Guide to build opencv 3.0 in ubuntu 15.04

build_opencv3.txt

1.) Prepare by installing compiler and required library (optional is also installed for this tutorial)
sudo apt-get install build-essential cmake cmake-gui git libgtk2.0-dev pkg-config libavcodec-dev libavformat-dev libswscale-dev python3-dev python3-numpy libtbb2 libtbb-dev libjpeg-dev libpng-dev libtiff-dev libjasper-dev libdc1394-22-dev

2.) Clone the git repo
git clone https://github.com/Itseez/opencv.git

3.) Switch to the 3.0.0 tag
cd opencv/
git checkout 3.0.0

4.) Create the build dir
mkdir build
cd build

5.) Cmake
cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/usr/local ..

6.) GUI cmake
cmake-gui ../

7.) Check options
- make sure BUILD_opencv_python2 and BUILD_opencv_python3 is checked if you want to build for python
- WITH_QT is unchecked (because OpenCV does not support Qt5)
- WITH_OPENMP to enable openmp support
- WITH_CUBLAS for CUDA BLAS support (basic linear algebra system)

8.) Build
make -j4

9.) Install
sudo make install