Mat. FindContours Method (Point[] [] ,HierarchyIndex[] , ContourRetrieval, ContourChain, Nullable< Point> ) OpenCvSharp Class Library
Finds contours in a binary image. The source is an 8-bit single-channel image. Non-zero pixels are treated as 1’s. Zero pixels remain 0’s, so the image is treated as binary. The function modifies this image while extracting the contours.

Namespace:  OpenCvSharp.CPlusPlus
Assembly:  OpenCvSharp.CPlusPlus (in OpenCvSharp.CPlusPlus.dll) Version: 1.0.0.0 (1.0.0.0)
Syntax

public void FindContours(
	out Point[][] contours,
	out HierarchyIndex[] hierarchy,
	ContourRetrieval mode,
	ContourChain method,
	Nullable<Point> offset = null
)

Parameters

contours
Type:OpenCvSharp.CPlusPlus.Point[][]
Detected contours. Each contour is stored as a vector of points.
hierarchy
Type:OpenCvSharp.CPlusPlus.HierarchyIndex[]
Optional output vector, containing information about the image topology. It has as many elements as the number of contours. For each i-th contour contours[i], the members of the elements hierarchy[i] are set to 0-based indices in contours of the next and previous contours at the same hierarchical level, the first child contour and the parent contour, respectively. If for the contour i there are no next, previous, parent, or nested contours, the corresponding elements of hierarchy[i] will be negative.
mode
Type: OpenCvSharp.ContourRetrieval
Contour retrieval mode
method
Type: OpenCvSharp.ContourChain
Contour approximation method
offset (Optional)
Type: System.Nullable<Point>
Optional offset by which every contour point is shifted. This is useful if the contours are extracted from the image ROI and then they should be analyzed in the whole image context.
See Also

Reference