No cuda support after compiling opencv with cuda

[eli.mit.g]

I ran the script from here successfully:

GitHub - mdegans/nano_build_opencv: Build OpenCV on Nvidia Jetson Nano

but when I run cv2.cuda.getCudaEnabledDeviceCount() I still get “0”
What else do I need to do?

[DaneLLL]

Hi,
Please try this script:
JEP/install_opencv4.6.0_Jetson.sh at master · AastaNV/JEP · GitHub

CUDA_ARCH_BIN of Orin is 8.7. Please build with this configuration.

[eli.mit.g]

Thank you - I used the script it seems to work for python 2.7, but not for python 3.8. When I run the commands:

python
import cv2
cv2.cuda.getCudaEnabledDeviceCount

I get:

1

But when I run:

python3
import cv2
cv2.cuda.getCudaEnabledDeviceCount()

I still get:

0

How can I configure python3 to use cuda?

[DaneLLL]

Hi,
It seems like it does not link to self-built OpenCV. Please check if the version is correct in python 3.8:

>>> cv2.__version__

It should work since the path of python 3.8 is included in the script:

echo 'export PYTHONPATH=/usr/local/lib/python3.8/site-packages/:$PYTHONPATH' >> ~/.bashrc

[eli.mit.g]

Ok, after loging in again all seems to work properly (I did not source the .bashrc after install)
Thank you!

[eli.mit.g]

Hi,
This works for python3.8, but I need this for python3.7…
I have installed the python3.7 interperter, but how do I install the opencv with CUDA for 3.7?

[AastaLLL]

Hi,

You can modify the CMake command to build the OpenCV library for python 3.7.
For example, below are steps for building OpenCV with python 3.9.

** Install NumPy for python 3.9

$ sudo -H python3.9 -m pip install numpy --upgrade numpy

** Update CMake command for python 3.9
https://github.com/AastaNV/JEP/blob/master/script/install_opencv4.6.0_Jetson.sh#L62

$ cmake \
-D PYTHON_LIBRARIES=/usr/lib/python3.9/config-3.9-aarch64-linux-gnu/libpython3.9.so \
-D PYTHON3_EXECUTABLE=/usr/bin/python3.9 \
-D WITH_CUDA=ON -D WITH_CUDNN=ON -D CUDA_ARCH_BIN="7.2,8.7" -D CUDA_ARCH_PTX="" -D OPENCV_GENERATE_PKGCONFIG=ON -D OPENCV_EXTRA_MODULES_PATH=../../opencv_contrib-${version}/modules -D WITH_GSTREAMER=ON -D WITH_LIBV4L=ON -D BUILD_opencv_python3=ON -D BUILD_TESTS=OFF -D BUILD_PERF_TESTS=OFF -D BUILD_EXAMPLES=OFF -D CMAKE_BUILD_TYPE=RELEASE -D CMAKE_INSTALL_PREFIX=/usr/local ..

You should find python 3.9 in the CMake configuration:

-- General configuration for OpenCV 4.6.0 =====================================
...
--   Python 3:
--     Interpreter:                 /usr/bin/python3.9 (ver 3.9.5)
--     Libraries:                   /usr/lib/aarch64-linux-gnu/libpython3.9.so (ver 3.9.5)
--     numpy:                       /usr/local/lib/python3.9/dist-packages/numpy/core/include (ver 1.23.4)
--     install path:                lib/python3.9/site-packages/cv2/python-3.9
-- 
...

Thanks.