centeredGradient  217 modules/video/src/tvl1flow.cpp bool cv_ocl_tvl1flow::centeredGradient(const UMat &src, UMat &dx, UMat &dy)
centeredGradient  682 modules/video/src/tvl1flow.cpp void centeredGradient(const Mat_<float>& src, Mat_<float>& dx, Mat_<float>& dy)