I actually installed: CUDA 4.0, Cmake 2.8.2 and i downloaded 2.3.1 version of opencv. But at configuring in Cmake, it give me some errors like this:
CMake Error: The following variables are used in this project, but they are set to NOTFOUND. Please set them or make sure they are set and tested correctly in the CMake files: CUDA_npp_LIBRARY (ADVANCED) linked by target "opencv_gpu" in directory C:/OpenCV-2.3.1/opencv/modules/gpu
despite it detect cuda but it does not configure.