internal static extern ContourScanner cvStartFindContours( Arr image, MemStorage storage, int header_size, ContourRetrieval mode, ContourApproximation method, Point offset);
internal static extern Seq cvApproxChains( Seq src_seq, MemStorage storage, ContourApproximation method, double parameter, int minimal_perimeter, int recursive);
internal static extern int cvFindContours( Arr image, MemStorage storage, out Seq first_contour, int header_size, ContourRetrieval mode, ContourApproximation method, Point offset);