Install opencv3.2 on centos7

yum groupinstall "Development Tools" 
yum install cmake gcc gtk2-devel numpy pkconfig

wget https://github.com/opencv/opencv/archive/3.2.0.zip -O opencv-3.2.0.zip
unzip opencv-3.2.0.zip

cd opencv-3.2.0
mkdir build
cd build
cmake -D CMAKE_BUILD_TYPE=DEBUG -D CMAKE_INSTALL_PREFIX=/usr/local ..
make
make install

export PKG_CONFIG_PATH=$PKG_CONFIG_PATH:/usr/local/lib/pkgconfig/
echo '/usr/local/lib/' >> /etc/ld.so.conf.d/opencv.conf
ldconfig

cd ~
wget https://raw.githubusercontent.com/kyshel/template/master/src/hello_cv.cpp 
wget https://raw.githubusercontent.com/kyshel/template/master/file/lena.jpg
g++ -o hello_cv hello_cv.cpp `pkg-config opencv --cflags --libs` && ./hello_cv lena.jpg lena_gray.jpg