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I need to build OpenCV from source and I have limited space, so, I have to build OpenCV on a module basis (https://docs.opencv.org/4.x/db/d05/tutorial_config_reference.html - Build limited set of modules). OK, cmake and make work fine.
Would be easier to use these OpenCV modules from python so I add cmake -D BUILD_opencv_python3=ON but make install does not create the prefix/lib/pythonX.Y/site-packages directory I expected. There is no python related option but only a CMake option as far as I understand the doc.
How to get python(3) binding for OpenCV when building it on a module basis ?
Once installed, how to set up environnement to get python -c "import cv2" to work with my custom-built OpenCV ?
UPDATE
Running ubuntu L4T on jetson. CMake outputs :
-- 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: -
So I guess empty install path hides a problem behind... But grep -ni OPENCV_PYTHON3_INSTALL_PATH CMakeCache.txt returns nothing.
At this point, I tried to add cmake -DOPENCV_PYTHON3_INSTALL_PATH=~/Programs/opencv/local/lib/python3.6/site-packages/, still nothing in cmake output (blank install path) but
grep -ni OPENCV_PYTHON3_INSTALL_PATH CMakeCache.txt
1076:OPENCV_PYTHON3_INSTALL_PATH:UNINITIALIZED=~/Programs/opencv/local/lib/python3.6/site-packages/
And after make install (without sudo - I don't have root privilege and need local install), I have no python binding in the local install.
... Any clue would be appreciated !
Note: compiling opencv-4.5.4 on L4T ubuntu
380
I wanted to add to CYL answer, I use that GitHub Gist and it works, but I have to drop all my junk cmake flags.
Here is what I ultimately end up with.
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 ..
and this is the General Config output
-- 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
Just for documentation, this is what I install on the ubuntu 20.04.
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
answered Jul 29 '26 09:07
What works for me is, note that you may have to change Python paths if not using python 3.11:
-D BUILD_opencv_python2=OFF \
-D BUILD_opencv_python3=ON \
-D PYTHON_VERSION=311 \
-D PYTHON_DEFAULT_EXECUTABLE=/usr/bin/python3.11 \
-D PYTHON3_EXECUTABLE=/usr/bin/python3.11 \
-D PYTHON3_PACKAGES_PATH=/usr/lib/python3/dist-packages \
-D PYTHON3_INCLUDE_DIR=/usr/include/python3.11 \
-D OPENCV_PYTHON3_INSTALL_PATH=/usr/local/lib/python3.11/dist-packages \
-D PYTHON3_NUMPY_INCLUDE_DIRS=/usr/local/lib/python3.11/dist-packages/numpy/core/include \
And the full cmake command in case it could help:
cmake -D CMAKE_BUILD_TYPE=Release \
-D CMAKE_INSTALL_PREFIX=/usr/local \
-D WITH_TBB=ON \
-D ENABLE_FAST_MATH=1 \
-D CUDA_FAST_MATH=1 \
-D WITH_CUBLAS=1 \
-D WITH_CUDA=ON \
-D BUILD_opencv_cudacodec=OFF \
-D WITH_CUDNN=ON \
-D OPENCV_DNN_CUDA=ON \
-D CUDA_ARCH_BIN="5.3 6.0 6.1 7.0 7.5 8.0 8.6" \
-D CUDA_GENERATION=Auto \
-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_EXTRA_MODULES_PATH=/workspaces/ocr-c++/opencv_contrib/modules \
-D BUILD_opencv_python2=OFF \
-D BUILD_opencv_python3=ON \
-D PYTHON_VERSION=311 \
-D PYTHON_DEFAULT_EXECUTABLE=/usr/bin/python3.11 \
-D PYTHON3_EXECUTABLE=/usr/bin/python3.11 \
-D PYTHON3_PACKAGES_PATH=/usr/lib/python3/dist-packages \
-D PYTHON3_INCLUDE_DIR=/usr/include/python3.11 \
-D OPENCV_PYTHON3_INSTALL_PATH=/usr/local/lib/python3.11/dist-packages \
-D PYTHON3_NUMPY_INCLUDE_DIRS=/usr/local/lib/python3.11/dist-packages/numpy/core/include \
-D BUILD_EXAMPLES=OFF \
-D INSTALL_PYTHON_EXAMPLES=OFF \
-D INSTALL_C_EXAMPLES=OFF \
..
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