opencv mat 常用操作

Mat(int rows, int cols, int type);
Mat(Size size, int type);
Mat(int rows, int cols, int type, const Scalar& s);
Mat(int rows, int cols, int type, void* data, size_t step=AUTO_STEP);
void create(int rows, int cols, int type);
Mat reshape(int cn, int rows=0) const;
template<typename _Tp, int n> explicit Mat(const Vec<_Tp, n>& vec, bool copyData=true);