| OpenCV 4.3.0 Open Source Computer Vision

Installation in MacOS

The following steps have been tested for MacOSX (Mavericks) but should work with other versions as well.

## Required Packages

- CMake 3.9 or higher
- Git
- Python 2.7 or later and Numpy 1.5 or later

This tutorial will assume you have Python, Numpy and Git installed on your machine.

Note
  OSX comes with Python 2.7 by default, you will need to install Python 3.8 if you want to use it specifically.
  If you XCode and XCode Command Line-Tools installed, you already have git installed on your machine.

## Installing CMake

1. Find the version for your system and download CMake from their release's page
2. Install the dmg package and launch it from Applications. That will give you the UI app of CMake
3. From the CMake app window, choose menu Tools –> Install For Command Line Use.
4. Install folder will be /usr/bin/ by default, submit it by choosing Install command line links.
5. Test that it works by running
   cmake --version

## Getting OpenCV Source Code

You can use the latest stable OpenCV version or you can grab the latest snapshot from our Git repository.

### Getting the Latest Stable OpenCV Version

- Go to our downloads page.
- Download the source archive and unpack it.

### Getting the Cutting-edge OpenCV from the Git Repository

Launch Git client and clone OpenCV repository. If you need modules from OpenCV contrib repository then clone it as well.

For example

cd ~/<my_working_directory>
git clone https://github.com/opencv/opencv.git
git clone https://github.com/opencv/opencv_contrib.git

## Building OpenCV from Source Using CMake

1. Create a temporary directory, which we denote as `<cmake_build_dir>`, where you want to put the generated Makefiles, project files as well the object files and output binaries and enter there.

   For example

   mkdir build_opencv
   cd build_opencv
   Note
     It is good practice to keep clean your source code directories. Create build directory outside of source tree.

2. Configuring. Run `cmake [<some optional parameters>] <path to the OpenCV source directory>`

   For example

   cmake -DCMAKE_BUILD_TYPE=Release -DBUILD_EXAMPLES=ON ../opencv

   or cmake-gui

   - set full path to OpenCV source code, e.g. `/home/user/opencv`
   - set full path to `<cmake_build_dir>`, e.g. `/home/user/build_opencv`
   - set optional parameters
   - run: "Configure"
   - run: "Generate"
3. Description of some parameters
   - build type: `CMAKE_BUILD_TYPE=Release` (or `Debug`)
   - to build with modules from opencv_contrib set `OPENCV_EXTRA_MODULES_PATH` to `<path to opencv_contrib>/modules`
   - set `BUILD_DOCS=ON` for building documents (doxygen is required)
   - set `BUILD_EXAMPLES=ON` to build all examples
4. [optional] Building python. Set the following python parameters:
   - `PYTHON3_EXECUTABLE = <path to python>`
   - `PYTHON3_INCLUDE_DIR = /usr/include/python<version>`
   - `PYTHON3_NUMPY_INCLUDE_DIRS = /usr/lib/python<version>/dist-packages/numpy/core/include/`
     Note
       To specify Python2 versions, you can replace `PYTHON3_` with `PYTHON2_` in the above parameters.

5. Build. From build directory execute make, it is recommended to do this in several threads

   For example

   make -j7 # runs 7 jobs in parallel
6. To use OpenCV in your CMake-based projects through `find_package(OpenCV)` specify `OpenCV_DIR=<path_to_build_or_install_directory>` variable.

Note
  You can also use a package manager like Homebrew or pip to install releases of OpenCV only (Not the cutting edge).