How to select only outer contours with OpenCV?

Question

.NET

Guys, I use OpenCV in my program, I find contours perfectly, BUT both external and internal ones get there. I know that only external ones can be distinguished, I will be grateful for a hint?

CvContourScanner scanner = new CvContourScanner(gray, storage, CvContour.SizeOf, ContourRetrieval.Tree, ContourChain.ApproxSimple);
                        
foreach (CvSeq<CvPoint> c in scanner) 
{
etc....
}

Answer 1

In general, the findContours function has a mode parameter that allows you to pass a hierarchy of contours.
If you have your own function, looking at the findContours sorts can help.