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November 18, 2016 12:41
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How to access OpenCV contour hierarchy data through Emgu.
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| using System; | |
| using Emgu.CV; | |
| using Emgu.CV.Util; | |
| namespace OCVContours | |
| { | |
| /// <summary> | |
| /// The contour hierarchy result of OpenCV's FindContours function | |
| /// </summary> | |
| public class ContourData : IDisposable | |
| { | |
| /// <summary> | |
| /// Construct an empty collection. | |
| /// </summary> | |
| public ContourData() | |
| { | |
| Vertices = new VectorOfVectorOfPoint(); | |
| Hierarchy = new Mat(); | |
| } | |
| /// <summary> | |
| /// Construct, taking ownership of the contours and hiearachy OpenCV objects. | |
| /// </summary> | |
| public ContourData(VectorOfVectorOfPoint contours, Mat hierarchy) | |
| { | |
| if (contours == null) | |
| { | |
| throw new ArgumentNullException("ContourData must not have null contours."); | |
| } | |
| if (hierarchy == null) | |
| { | |
| throw new ArgumentNullException("ContourData must not have null hierarchy."); | |
| } | |
| Vertices = contours; | |
| Hierarchy = hierarchy; | |
| } | |
| /// <remarks> | |
| /// Guaranteed to be not-null, because the property is non-asignable and assignment is guaranteed by the constructors. | |
| /// </remarks> | |
| public VectorOfVectorOfPoint Vertices { get; } | |
| /// <summary> | |
| /// For each i-th contour contours[i], the elements hierarchy[i][0], | |
| /// hiearchy[i][1], hiearchy[i][2], and hiearchy[i][3] 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. | |
| /// </summary> | |
| /// <remarks> | |
| /// Guaranteed to be not-null. | |
| /// </remarks> | |
| public Mat Hierarchy { get; } | |
| /// <summary> | |
| /// Get a neighbor index in the heirarchy tree. | |
| /// </summary> | |
| /// <returns> | |
| /// A neighbor index or -1 if the given neighbor does not exist. | |
| /// </returns> | |
| public int Get(HierarchyIndex component, int index) | |
| { | |
| if (Hierarchy.Depth != Emgu.CV.CvEnum.DepthType.Cv32S) | |
| { | |
| throw new ArgumentOutOfRangeException("ContourData must have Cv32S hierarchy element type."); | |
| } | |
| if (Hierarchy.Rows != 1) | |
| { | |
| throw new ArgumentOutOfRangeException("ContourData must have one hierarchy hierarchy row."); | |
| } | |
| if (Hierarchy.NumberOfChannels != 4) | |
| { | |
| throw new ArgumentOutOfRangeException("ContourData must have four hierarchy channels."); | |
| } | |
| if (Hierarchy.Dims != 2) | |
| { | |
| throw new ArgumentOutOfRangeException("ContourData must have two dimensional hierarchy."); | |
| } | |
| long elementStride = Hierarchy.ElementSize / sizeof(Int32); | |
| var offset = (long)component + index * elementStride; | |
| if (0 <= offset && offset < Hierarchy.Total.ToInt64() * elementStride) | |
| { | |
| unsafe | |
| { | |
| return *((Int32*)Hierarchy.DataPointer.ToPointer() + offset); | |
| } | |
| } | |
| else | |
| { | |
| return -1; | |
| } | |
| } | |
| public int Size | |
| { | |
| get | |
| { | |
| var verticesSize = Vertices.Size; | |
| var hierarchySize = Hierarchy.Cols; | |
| if (verticesSize == hierarchySize) | |
| { | |
| return verticesSize; | |
| } | |
| else | |
| { | |
| throw new InvalidOperationException("The ContourData size is undefined because the contour vertices and hierarchy arrays have different length."); | |
| } | |
| } | |
| } | |
| #region IDisposable | |
| protected virtual void Dispose(bool disposing) | |
| { | |
| if (disposing) | |
| { | |
| Vertices.Dispose(); | |
| Hierarchy.Dispose(); | |
| } | |
| } | |
| public void Dispose() | |
| { | |
| Dispose(true); | |
| } | |
| #endregion | |
| } | |
| } |
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Hello, if I want to set a specific contour hierarchy, could I just use the same pointer as Get to set my element ?
Thank you