Installed OpenCV 4.8.0 for Python3.8, still get no module error

[oguzizmirli]

Hi, I set up a python 3.8 virtual environment to install OpenCV 4.8.0 with CUDA support into it. I followed these commands:

$ wget https://github.com/Qengineering/Install-OpenCV-Jetson-Nano/raw/main/OpenCV-4-8-0.sh
$ sudo chmod 755 ./OpenCV-4-8-0.sh
$ ./OpenCV-4-8-0.sh
$ rm OpenCV-4-8-0.sh

Installation was successful. However, when I check import cv2 in python3.8, I get “ModuleNotFoundError: No module named ‘cv2’.” How can I solve this?

I ran opencv_version --verbose here is what I get:

General configuration for OpenCV 4.8.0-dev =====================================
Version control: e95c005

Extra modules:
Location (extra): /home/yasar/opencv_contrib/modules
Version control (extra): d51add3

Platform:
Timestamp: 2023-11-05T12:46:05Z
Host: Linux 4.9.337-tegra aarch64
CMake: 3.10.2
CMake generator: Unix Makefiles
CMake build tool: /usr/bin/make
Configuration: RELEASE

CPU/HW features:
Baseline: NEON FP16
required: NEON
Dispatched code generation: NEON_DOTPROD NEON_FP16
requested: NEON_FP16 NEON_BF16 NEON_DOTPROD
NEON_DOTPROD (1 files): + NEON_DOTPROD
NEON_FP16 (0 files): + NEON_FP16

C/C++:
Built as dynamic libs?: YES
C++ standard: 11
C++ Compiler: /usr/bin/c++ (ver 7.5.0)
C++ flags (Release): -fsigned-char -ffast-math -fno-finite-math-only -W -Wall -Wreturn-type -Wnon-virtual-dtor -Waddress -Wsequence-point -Wformat -Wformat-security -Wmissing-declarations -Wundef -Winit-self -Wpointer-arith -Wshadow -Wsign-promo -Wuninitialized -Wsuggest-override -Wno-delete-non-virtual-dtor -Wno-comment -Wimplicit-fallthrough=3 -Wno-strict-overflow -fdiagnostics-show-option -pthread -fomit-frame-pointer -ffunction-sections -fdata-sections -fvisibility=hidden -fvisibility-inlines-hidden -fopenmp -O3 -DNDEBUG -DNDEBUG
C++ flags (Debug): -fsigned-char -ffast-math -fno-finite-math-only -W -Wall -Wreturn-type -Wnon-virtual-dtor -Waddress -Wsequence-point -Wformat -Wformat-security -Wmissing-declarations -Wundef -Winit-self -Wpointer-arith -Wshadow -Wsign-promo -Wuninitialized -Wsuggest-override -Wno-delete-non-virtual-dtor -Wno-comment -Wimplicit-fallthrough=3 -Wno-strict-overflow -fdiagnostics-show-option -pthread -fomit-frame-pointer -ffunction-sections -fdata-sections -fvisibility=hidden -fvisibility-inlines-hidden -fopenmp -g -O0 -DDEBUG -D_DEBUG
C Compiler: /usr/bin/cc
C flags (Release): -fsigned-char -ffast-math -fno-finite-math-only -W -Wall -Wreturn-type -Waddress -Wsequence-point -Wformat -Wformat-security -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wundef -Winit-self -Wpointer-arith -Wshadow -Wuninitialized -Wno-comment -Wimplicit-fallthrough=3 -Wno-strict-overflow -fdiagnostics-show-option -pthread -fomit-frame-pointer -ffunction-sections -fdata-sections -fvisibility=hidden -fopenmp -O3 -DNDEBUG -DNDEBUG
C flags (Debug): -fsigned-char -ffast-math -fno-finite-math-only -W -Wall -Wreturn-type -Waddress -Wsequence-point -Wformat -Wformat-security -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wundef -Winit-self -Wpointer-arith -Wshadow -Wuninitialized -Wno-comment -Wimplicit-fallthrough=3 -Wno-strict-overflow -fdiagnostics-show-option -pthread -fomit-frame-pointer -ffunction-sections -fdata-sections -fvisibility=hidden -fopenmp -g -O0 -DDEBUG -D_DEBUG
Linker flags (Release): -Wl,–gc-sections -Wl,–as-needed -Wl,–no-undefined
Linker flags (Debug): -Wl,–gc-sections -Wl,–as-needed -Wl,–no-undefined
ccache: NO
Precompiled headers: NO
Extra dependencies: m pthread cudart_static dl rt nppc nppial nppicc nppicom nppidei nppif nppig nppim nppist nppisu nppitc npps cublas cudnn cufft -L/usr/local/cuda-10.2/lib64 -L/usr/lib/aarch64-linux-gnu
3rdparty dependencies:

OpenCV modules:
To be built: alphamat aruco bgsegm bioinspired calib3d ccalib core cudaarithm cudabgsegm cudacodec cudafeatures2d cudafilters cudaimgproc cudalegacy cudaobjdetect cudaoptflow cudastereo cudawarping cudev datasets dnn dnn_objdetect dnn_superres dpm face features2d flann freetype fuzzy gapi hdf hfs highgui img_hash imgcodecs imgproc intensity_transform line_descriptor mcc ml objdetect optflow phase_unwrapping photo plot python2 quality rapid reg rgbd saliency sfm shape stereo stitching structured_light superres surface_matching text tracking ts video videoio videostab wechat_qrcode xfeatures2d ximgproc xobjdetect xphoto
Disabled: world
Disabled by dependency: -
Unavailable: cvv java julia matlab ovis python3 viz
Applications: perf_tests apps
Documentation: NO
Non-free algorithms: YES

GUI: GTK3
GTK+: YES (ver 3.22.30)
GThread : YES (ver 2.56.4)
GtkGlExt: NO
VTK support: NO

Media I/O:
ZLib: /usr/lib/aarch64-linux-gnu/libz.so (ver 1.2.11)
JPEG: /usr/lib/aarch64-linux-gnu/libjpeg.so (ver 80)
WEBP: build (ver encoder: 0x020f)
PNG: /usr/lib/aarch64-linux-gnu/libpng.so (ver 1.6.34)
TIFF: build (ver 42 - 4.2.0)
JPEG 2000: build (ver 2.5.0)
OpenEXR: build (ver 2.3.0)
HDR: YES
SUNRASTER: YES
PXM: YES
PFM: YES

Video I/O:
DC1394: YES (2.2.5)
FFMPEG: YES
avcodec: YES (57.107.100)
avformat: YES (57.83.100)
avutil: YES (55.78.100)
swscale: YES (4.8.100)
avresample: YES (3.7.0)
GStreamer: YES (1.14.5)
v4l/v4l2: YES (linux/videodev2.h)

Parallel framework: TBB (ver 2020.2 interface 11102)

Trace: YES (with Intel ITT)

Other third-party libraries:
Lapack: YES (/usr/lib/aarch64-linux-gnu/liblapack.so /usr/lib/aarch64-linux-gnu/libcblas.so /usr/lib/aarch64-linux-gnu/libatlas.so)
Eigen: YES (ver 3.3.4)
Custom HAL: YES (carotene (ver 0.0.1))
Protobuf: build (3.19.1)
Flatbuffers: builtin/3rdparty (23.5.9)

NVIDIA CUDA: YES (ver 10.2, CUFFT CUBLAS FAST_MATH)
NVIDIA GPU arch: 53
NVIDIA PTX archs:

cuDNN: YES (ver 8.2.1)

Python 2:
Interpreter: /usr/bin/python2.7 (ver 2.7.17)
Libraries: /usr/lib/aarch64-linux-gnu/libpython2.7.so (ver 2.7.17)
numpy: /usr/lib/python2.7/dist-packages/numpy/core/include (ver 1.13.3)
install path: lib/python2.7/dist-packages/cv2/python-2.7

Python (for build): /usr/bin/python2.7

Java:
ant: NO
Java: NO
JNI: NO
Java wrappers: NO
Java tests: NO

Install to: /usr

Thank you.

EDIT: I checked the python version (2.7.17) and it has opencv 4.8.0-dev installed. Do I need to install opencv again and if so, how to do it correctly?

[AastaLLL]

Hi,

Please add -D BUILD_opencv_python3=ON in your script to enable python3 support.
Thanks.

[oguzizmirli]

Hi,
I got this error

CMake Error: The source directory “/home/yasar/opencv/build/BUILD_opencv_python3=ON” does not exist.

there is nothing in /home/yasar/opencv/build/

[AastaLLL]

Hi,

How do you apply the flag?
Please modify the “cmake” line in the script and run it again.

cmake -D BUILD_opencv_python3=ON \
-D CMAKE_BUILD_TYPE=RELEASE \
-D CMAKE_INSTALL_PREFIX=/usr \
...

Thanks.

[oguzizmirli]

Thank you for your reply.
The code is working now but still can’t install it to python3.8. I think the problem is with my install path or folders. This is what I saw during the installation:

Python 2:
– Interpreter: /usr/bin/python2.7 (ver 2.7.17)
– Libraries: /usr/lib/aarch64-linux-gnu/libpython2.7.so (ver 2.7.17)
– numpy: /usr/lib/python2.7/dist-packages/numpy/core/include (ver 1.13.3)
– install path: lib/python2.7/dist-packages/cv2/python-2.7

– Python 3:
– Interpreter: /home/yasar/pythonUAV/py38/bin/python3 (ver 3.8)
– Libraries: NO
– numpy: /home/yasar/pythonUAV/py38/lib/python3.8/site-packages/numpy/core/include (ver 1.24.4)
– install path: -

– Python (for build): /usr/bin/python2.7

py38 is the virtual environment folder for python3.8
I would be glad if you can help me out on this directories, folders stuff because Im noob.

[AastaLLL]

Hi,

Could you try the below script instead?
Please update the Python version based on your requirement.

No cuda support after compiling opencv with cuda

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…

Thanks.