如何使用python绑定从源代码构建OpenCV？

Question

我需要从源代码构建OpenCV，而且空间有限，所以我必须在模块的基础上构建OpenCV (reference.html -构建有限的模块集)。好的，做好，做得好。

通过python可以更容易地使用这些OpenCV模块，因此我添加了cmake -D BUILD_opencv_python3=ON，但是make install并没有创建我期望的prefix/lib/pythonX.Y/site-packages目录。据我所知，这里没有与python相关的选项，只有一个CMake选项。

如何在基于模块的基础上构建OpenCV的python(3)绑定？安装完毕后，如何设置环境以使python -c "import cv2"与我的自定义OpenCV一起工作？

更新

在jetson上运行ubuntu L4T。CMake输出：

--   Python 3:
--     Interpreter:                 /usr/bin/python3 (ver 3.6.9)
--     Libraries:                   NO
--     numpy:                       /home/me/.local/lib/python3.6/site-packages/numpy/core/include (ver 1.19.5)
--     install path:                -

所以我猜空安装路径隐藏了一个问题.但是grep -ni OPENCV_PYTHON3_INSTALL_PATH CMakeCache.txt什么也不返回。

此时，我尝试添加cmake -DOPENCV_PYTHON3_INSTALL_PATH=~/Programs/opencv/local/lib/python3.6/site-packages/，在cmake输出(空白安装路径)中仍然没有添加任何内容，但是

grep -ni OPENCV_PYTHON3_INSTALL_PATH CMakeCache.txt 
1076:OPENCV_PYTHON3_INSTALL_PATH:UNINITIALIZED=~/Programs/opencv/local/lib/python3.6/site-packages/

在make install之后(没有sudo -我没有根权限，需要本地安装)，我在本地安装中没有python绑定。

..。任何线索都将不胜感激！

注:在L4T ubuntu上编译opencv-4.5.4

Answer 1

cmake -DBUILD_LIST=python3 ..解决了这个问题:获得干净的安装目录，包括python packages目录。

Answer 2

我想添加到赛尔的答案，我使用的GitHub吉斯特和它的工作，但我必须放下我所有的垃圾cmake标志。

这是我最终的结局。

cmake \
    -D CMAKE_BUILD_TYPE=RELEASE \
    -D CMAKE_INSTALL_PREFIX=$(python3 -c "import sys; print(sys.prefix)") \
    -D INSTALL_PYTHON_EXAMPLES=ON \
    -D INSTALL_C_EXAMPLES=ON \
    -D WITH_TBB=ON \
    -D WITH_CUDA=OFF \
    -D BUILD_opencv_cudacodec=OFF \
    -D ENABLE_FAST_MATH=1 \
    -D CUDA_FAST_MATH=1 \
    -D WITH_CUBLAS=1 \
    -D WITH_V4L=ON \
    -D WITH_QT=OFF \
    -D WITH_OPENGL=ON \
    -D WITH_GSTREAMER=ON \
    -D OPENCV_GENERATE_PKGCONFIG=ON \
    -D OPENCV_PC_FILE_NAME=opencv.pc \
    -D OPENCV_ENABLE_NONFREE=ON \
    -D OPENCV_PYTHON3_INSTALL_PATH=$(python3 -c "from distutils.sysconfig import get_python_lib; print(get_python_lib())") \
    -D OPENCV_EXTRA_MODULES_PATH=/tmp/opencv_contrib/modules \
    -D PYTHON_EXECUTABLE=$(which python3) \
    -D BUILD_EXAMPLES=ON ..

这是通用的Config输出

-- General configuration for OpenCV 4.5.5 =====================================
--   Version control:               4.5.5
-- 
--   Extra modules:
--     Location (extra):            /tmp/opencv_contrib/modules
--     Version control (extra):     4.5.5
-- 
--   Platform:
--     Timestamp:                   2022-01-23T08:47:55Z
--     Host:                        Linux 5.11.0-41-generic x86_64
--     CMake:                       3.18.2
--     CMake generator:             Unix Makefiles
--     CMake build tool:            /usr/bin/make
--     Configuration:               RELEASE
-- 
--   CPU/HW features:
--     Baseline:                    SSE SSE2 SSE3
--       requested:                 SSE3
--     Dispatched code generation:  SSE4_1 SSE4_2 FP16 AVX AVX2 AVX512_SKX
--       requested:                 SSE4_1 SSE4_2 AVX FP16 AVX2 AVX512_SKX
--       SSE4_1 (18 files):         + SSSE3 SSE4_1
--       SSE4_2 (2 files):          + SSSE3 SSE4_1 POPCNT SSE4_2
--       FP16 (1 files):            + SSSE3 SSE4_1 POPCNT SSE4_2 FP16 AVX
--       AVX (5 files):             + SSSE3 SSE4_1 POPCNT SSE4_2 AVX
--       AVX2 (33 files):           + SSSE3 SSE4_1 POPCNT SSE4_2 FP16 FMA3 AVX AVX2
--       AVX512_SKX (8 files):      + SSSE3 SSE4_1 POPCNT SSE4_2 FP16 FMA3 AVX AVX2 AVX_512F AVX512_COMMON AVX512_SKX
-- 
--   C/C++:
--     Built as dynamic libs?:      YES
--     C++ standard:                11
--     C++ Compiler:                /usr/bin/c++  (ver 9.3.0)
--     C++ flags (Release):         -fsigned-char -ffast-math -W -Wall -Werror=return-type -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point -Wformat -Werror=format-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 -Wno-long-long -pthread -fomit-frame-pointer -ffunction-sections -fdata-sections  -msse -msse2 -msse3 -fvisibility=hidden -fvisibility-inlines-hidden -O3 -DNDEBUG  -DNDEBUG
--     C++ flags (Debug):           -fsigned-char -ffast-math -W -Wall -Werror=return-type -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point -Wformat -Werror=format-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 -Wno-long-long -pthread -fomit-frame-pointer -ffunction-sections -fdata-sections  -msse -msse2 -msse3 -fvisibility=hidden -fvisibility-inlines-hidden -g  -O0 -DDEBUG -D_DEBUG
--     C Compiler:                  /usr/bin/cc
--     C flags (Release):           -fsigned-char -ffast-math -W -Wall -Werror=return-type -Werror=address -Werror=sequence-point -Wformat -Werror=format-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 -Wno-long-long -pthread -fomit-frame-pointer -ffunction-sections -fdata-sections  -msse -msse2 -msse3 -fvisibility=hidden -O3 -DNDEBUG  -DNDEBUG
--     C flags (Debug):             -fsigned-char -ffast-math -W -Wall -Werror=return-type -Werror=address -Werror=sequence-point -Wformat -Werror=format-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 -Wno-long-long -pthread -fomit-frame-pointer -ffunction-sections -fdata-sections  -msse -msse2 -msse3 -fvisibility=hidden -g  -O0 -DDEBUG -D_DEBUG
--     Linker flags (Release):      -Wl,--exclude-libs,libippicv.a -Wl,--exclude-libs,libippiw.a   -Wl,--gc-sections -Wl,--as-needed  
--     Linker flags (Debug):        -Wl,--exclude-libs,libippicv.a -Wl,--exclude-libs,libippiw.a   -Wl,--gc-sections -Wl,--as-needed  
--     ccache:                      NO
--     Precompiled headers:         NO
--     Extra dependencies:          dl m pthread rt
--     3rdparty dependencies:
-- 
--   OpenCV modules:
--     To be built:                 aruco barcode bgsegm bioinspired calib3d ccalib core datasets dnn dnn_objdetect dnn_superres dpm face features2d flann fuzzy gapi hfs highgui img_hash imgcodecs imgproc intensity_transform line_descriptor mcc ml objdetect optflow phase_unwrapping photo plot python3 quality rapid reg rgbd saliency 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:                 alphamat cudaarithm cudabgsegm cudacodec cudafeatures2d cudafilters cudaimgproc cudalegacy cudaobjdetect cudaoptflow cudastereo cudawarping cudev cvv freetype hdf java julia matlab ovis python2 sfm viz
--     Applications:                tests perf_tests examples apps
--     Documentation:               NO
--     Non-free algorithms:         YES
-- 
--   GUI:                           NONE
--     GTK+:                        NO
--     OpenGL support:              NO
--     VTK support:                 NO
-- 
--   Media I/O: 
--     ZLib:                        /usr/lib/x86_64-linux-gnu/libz.so (ver 1.2.11)
--     JPEG:                        /usr/lib/x86_64-linux-gnu/libjpeg.so (ver 80)
--     WEBP:                        build (ver encoder: 0x020f)
--     PNG:                         /usr/lib/x86_64-linux-gnu/libpng.so (ver 1.6.37)
--     TIFF:                        /usr/lib/x86_64-linux-gnu/libtiff.so (ver 42 / 4.1.0)
--     JPEG 2000:                   build (ver 2.4.0)
--     OpenEXR:                     build (ver 2.3.0)
--     HDR:                         YES
--     SUNRASTER:                   YES
--     PXM:                         YES
--     PFM:                         YES
-- 
--   Video I/O:
--     DC1394:                      NO
--     FFMPEG:                      YES
--       avcodec:                   YES (58.54.100)
--       avformat:                  YES (58.29.100)
--       avutil:                    YES (56.31.100)
--       swscale:                   YES (5.5.100)
--       avresample:                YES (4.0.0)
--     GStreamer:                   YES (1.16.2)
--     v4l/v4l2:                    YES (linux/videodev2.h)
-- 
--   Parallel framework:            TBB (ver 2020.1 interface 11101)
-- 
--   Trace:                         YES (with Intel ITT)
-- 
--   Other third-party libraries:
--     Intel IPP:                   2020.0.0 Gold [2020.0.0]
--            at:                   /tmp/opencv/build/3rdparty/ippicv/ippicv_lnx/icv
--     Intel IPP IW:                sources (2020.0.0)
--               at:                /tmp/opencv/build/3rdparty/ippicv/ippicv_lnx/iw
--     VA:                          NO
--     Lapack:                      NO
--     Eigen:                       NO
--     Custom HAL:                  NO
--     Protobuf:                    build (3.19.1)
-- 
--   OpenCL:                        YES (no extra features)
--     Include path:                /tmp/opencv/3rdparty/include/opencl/1.2
--     Link libraries:              Dynamic load
-- 
--   Python 3:
--     Interpreter:                 /home/user/miniconda3/bin/python3 (ver 3.9.5)
--     Libraries:                   /home/user/miniconda3/lib/libpython3.9.so (ver 3.9.5)
--     numpy:                       /home/user/miniconda3/lib/python3.9/site-packages/numpy/core/include (ver 1.21.2)
--     install path:                /home/user/miniconda3/lib/python3.9/site-packages/cv2/python-3.9
-- 
--   Python (for build):            /home/user/miniconda3/bin/python3
-- 
--   Java:                          
--     ant:                         NO
--     JNI:                         NO
--     Java wrappers:               NO
--     Java tests:                  NO
-- 
--   Install to:                    /home/user/miniconda3
-- -----------------------------------------------------------------
-- 
-- Configuring done
-- Generating done
-- Build files have been written to: /tmp/opencv/build

仅作为文档，这就是我在ubuntu20.04上安装的内容。

apt-get update && apt-get install git openssh-client curl wget sudo \
    build-essential pkg-config libboost-system-dev libboost-thread-dev libboost-program-options-dev libboost-test-dev \
    libgl1-mesa-glx libglib2.0-0 \
    libjpeg-dev libpng-dev libtiff-dev \
    libavcodec-dev libavformat-dev libswscale-dev libavresample-dev \
    libgstreamer1.0-dev libgstreamer-plugins-base1.0-dev \
    libxvidcore-dev x264 libx264-dev libfaac-dev libmp3lame-dev libtheora-dev \
    libfaac-dev libmp3lame-dev libvorbis-dev \
    libtbb-dev libatlas-base-dev gfortran -y

Answer 3

若要进行py绑定，请确保接近末尾的config输出具有Python 3节，即

Python 3:
    Interpreter:                 /home/user/anaconda3/envs/cv451/bin/python3 (ver 3.8.12)
    Libraries:                   /home/user/anaconda3/envs/cv451/lib/libpython3.8.so (ver 3.8.12)
    numpy:                       /home/user/anaconda3/envs/cv451/lib/python3.8/site-packages/numpy/core/include (ver 1.21.2)
    install path:                /home/user/anaconda3/envs/cv451/lib/python3.8/site-packages/cv2/python-3.8

对我来说，那部分一开始就不见了。我的问题是python版本在lib (从系统中找到)和解释器(来自conda env)之间不匹配。

因此，就我的情况而言，解决办法是：

1. 让cmake找到conda env的python而不是系统的python：

CMAKE_LIBRARY_PATH=/home/user/anaconda3/envs/cv451/lib cmake /path/to/opencv/arc

1. 默认情况下，绑定被安装到系统的python中。若要指定python路径，请使用cmake标志OPENCV_PYTHON3_INSTALL_PATH：

-D OPENCV_PYTHON3_INSTALL_PATH=/home/user/anaconda3/envs/cv451/lib/python3.8/site-packages/

1. 请记住在编译后安装

sudo make install

参考：

• https://gist.github.com/raulqf/f42c718a658cddc16f9df07ecc627be7
• https://qengineering.eu/install-opencv-4.5-on-jetson-nano.html