I tried to build OpenCV 3.1.0 on my Raspberry Pi 2B. Unfortunetly, when I trying:
cmake -D CMAKE_BUILD_TYPE=RELEASE \\ -D CMAKE_INSTALL_PREFIX=/usr/lo
The reason is you have used two version of cmake to generate the Makefile.
cd /path/to/opencv rm -rf build mkdir build cd build cmake ..
that will be work fine.