brew tap homebrew/science
The tap command allows Homebrew to tap into another repository of formulae. Once you've done this you've expanded your options of installable software.
These additional Git repos (inside usr/local/Library/Taps) describe sets of package formulae that are available for installation.
homebrew/science 中有两个版本的 opencv，分别是
stable 220.127.116.11 版本的，另一个是
stable 3.2.0 版本的，你可以通过
brew info 命令查看它们的具体信息。
~/ » brew info opencv3 homebrew/science/opencv3: stable 3.2.0 (bottled), HEAD [keg-only] Open source computer vision library, version 3 http://opencv.org/ Not installed From: https://github.com/Homebrew/homebrew-science/blob/master/opencv3.rb ==> Dependencies Build: cmake ✘, pkg-config ✔ Required: jpeg ✔, libpng ✔, libtiff ✔ Recommended: eigen ✘, openexr ✘, numpy ✘ Optional: ffmpeg ✘, gphoto2 ✘, gstreamer ✘, jasper ✘, libdc1394 ✘, openni ✘, openni2 ✘, qt5 ✘, tbb ✘, vtk ✘ ==> Requirements Optional: cuda ✘, java ✘, python3 ✔ ==> Options --c++11 Build using C++11 mode --with-contrib Build "extra" contributed modules --with-cuda Build with CUDA v7.0+ support --with-examples Install C and python examples (sources) --with-ffmpeg Build with ffmpeg support --with-gphoto2 Build with gphoto2 support --with-gstreamer Build with gstreamer support --with-jasper Build with jasper support --with-java Build with Java support --with-libdc1394 Build with libdc1394 support --with-nonfree Enable non-free algorithms --with-opengl Build with OpenGL support (must use --with-qt5) --with-openni Build with openni support --with-openni2 Build with openni2 support --with-python3 Build with python3 support --with-qt5 Build the Qt5 backend to HighGUI --with-quicktime Use QuickTime for Video I/O instead of QTKit --with-static Build static libraries --with-tbb Enable parallel code in OpenCV using Intel TBB --with-vtk Build with vtk support --without-eigen Build without eigen support --without-numpy Use a numpy you've installed yourself instead of a Homebrew-packaged numpy --without-opencl Disable GPU code in OpenCV using OpenCL --without-openexr Build without openexr support --without-python Build without Python support --without-test Build without accuracy & performance tests --HEAD Install HEAD version ==> Caveats This formula is keg-only, which means it was not symlinked into /usr/local. opencv3 and opencv install many of the same files.
然后，根据 info 命令列出的编译选项，组织适合自己需求的命令(参数放opencv3右边会被忽略)：
~/ » brew install --with-examples --with-contrib --with-python3 opencv3
This formula is keg-only, which means it was not symlinked into /usr/local. opencv3 and opencv install many of the same files. If you need to have this software first in your PATH run: echo 'export PATH="/usr/local/opt/opencv3/bin:$PATH"' >> ~/.zshrc For compilers to find this software you may need to set: LDFLAGS: -L/usr/local/opt/opencv3/lib CPPFLAGS: -I/usr/local/opt/opencv3/include For pkg-config to find this software you may need to set: PKG_CONFIG_PATH: /usr/local/opt/opencv3/lib/pkgconfig If you need Python to find bindings for this keg-only formula, run: echo /usr/local/opt/opencv3/lib/python2.7/site-packages >> /usr/local/lib/python2.7/site-packages/opencv3.pth
export PATH="$PATH:/usr/local/opt/opencv3/bin" export PYTHONPATH="$PYTHONPATH:/usr/local/opt/opencv3/lib/python3.6/site-packages"
source ~/.zshrc 后，打开 python3 解释器确认是否能够导入 cv2 模块：
Python 3.6.1 (default, Mar 23 2017, 16:49:06)