SURF feature detector in CSharp

From Emgu CV: OpenCV in .NET (C#, VB, C++ and more)
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<font color=green>This project is part of the Emgu.CV.Example solution</font>

System Requirement

Component Requirement Detail
Emgu CV Version Alpha
Operation System Cross Platform

Source Code

<source lang="csharp"> using System; using System.Collections.Generic; using System.Windows.Forms; using System.Drawing; using Emgu.CV; using Emgu.CV.UI; using Emgu.CV.CvEnum; using Emgu.CV.Structure;

namespace SURFFeatureExample {

  static class Program
     /// <summary>
     /// The main entry point for the application.
     /// </summary>
     static void Main()
     static void Run()
        MCvSURFParams surfParam = new MCvSURFParams(500, false);
        Image<Gray, Byte> modelImage = new Image<Gray, byte>("box.png");
        //extract features from the object image
        SURFFeature[] modelFeatures = modelImage.ExtractSURF(ref surfParam);
        Image<Gray, Byte> observedImage = new Image<Gray, byte>("box_in_scene.png");
        // extract features from the observed image
        SURFFeature[] imageFeatures = observedImage.ExtractSURF(ref surfParam);
        //Create a SURF Tracker using k-d Tree
        SURFTracker tracker = new SURFTracker(modelFeatures);
        //Comment out above and uncomment below if you wish to use spill-tree instead
        //SURFTracker tracker = new SURFTracker(modelFeatures, 50, .7, .1);
        SURFTracker.MatchedSURFFeature[] matchedFeatures = tracker.MatchFeature(imageFeatures, 2, 20);
        matchedFeatures = SURFTracker.VoteForUniqueness(matchedFeatures, 0.8);
        matchedFeatures = SURFTracker.VoteForSizeAndOrientation(matchedFeatures, 1.5, 20);
        HomographyMatrix homography = SURFTracker.GetHomographyMatrixFromMatchedFeatures(matchedFeatures);
        //Merge the object image and the observed image into one image for display
        Image<Gray, Byte> res = modelImage.ConcateVertical(observedImage);
        #region draw lines between the matched features
        foreach (SURFTracker.MatchedSURFFeature matchedFeature in matchedFeatures)
           PointF p =;
           p.Y += modelImage.Height;
           res.Draw(new LineSegment2DF(matchedFeature.ModelFeatures[0], p), new Gray(0), 1);
        #region draw the project region on the image
        if (homography != null)
        {  //draw a rectangle along the projected model
           Rectangle rect = modelImage.ROI;
           PointF[] pts = new PointF[] { 
              new PointF(rect.Left, rect.Bottom),
              new PointF(rect.Right, rect.Bottom),
              new PointF(rect.Right, rect.Top),
              new PointF(rect.Left, rect.Top)};
           for (int i = 0; i < pts.Length; i++)
              pts[i].Y += modelImage.Height;
           res.DrawPolyline(Array.ConvertAll<PointF, Point>(pts, Point.Round), true, new Gray(255.0), 5);

} </source>