ImportError: OpenCV loader: missing configuration file: ['config-3.8.py', 'config-3.py'].

[Debactor]

Hi! Thanks for the contribution! I am asking for the solution of the following issue!

System Description
Jetson Orin nano Ubuntu 20.04
Jetpack 5.1.4 (CUDA 11.4)
OpenCV 4.5.5 (with CUDA)
opencv_contrib-4.4.5

My Issue Description
I used the source code downloaded from github to install opencv. My Cmake command is as follows:
cmake \ -DCMAKE_BUILD_TYPE=Release \ -DCMAKE_INSTALL_PREFIX=/usr/local \ -DOPENCV_ENABLE_NONFREE=1 \ -DBUILD_opencv_python2=1 \ -DBUILD_opencv_python3=1 \ -DBUILD_EXAMPLES=OFF \ -DWITH_FFMPEG=1 \ -DCUDA_TOOLKIT_ROOT_DIR=/usr/local/cuda \ -DCUDA_ARCH_BIN=8.7 \ -DWITH_CUDA=1 \ -DENABLE_FAST_MATH=1 \ -DCUDA_FAST_MATH=1 \ -DWITH_CUBLAS=1 \ -DWITH_CUDNN=ON \ -DOPENCV_DNN_CUDA=ON \ -DOPENCV_GENERATE_PKGCONFIG=1 \ -DOPENCV_EXTRA_MODULES_PATH=../../opencv-4.5.5/opencv_contrib-4.5.5/modules \ ..
, and I succeed in executing the following command:

make -j6
sudo make install

When I use jtop to see if I installed the opencv successfully, it shows that I did.
OpenCV:4.5.5 with CUDA: Yes

And when I used the python-2.7 and type the command python2 -c "import cv2;print(cv2.__version__);" without conda environment, I did get the output: 4.5.5.

However, when I try to use the python-3.8 and type the command python3 -c "import cv2;print(cv2.__version__);", I got No module named 'cv2'. So I executed the commands

cd opencv-4.5.5/build/python_loader
sudo pip3 install .

Then when I execute python3 -c "import cv2;print(cv2.__version__);", I got the error:
Traceback (most recent call last): File "<stdin>", line 1, in <module> File "/home/robot/prj/opencv-4.5.5/build/python_loader/cv2/__init__.py", line 181, in <module> bootstrap() File "/home/robot/prj/opencv-4.5.5/build/python_loader/cv2/__init__.py", line 112, in bootstrap load_first_config([ File "/home/robot/prj/opencv-4.5.5/build/python_loader/cv2/__init__.py", line 109, in load_first_config raise ImportError('OpenCV loader: missing configuration file: {}. Check OpenCV installation.'.format(fnames)) ImportError: OpenCV loader: missing configuration file: ['config-3.8.py', 'config-3.py']. Check OpenCV installation.
No matter I used python3.8 in the base or miniconda virtual environment, I got the same error above.

[opencv-alalek]

sudo make install
sudo pip3 install .

Where did you get these lines? (that tutorial is wrong and harm your setup)
Never do that, especially with sudo. pip should be used in virtuaenv.

In local build directory use this instead:

./setup_vars.sh python3 -c "import cv2 as cv; print(cv.getBuildInformation());"

and ensure that paths are the same (correct module was loaded).

For additional information compare your logs with CI.