://www.intel.com/content/www/us/en/developer/tools/openvino-toolkit/download.html

7. Setup environment variables to detect Inference Engine.

   source <installed_openvino>/setupvars.sh

8. Compile and install OpenCV*.

   cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/usr/local -DOPENCV_EXTRA_MODULES_PATH=<downloaded_dir>/opencv_contrib/modules -DWITH_OPENVINO=ON -DPYTHON3_PACKAGES_PATH=/usr/lib/python3/dist-packages ..

   make -j5

   sudo make install

9. Open new Terminal and import OpenCV* with Python*.