ubuntu) installed opencv with cmake but python couldn`t find cv2 module - opencv

Question

i just want to know about this problem.
pkg config show my opencv4 version, but in python3 there`s no module named cv2.
please help me...!
cmake list:
cmake -D CMAKE_BUILD_TYPE=RELEASE -D CMAKE_INSTALL_PREFIX=/usr/local -D INSTALL_PYTHON_EXAMPLES=ON -D INSTALL_C_EXAMPLES=ON -D BUILD_DOCS=OFF -D BUILD_PERF_TESTS=OFF -D BUILD_TESTS=OFF -D BUILD_PACKAGE=OFF -D BUILD_EXAMPLES=OFF -D WITH_TBB=ON -D ENABLE_FAST_MATH=1 -D CUDA_FAST_MATH=1 -D CUDA_TOOLKIT_ROOT_DIR=/usr/local/cuda-11.7 -D WITH_CUDA=ON -D WITH_CUBLAS=ON -D WITH_CUFFT=ON -D WITH_NVCUVID=ON -D WITH_IPP=OFF -D WITH_V4L=ON -D WITH_1394=OFF -D WITH_GTK=ON -D WITH_QT=OFF -D WITH_OPENGL=ON -D WITH_EIGEN=ON -D WITH_FFMPEG=ON -D WITH_GSTREAMER=ON -D BUILD_JAVA=OFF -D BUILD_opencv_python3=ON -D BUILD_opencv_python2=OFF -D BUILD_NEW_PYTHON_SUPPORT=ON -D OPENCV_SKIP_PYTHON_LOADER=ON -D OPENCV_GENERATE_PKGCONFIG=ON -D OPENCV_ENABLE_NONFREE=ON -D OPENCV_EXTRA_MODULES_PATH=../../opencv_contrib-4.5.1/modules -D WITH_CUDNN=ON -D OPENCV_DNN_CUDA=ON -D CUDA_ARCH_BIN=8.6 -D CUDA_ARCH_PTX=8.6 -D OpenCL_LIBRARY=/usr/local/cuda-11.7/lib64/libOpenCL.so -D OpenCL_INCLUDE_DIR=/usr/local/cuda-11.7/include/ ..
cuda-11.7 cudnn- so.8 opencv-4.5.1

Answer 1

Did you check the build information before building and installing OpenCV? If not, you can still check the build information using the OpenCV function getBuildInformation(). To find your OpenCV configuration, create a C++ file, add the following code to it, and execute the file:
#include <opencv2/opencv.hpp>
int main(void)
{
std::cout << cv::getBuildInformation() << std::endl;
}
Reference: https://learnopencv.com/get-opencv-build-information-getbuildinformation/
Once you have the build information, check the Python3 options (usually found at the bottom of the output). OpenCV Python bindings have not been generated if the install path is unspecified.
That means OpenCV has to be built again with the proper Python3 addresses.
The following options need to be added to the CMake command:
-D PYTHON_EXECUTABLE=$(which python3)
-D OPENCV_PYTHON3_INSTALL_PATH=$(python3 -c "from distutils.sysconfig import get_python_lib; print(get_python_lib())")
-D PYTHON3_INCLUDE_DIR=$(python3 -c "from distutils.sysconfig import get_python_inc; print(get_python_inc())")
-D PYTHON3_PACKAGES_PATH=$(python3 -c "from distutils.sysconfig import get_python_lib; print(get_python_lib())")
Then, run a clean build, and check the configuration page for the correct Python3 options. A step-by-step guide is posted by learnopencv for installing OpenCV DNN module with GPU support on Linux.