internal static extern IntPtr cvGetDiag(Arr arr, out _CvMat submat, int diag);
internal static extern IntPtr cvGetCols(Arr arr, out _CvMat submat, int start_col, int end_col);
internal static extern IntPtr cvGetRows(Arr arr, out _CvMat submat, int start_row, int end_row, int delta_row);
internal static extern IntPtr cvGetSubRect(Arr arr, out _CvMat submat, Rect rect);
internal static extern IntPtr cvReshape( Arr arr, out _CvMat header, int new_cn, int new_rows);
internal static extern IntPtr cvGetMat(Arr arr, out _CvMat header, out int coi, int allowND);