SURF feature detector in CSharp

This project is part of the Emgu.CV.Example solution

System Requirement

Component	Requirement	Detail
Emgu CV	Version 2.0.0.0 Alpha
Operation System	Cross Platform

Source Code

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>
      [STAThread]
      static void Main()
      {
         Application.EnableVisualStyles();
         Application.SetCompatibleTextRenderingDefault(false);
         Run();
      }

      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 = matchedFeature.ObservedFeature.Point.pt;
            p.Y += modelImage.Height;
            res.Draw(new LineSegment2DF(matchedFeature.ModelFeatures[0].Point.pt, p), new Gray(0), 1);
         }
         #endregion

         #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)};
            homography.ProjectPoints(pts);

            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);
         }
         #endregion

         ImageViewer.Show(res);
      }
   }
}

Result