template<class T> struct type2cv {};
template<> struct type2cv<uint8_t>  { static const int value = CV_8U;  };
template<> struct type2cv<int8_t>   { static const int value = CV_8S;  };
template<> struct type2cv<uint16_t> { static const int value = CV_16U; };
template<> struct type2cv<int16_t>  { static const int value = CV_16S; };
template<> struct type2cv<int32_t>  { static const int value = CV_32S; };
template<> struct type2cv<float>    { static const int value = CV_32F; };
template<> struct type2cv<double>   { static const int value = CV_64F; };