Required Packages

• GCC 4.4.x or later
• CMake 2.8.7 or higher
• Git
• GTK+2.x or higher, including headers (libgtk2.0-dev)
• pkg-config
• Python 2.6 or later and Numpy 1.5 or later with developer packages (python-dev, python-numpy)
• ffmpeg or libav development packages: libavcodec-dev, libavformat-dev, libswscale-dev
• [optional] libtbb2 libtbb-dev
• [optional] libdc1394 2.x
• [optional] libjpeg-dev, libpng-dev, libtiff-dev, libjasper-dev, libdc1394-22-dev

The packages can be installed using a terminal and the following commands or by using Synaptic Manager:

[compiler] sudo apt-get install build-essential
[required] sudo apt-get install cmake git libgtk2.0-dev pkg-config libavcodec-dev libavformat-dev libswscale-dev
[optional] sudo apt-get install python-dev python-numpy libtbb2 libtbb-dev libjpeg-dev libpng-dev libtiff-dev libjasper-dev libdc1394-22-dev

Getting OpenCV Source Code

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

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

   cd ~/opencv
   mkdir build
   cd build
   

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

   For example

   cmake -D CMAKE_BUILD_TYPE=Release -D CMAKE_INSTALL_PREFIX=/usr/local ..
   

   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/opencv/build
   • set optional parameters
   • run: “Configure”
   • run: “Generate”

3. Description of some parameters

   • build type: CMAKE_BUILD_TYPE=Release\Debug
   • to build with modules from opencv_contrib set OPENCV_EXTRA_MODULES_PATH to <path to opencv_contrib/modules/>
   • set BUILD_DOCS for building documents
   • set BUILD_EXAMPLES to build all examples

4. [optional] Building python. Set the following python parameters:

   • PYTHON2(3)_EXECUTABLE = <path to python>
   • PYTHON_INCLUDE_DIR = /usr/include/python<version>
   • PYTHON_INCLUDE_DIR2 = /usr/include/x86_64-linux-gnu/python<version>
   • PYTHON_LIBRARY = /usr/lib/x86_64-linux-gnu/libpython<version>.so
   • PYTHON2(3)_NUMPY_INCLUDE_DIRS = /usr/lib/python<version>/dist-packages/numpy/core/include/

5. [optional] Building java.

   • Unset parameter: BUILD_SHARED_LIBS
   • It is useful also to unset BUILD_EXAMPLES, BUILD_TESTS, BUILD_PERF_TESTS - as they all will be statically linked with OpenCV and can take a lot of memory.

6. Build. From build directory execute make, recomend to do it in several threads

   For example

   make -j7 # runs 7 jobs in parallel
   

7. [optional] Building documents. Enter <cmake_build_dir/doc/> and run make with target “html_docs”

   For example

   cd ~/opencv/build/doc/
   make -j7 html_docs
   

8. To install libraries, from build directory execute

   sudo make install
   

9. [optional] Running tests

   • Get the required test data from OpenCV extra repository.

   For example

   git clone https://github.com/Itseez/opencv_extra.git
   

   • set OPENCV_TEST_DATA_PATH environment variable to <path to opencv_extra/testdata>.
   • execute tests from build directory.

   For example

   <cmake_build_dir>/bin/opencv_test_core
   

#include <stdio.h>
#include <opencv2/opencv.hpp>

using namespace cv;

int main(int argc, char** argv )
{
    if ( argc != 2 )
    {
        printf("usage: DisplayImage.out <Image_Path>\n");
        return -1;
    }

    Mat image;
    image = imread( argv[1], 1 );

    if ( !image.data )
    {
        printf("No image data \n");
        return -1;
    }
    namedWindow("Display Image", WINDOW_AUTOSIZE );
    imshow("Display Image", image);

    waitKey(0);

    return 0;
}

cmake_minimum_required(VERSION 2.8)
project( DisplayImage )
find_package( OpenCV REQUIRED )
include_directories( ${OpenCV_INCLUDE_DIRS} )
add_executable( DisplayImage DisplayImage.cpp )
target_link_libraries( DisplayImage ${OpenCV_LIBS} )

cd <DisplayImage_directory>
cmake .
make

./DisplayImage lena.jpg