public List<VectorOfKeyPoint> SURF_BruteForceMatcher(Image<Gray, byte> model, Image<Gray, byte> observed, int hessianThreshould, out SURFDetector surfCPU)
        {
            surfCPU = new SURFDetector(hessianThreshould, false);
            List<VectorOfKeyPoint> KeyPointsList = new List<VectorOfKeyPoint>();
            VectorOfKeyPoint modelKeyPoints;
            VectorOfKeyPoint observedKeyPoints;
            try
            {

                modelKeyPoints = surfCPU.DetectKeyPointsRaw(model, null); // Extract features from the object image
                observedKeyPoints = surfCPU.DetectKeyPointsRaw(observed, null); // Extract features from the observed image

                if (modelKeyPoints.Size <= 0)
                    throw new System.ArgumentException("Can't find any keypoints in your model image!");

                KeyPointsList.Add(modelKeyPoints);
                KeyPointsList.Add(observedKeyPoints);

            }
            catch (Exception e)
            {
                Log.WriteLine("SURF_BruteForceMatcher: " + e.Message);
                Console.WriteLine(e.Message);
                throw e;
            }
            return KeyPointsList;
        }
Exemplo n.º 2
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        public SURFEngine(Emgu.CV.Image<Gray, byte> roi)
        {
            surfDetector = new SURFDetector(500, false);
            itemImage = roi;

            itemKP = surfDetector.DetectKeyPointsRaw(itemImage, null);
            itemDescriptors = surfDetector.ComputeDescriptorsRaw(itemImage, null, itemKP);

            matcher = new BruteForceMatcher<float>(DistanceType.L2);
            matcher.Add(itemDescriptors);
        }
Exemplo n.º 3
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        public List<Keypoint> usingSurf(Bitmap image)
        {
            SURFDetector surf = new SURFDetector(750, false);
            Image<Gray, Byte> modelImage = new Image<Gray, byte>(new Bitmap(image));
            VectorOfKeyPoint modelKeyPoints = surf.DetectKeyPointsRaw(modelImage, null);
            MKeyPoint[] keypoints = modelKeyPoints.ToArray();

            Keypoint key;
            List<Keypoint> keypointsList = new List<Keypoint>();
            foreach (MKeyPoint keypoint in keypoints)
            {
                key = new Keypoint(keypoint.Point.X, keypoint.Point.Y, keypoint.Size);
                keypointsList.Add(key);
            }

            return keypointsList;
        }
Exemplo n.º 4
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        /// <summary>
        /// Draw the model image and observed image, the matched features and homography projection.
        /// </summary>
        /// <param name="modelImage">The model image</param>
        /// <param name="observedImage">The observed image</param>
        /// <param name="matchTime">The output total time for computing the homography matrix.</param>
        /// <returns>The model image and observed image, the matched features and homography projection.</returns>
        public static Image<Bgr, Byte> Draw(Image<Gray, Byte> modelImage, Image<Gray, byte> observedImage, out long matchTime)
        {
            Stopwatch watch;
            HomographyMatrix homography = null;

            SURFDetector surfCPU = new SURFDetector (500, false);
            VectorOfKeyPoint modelKeyPoints;
            VectorOfKeyPoint observedKeyPoints;
            Matrix<int> indices;

            Matrix<byte> mask;
            int k = 2;
            double uniquenessThreshold = 0.8;
            if (GpuInvoke.HasCuda) {
                GpuSURFDetector surfGPU = new GpuSURFDetector (surfCPU.SURFParams, 0.01f);
                using (GpuImage<Gray, Byte> gpuModelImage = new GpuImage<Gray, byte> (modelImage))
                    //extract features from the object image
                using (GpuMat<float> gpuModelKeyPoints = surfGPU.DetectKeyPointsRaw (gpuModelImage, null))
                using (GpuMat<float> gpuModelDescriptors = surfGPU.ComputeDescriptorsRaw (gpuModelImage, null, gpuModelKeyPoints))
                using (GpuBruteForceMatcher<float> matcher = new GpuBruteForceMatcher<float> (DistanceType.L2)) {
                    modelKeyPoints = new VectorOfKeyPoint ();
                    surfGPU.DownloadKeypoints (gpuModelKeyPoints, modelKeyPoints);
                    watch = Stopwatch.StartNew ();

                    // extract features from the observed image
                    using (GpuImage<Gray, Byte> gpuObservedImage = new GpuImage<Gray, byte> (observedImage))
                    using (GpuMat<float> gpuObservedKeyPoints = surfGPU.DetectKeyPointsRaw (gpuObservedImage, null))
                    using (GpuMat<float> gpuObservedDescriptors = surfGPU.ComputeDescriptorsRaw (gpuObservedImage, null, gpuObservedKeyPoints))
                    using (GpuMat<int> gpuMatchIndices = new GpuMat<int> (gpuObservedDescriptors.Size.Height, k, 1, true))
                    using (GpuMat<float> gpuMatchDist = new GpuMat<float> (gpuObservedDescriptors.Size.Height, k, 1, true))
                    using (GpuMat<Byte> gpuMask = new GpuMat<byte> (gpuMatchIndices.Size.Height, 1, 1))
                    using (Stream stream = new Stream ()) {
                        matcher.KnnMatchSingle (gpuObservedDescriptors, gpuModelDescriptors, gpuMatchIndices, gpuMatchDist, k, null, stream);
                        indices = new Matrix<int> (gpuMatchIndices.Size);
                        mask = new Matrix<byte> (gpuMask.Size);

                        //gpu implementation of voteForUniquess
                        using (GpuMat<float> col0 = gpuMatchDist.Col (0))
                        using (GpuMat<float> col1 = gpuMatchDist.Col (1)) {
                            GpuInvoke.Multiply (col1, new MCvScalar (uniquenessThreshold), col1, stream);
                            GpuInvoke.Compare (col0, col1, gpuMask, CMP_TYPE.CV_CMP_LE, stream);
                        }

                        observedKeyPoints = new VectorOfKeyPoint ();
                        surfGPU.DownloadKeypoints (gpuObservedKeyPoints, observedKeyPoints);

                        //wait for the stream to complete its tasks
                        //We can perform some other CPU intesive stuffs here while we are waiting for the stream to complete.
                        stream.WaitForCompletion ();

                        gpuMask.Download (mask);
                        gpuMatchIndices.Download (indices);

                        if (GpuInvoke.CountNonZero (gpuMask) >= 4) {
                            int nonZeroCount = Features2DToolbox.VoteForSizeAndOrientation (modelKeyPoints, observedKeyPoints, indices, mask, 1.5, 20);
                            if (nonZeroCount >= 4)
                                homography = Features2DToolbox.GetHomographyMatrixFromMatchedFeatures (modelKeyPoints, observedKeyPoints, indices, mask, 2);
                        }

                        watch.Stop ();
                    }
                }
            } else {
                //extract features from the object image
                modelKeyPoints = surfCPU.DetectKeyPointsRaw (modelImage, null);
                Matrix<float> modelDescriptors = surfCPU.ComputeDescriptorsRaw (modelImage, null, modelKeyPoints);

                watch = Stopwatch.StartNew ();

                // extract features from the observed image
                observedKeyPoints = surfCPU.DetectKeyPointsRaw (observedImage, null);
                Matrix<float> observedDescriptors = surfCPU.ComputeDescriptorsRaw (observedImage, null, observedKeyPoints);
                BruteForceMatcher<float> matcher = new BruteForceMatcher<float> (DistanceType.L2);
                matcher.Add (modelDescriptors);

                indices = new Matrix<int> (observedDescriptors.Rows, k);
                using (Matrix<float> dist = new Matrix<float> (observedDescriptors.Rows, k)) {
                    matcher.KnnMatch (observedDescriptors, indices, dist, k, null);
                    mask = new Matrix<byte> (dist.Rows, 1);
                    mask.SetValue (255);
                    Features2DToolbox.VoteForUniqueness (dist, uniquenessThreshold, mask);
                }

                int nonZeroCount = CvInvoke.cvCountNonZero (mask);
                if (nonZeroCount >= 4) {
                    nonZeroCount = Features2DToolbox.VoteForSizeAndOrientation (modelKeyPoints, observedKeyPoints, indices, mask, 1.5, 20);
                    if (nonZeroCount >= 4)
                        homography = Features2DToolbox.GetHomographyMatrixFromMatchedFeatures (modelKeyPoints, observedKeyPoints, indices, mask, 2);
                }

                watch.Stop ();
            }

            //Draw the matched keypoints
            Image<Bgr, Byte> result = Features2DToolbox.DrawMatches (modelImage, modelKeyPoints, observedImage, observedKeyPoints,
                                          indices, new Bgr (255, 255, 255), new Bgr (255, 255, 255), mask, Features2DToolbox.KeypointDrawType.DEFAULT);

            #region draw the projected 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);

                result.DrawPolyline (Array.ConvertAll<PointF, Point> (pts, Point.Round), true, new Bgr (Color.Red), 5);
            }
            #endregion

            matchTime = watch.ElapsedMilliseconds;

            return result;
        }
Exemplo n.º 5
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        public Image<Bgr, byte> DrawResult(Image<Gray, byte> modelImage, Image<Gray, byte> observedImage,out double area, int minarea, out Point center)
        {
            //double estimated_dist =99999;
            center = new Point(400, 224);
            area = 0;
            //modelImage.Save("D:\\temp\\modelimage.jpg");
            //observedImage.Save("D:\\temp\\observedimage.jpg");

            //单应矩阵
            HomographyMatrix homography = null;

            //surf算法检测器
            var surfCpu = new SURFDetector(500, false);

            //原图与实际图中的关键点

            Matrix<byte> mask;

            //knn匹配的系数
            var k = 2;
            //滤波系数
            var uniquenessThreshold = 0.8;

            //从标记图中,提取surf特征点与描述子
            var modelKeyPoints = surfCpu.DetectKeyPointsRaw(modelImage, null);
            var modelDescriptors = surfCpu.ComputeDescriptorsRaw(modelImage, null, modelKeyPoints);

            // 从实际图片提取surf特征点与描述子
            var observedKeyPoints = surfCpu.DetectKeyPointsRaw(observedImage, null);
            var observedDescriptors = surfCpu.ComputeDescriptorsRaw(observedImage, null, observedKeyPoints);
            if (observedDescriptors == null)
            {

                return null;
            }

            //使用BF匹配算法,匹配特征向量
            //var bfmatcher = new BruteForceMatcher<float>(DistanceType.L2);
            //bfmatcher.Add(modelDescriptors);
            var indices = new Matrix<int>(observedDescriptors.Rows, k);
            var flannMatcher = new Index(modelDescriptors, 4);
            //通过特征向量筛选匹配对
            using (var dist = new Matrix<float>(observedDescriptors.Rows, k))
            {
                //最近邻2点特征向量匹配
                //bfmatcher.KnnMatch(observedDescriptors, indices, dist, k, null);
                flannMatcher.KnnSearch(observedDescriptors, indices, dist, k, 24);
                //匹配成功的,将特征点存入mask
                mask = new Matrix<byte>(dist.Rows, 1);
                mask.SetValue(255);
                //通过滤波系数,过滤非特征点,剩余特征点存入mask
                Features2DToolbox.VoteForUniqueness(dist, uniquenessThreshold, mask);
            }

            var nonZeroCount = CvInvoke.cvCountNonZero(mask);
            if (nonZeroCount >= 10)
            {
                //过滤旋转与变形系数异常的特征点,剩余存入mask
                nonZeroCount = Features2DToolbox.VoteForSizeAndOrientation(modelKeyPoints, observedKeyPoints, indices,
                    mask, 1.5, 20);
                if (nonZeroCount >= 10)
                    //使用剩余特征点,构建单应矩阵
                    homography = Features2DToolbox.GetHomographyMatrixFromMatchedFeatures(modelKeyPoints,
                        observedKeyPoints, indices, mask, 2);
            }

            // }

            //画出匹配的特征点
            //Image<Bgr, Byte> result = Features2DToolbox.DrawMatches(modelImage, modelKeyPoints, observedImage, observedKeyPoints,indices, new Bgr(0, 0, 255), new Bgr(0, 255, 0), mask, Features2DToolbox.KeypointDrawType.DEFAULT);
            // result.Save("D:\\temp\\matchedpoints.jpg");
            observedImage.ToBitmap();
            var result = Features2DToolbox.DrawMatches(modelImage, modelKeyPoints, observedImage, observedKeyPoints,
                indices, new Bgr(0, 0, 255), new Bgr(0, 255, 0), mask, Features2DToolbox.KeypointDrawType.DEFAULT);

            #region draw the projected region on the Image

            //画出单应矩阵
            if (homography != null)
            {
                var 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)
                    };*/
                var pts = new[]
                {
                    new PointF(rect.Left + (rect.Right - rect.Left)/5, rect.Bottom - (rect.Bottom - rect.Top)/5),
                    new PointF(rect.Right - (rect.Right - rect.Left)/5, rect.Bottom - (rect.Bottom - rect.Top)/5),
                    new PointF(rect.Right - (rect.Right - rect.Left)/5, rect.Top + (rect.Bottom - rect.Top)/5),
                    new PointF(rect.Left + (rect.Right - rect.Left)/5, rect.Top + (rect.Bottom - rect.Top)/5)
                };
                //根据整个图片的旋转、变形情况,计算出原图中四个顶点转换后的坐标,并画出四边形
                homography.ProjectPoints(pts);
                area = Getarea(pts);
                double xsum = 0;
                double ysum = 0;
                foreach (var point in pts)
                {
                    xsum += point.X;
                    ysum += point.Y;
                }
                center = new Point(Convert.ToInt32(xsum / 4), Convert.ToInt32(ysum / 4));
                if (area > minarea)
                {
                    var temp = new Image<Bgr, byte>(result.Width, result.Height);
                    temp.DrawPolyline(Array.ConvertAll(pts, Point.Round), true, new Bgr(Color.Red), 5);
                    //estimated_dist = GetDist(pts);

                    var a = CountContours(temp.ToBitmap());
                    if (a == 2)
                    {
                        result.DrawPolyline(Array.ConvertAll(pts, Point.Round), true, new Bgr(Color.Red), 5);
                        //result.Save("D:\\temp\\" + estimated_dist.ToString() + ".jpg");
                    }
                    else
                    {
                        area = 0; //dst = estimated_dist;
                        return result;
                    }
                }
            }
            else area = 0;

            #endregion

            //dst = estimated_dist;
            return result;
        }
Exemplo n.º 6
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        private void extractData()
        {
            SURFDetector surfCPU = new SURFDetector(500, false);

            _objectKeyPoints = surfCPU.DetectKeyPointsRaw(objectImage, null);
            _objectDescriptors = surfCPU.ComputeDescriptorsRaw(objectImage, null, objectKeyPoints);
        }
Exemplo n.º 7
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        private void PerformSurfDetection(object sender, EventArgs e)
        {
            this.Text = "working...";
            Application.DoEvents();
            stopwatch.Restart();

            HomographyMatrix homographyMatrix = null;
            SURFDetector surfDetector = new SURFDetector(500, false);
            Image<Gray, Byte> imgMasterGray;
            Image<Gray, Byte> imgToFindGray;
            VectorOfKeyPoint vkpMasterKeyPoints;
            VectorOfKeyPoint vkpToFindKeyPoints;
            Matrix<float> mtxMasterDescriptors;
            Matrix<float> mtxToFindDescriptors;
            Matrix<int> mtxMatchIndices;
            Matrix<float> mtxDistance;
            Matrix<Byte> mtxMask;
            BruteForceMatcher<float> bruteForceMatcher;

            int neighbors = 2;
            double ratioUnique = 0.5;
            int nonZeroElements;
            double scaleIncrement = 1.5;
            int rotationBin = 20;
            double maxReprojectionError = 2.0;

            //PointF[] ptfPointsF;
            //Point ptPoints;

            imgMasterGray = new Image<Gray, byte>(imgMasterColor.ToBitmap());
            imgToFindGray = new Image<Gray, byte>(imgToFindColor.ToBitmap());

            vkpMasterKeyPoints = surfDetector.DetectKeyPointsRaw(imgMasterGray, null);
            mtxMasterDescriptors = surfDetector.ComputeDescriptorsRaw(imgMasterGray, null, vkpMasterKeyPoints);

            vkpToFindKeyPoints = surfDetector.DetectKeyPointsRaw(imgToFindGray, null);
            mtxToFindDescriptors = surfDetector.ComputeDescriptorsRaw(imgToFindGray, null, vkpToFindKeyPoints);

            bruteForceMatcher = new BruteForceMatcher<float>(DistanceType.L2);
            bruteForceMatcher.Add(mtxToFindDescriptors);

            mtxMatchIndices = new Matrix<int>(mtxMasterDescriptors.Rows, neighbors);
            mtxDistance = new Matrix<float>(mtxMasterDescriptors.Rows, neighbors);

            bruteForceMatcher.KnnMatch(mtxMasterDescriptors, mtxMatchIndices, mtxDistance, neighbors, null);

            mtxMask = new Matrix<byte>(mtxDistance.Rows, 1);
            mtxMask.SetValue(255);

            Features2DToolbox.VoteForUniqueness(mtxDistance, ratioUnique, mtxMask);

            nonZeroElements = CvInvoke.cvCountNonZero(mtxMask);
            if (nonZeroElements >= 4)
            {
                nonZeroElements = Features2DToolbox.VoteForSizeAndOrientation(vkpToFindKeyPoints, vkpMasterKeyPoints, mtxMatchIndices, mtxMask, scaleIncrement, rotationBin);
                if (nonZeroElements >= 4)
                {
                    homographyMatrix = Features2DToolbox.GetHomographyMatrixFromMatchedFeatures(vkpToFindKeyPoints, vkpMasterKeyPoints, mtxMatchIndices, mtxMask, maxReprojectionError);
                }
            }

            imgCopyToFind = imgToFindColor.Copy();
            imgCopyToFind.Draw(new Rectangle(1, 1, imgCopyToFind.Width - 3, imgCopyToFind.Height - 3), bgrFoundImageColor, 2);

            imgResult = imgMasterColor;
            imgResult = imgResult.ConcateHorizontal(imgCopyToFind);

            if (homographyMatrix != null)
            {
                // draw a rectangle along the projected model
                Rectangle rect = imgCopyToFind.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)
                };

                homographyMatrix.ProjectPoints(pts);

                Point[] ptPoints = { Point.Round(pts[0]), Point.Round(pts[1]), Point.Round(pts[2]), Point.Round(pts[3]) };

                imgResult.DrawPolyline(ptPoints, true, bgrFoundImageColor, 2);

                int X = Convert.ToInt16((pts[0].X + pts[1].X) / 2) + this.Left;
                int Y = Convert.ToInt16((pts[1].Y + pts[2].Y) / 2) + this.Top + 30;

                LeftClick(X, Y);
            }

            stopwatch.Stop();
            //this.Text = "working time = " + stopwatch.Elapsed.TotalSeconds.ToString() + "sec, done ! ";
        }
Exemplo n.º 8
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        private static bool IsModelInObserved( Image<Gray, byte> modelImage, Image<Gray, byte> observedImage, double similarityThreshold = 0.075 )
        {
            var surfCpu = new SURFDetector(500, false);

             Matrix<byte> mask;
             int k = 2;
             double uniquenessThreshold = 0.8;

             //extract features from the object image
             var modelKeyPoints = surfCpu.DetectKeyPointsRaw( modelImage, null );
             Matrix<float> modelDescriptors = surfCpu.ComputeDescriptorsRaw(modelImage, null, modelKeyPoints);

             // extract features from the observed image
             var observedKeyPoints = surfCpu.DetectKeyPointsRaw( observedImage, null );
             Matrix<float> observedDescriptors = surfCpu.ComputeDescriptorsRaw(observedImage, null, observedKeyPoints);
             BruteForceMatcher<float> matcher = new BruteForceMatcher<float>(DistanceType.L2);
             matcher.Add( modelDescriptors );

             var indices = new Matrix<int>( observedDescriptors.Rows, k );
             using ( var dist = new Matrix<float>( observedDescriptors.Rows, k ) )
             {
            matcher.KnnMatch( observedDescriptors, indices, dist, k, null );
            mask = new Matrix<byte>( dist.Rows, 1 );
            mask.SetValue( 255 );
            Features2DToolbox.VoteForUniqueness( dist, uniquenessThreshold, mask );
             }

             int keypointMatchCount = CvInvoke.cvCountNonZero( mask );
             if ( keypointMatchCount >= 4 )
             {
            keypointMatchCount = Features2DToolbox.VoteForSizeAndOrientation( modelKeyPoints, observedKeyPoints, indices, mask, 1.5, 20 );
            if ( keypointMatchCount >= 4 )
            {
               Features2DToolbox.GetHomographyMatrixFromMatchedFeatures( modelKeyPoints, observedKeyPoints, indices, mask, 2 );
            }
             }

             var similarity = (double)keypointMatchCount / observedKeyPoints.Size;
             return similarity > similarityThreshold;
        }
Exemplo n.º 9
0
        public static bool FindModelImageInObservedImage( Image<Gray, byte> modelImage, Image<Gray, byte> observedImage )
        {
            var surfCpu = new SURFDetector(500, false);
             VectorOfKeyPoint modelKeyPoints;
             VectorOfKeyPoint observedKeyPoints;
             Matrix<int> indices;

             Matrix<byte> mask;
             int k = 2;
             double uniquenessThreshold = 0.8;
             if ( GpuInvoke.HasCuda )
             {
            GpuSURFDetector surfGpu = new GpuSURFDetector(surfCpu.SURFParams, 0.01f);
            using ( GpuImage<Gray, byte> gpuModelImage = new GpuImage<Gray, byte>( modelImage ) )
            //extract features from the object image
            using ( GpuMat<float> gpuModelKeyPoints = surfGpu.DetectKeyPointsRaw( gpuModelImage, null ) )
            using ( GpuMat<float> gpuModelDescriptors = surfGpu.ComputeDescriptorsRaw( gpuModelImage, null, gpuModelKeyPoints ) )
            using ( GpuBruteForceMatcher<float> matcher = new GpuBruteForceMatcher<float>( DistanceType.L2 ) )
            {
               modelKeyPoints = new VectorOfKeyPoint();
               surfGpu.DownloadKeypoints( gpuModelKeyPoints, modelKeyPoints );

               // extract features from the observed image
               using ( GpuImage<Gray, byte> gpuObservedImage = new GpuImage<Gray, byte>( observedImage ) )
               using ( GpuMat<float> gpuObservedKeyPoints = surfGpu.DetectKeyPointsRaw( gpuObservedImage, null ) )
               using ( GpuMat<float> gpuObservedDescriptors = surfGpu.ComputeDescriptorsRaw( gpuObservedImage, null, gpuObservedKeyPoints ) )
               using ( GpuMat<int> gpuMatchIndices = new GpuMat<int>( gpuObservedDescriptors.Size.Height, k, 1, true ) )
               using ( GpuMat<float> gpuMatchDist = new GpuMat<float>( gpuObservedDescriptors.Size.Height, k, 1, true ) )
               using ( GpuMat<Byte> gpuMask = new GpuMat<byte>( gpuMatchIndices.Size.Height, 1, 1 ) )
               using ( var stream = new Emgu.CV.GPU.Stream() )
               {
                  matcher.KnnMatchSingle( gpuObservedDescriptors, gpuModelDescriptors, gpuMatchIndices, gpuMatchDist, k, null, stream );
                  indices = new Matrix<int>( gpuMatchIndices.Size );
                  mask = new Matrix<byte>( gpuMask.Size );

                  //gpu implementation of voteForUniquess
                  using ( GpuMat<float> col0 = gpuMatchDist.Col( 0 ) )
                  using ( GpuMat<float> col1 = gpuMatchDist.Col( 1 ) )
                  {
                     GpuInvoke.Multiply( col1, new MCvScalar( uniquenessThreshold ), col1, stream );
                     GpuInvoke.Compare( col0, col1, gpuMask, CMP_TYPE.CV_CMP_LE, stream );
                  }

                  observedKeyPoints = new VectorOfKeyPoint();
                  surfGpu.DownloadKeypoints( gpuObservedKeyPoints, observedKeyPoints );

                  //wait for the stream to complete its tasks
                  //We can perform some other CPU intesive stuffs here while we are waiting for the stream to complete.
                  stream.WaitForCompletion();

                  gpuMask.Download( mask );
                  gpuMatchIndices.Download( indices );

                  if ( GpuInvoke.CountNonZero( gpuMask ) >= 4 )
                  {
                     int nonZeroCount = Features2DToolbox.VoteForSizeAndOrientation(modelKeyPoints, observedKeyPoints, indices, mask, 1.5, 20);
                     if ( nonZeroCount >= 4 )
                     {
                        Features2DToolbox.GetHomographyMatrixFromMatchedFeatures( modelKeyPoints, observedKeyPoints, indices, mask, 2 );
                     }
                     if ( (double)nonZeroCount / mask.Height > 0.02 )
                     {
                        return true;
                     }
                  }
               }
            }
             }
             else
             {
            //extract features from the object image
            modelKeyPoints = surfCpu.DetectKeyPointsRaw( modelImage, null );
            Matrix<float> modelDescriptors = surfCpu.ComputeDescriptorsRaw(modelImage, null, modelKeyPoints);

            // extract features from the observed image
            observedKeyPoints = surfCpu.DetectKeyPointsRaw( observedImage, null );
            Matrix<float> observedDescriptors = surfCpu.ComputeDescriptorsRaw(observedImage, null, observedKeyPoints);
            BruteForceMatcher<float> matcher = new BruteForceMatcher<float>(DistanceType.L2);
            matcher.Add( modelDescriptors );

            indices = new Matrix<int>( observedDescriptors.Rows, k );
            using ( Matrix<float> dist = new Matrix<float>( observedDescriptors.Rows, k ) )
            {
               matcher.KnnMatch( observedDescriptors, indices, dist, k, null );
               mask = new Matrix<byte>( dist.Rows, 1 );
               mask.SetValue( 255 );
               Features2DToolbox.VoteForUniqueness( dist, uniquenessThreshold, mask );
            }

            int nonZeroCount = CvInvoke.cvCountNonZero(mask);
            if ( nonZeroCount >= 4 )
            {
               nonZeroCount = Features2DToolbox.VoteForSizeAndOrientation( modelKeyPoints, observedKeyPoints, indices, mask, 1.5, 20 );
               if ( nonZeroCount >= 4 )
               {
                  Features2DToolbox.GetHomographyMatrixFromMatchedFeatures( modelKeyPoints, observedKeyPoints, indices, mask, 2 );
               }
            }

            if ( (double)nonZeroCount/mask.Height > 0.02 )
            {
               return true;
            }
             }

             //Draw the matched keypoints
             //var result = Features2DToolbox.DrawMatches(modelImage, modelKeyPoints, observedImage, observedKeyPoints, indices, new Bgr(0, 0, 255), new Bgr(255, 0, 0), mask, Features2DToolbox.KeypointDrawType.DEFAULT);
             //result.Save( @"C:\Users\D.Markachev\Desktop\bleh-keypoints.jpg" );

             return false;
        }
        /// <summary>
        /// Draw the model image and observed image, the matched features and homography projection.
        /// </summary>
        /// <param name="modelImageFileName">The model image</param>
        /// <param name="observedImageBitmap">The observed image</param>
        /// <param name="matchTime">The output total time for computing the homography matrix.</param>
        /// <returns>The model image and observed image, the matched features and homography projection.</returns>
        private System.Drawing.Point[] DrawBruteForceMatch(String modelImageFileName, Bitmap observedImageBitmap, out long matchTime)
            {
                try
                {
                    Image<Gray, Byte> modelImage = new Image<Gray, byte>(modelImageFileName);
                    Image<Gray, Byte> observedImage = new Image<Gray, byte>(observedImageBitmap);
                    HomographyMatrix homography = null;
                    Stopwatch watch;
                    SURFDetector surfCPU = new SURFDetector(500, false);
                    VectorOfKeyPoint modelKeyPoints;
                    VectorOfKeyPoint observedKeyPoints;
                    Matrix<int> indices;

                    Matrix<byte> mask;
                    int k = 2;
                    double uniquenessThreshold = 0.8;

                    //extract features from the object image
                    modelKeyPoints = surfCPU.DetectKeyPointsRaw(modelImage, null);
                    Matrix<float> modelDescriptors = surfCPU.ComputeDescriptorsRaw(modelImage, null, modelKeyPoints);

                    watch = Stopwatch.StartNew();

                    // extract features from the observed image
                    observedKeyPoints = surfCPU.DetectKeyPointsRaw(observedImage, null);
                    Matrix<float> observedDescriptors = surfCPU.ComputeDescriptorsRaw(observedImage, null, observedKeyPoints);
                    BruteForceMatcher<float> matcher = new BruteForceMatcher<float>(DistanceType.L2);
                    matcher.Add(modelDescriptors);

                    indices = new Matrix<int>(observedDescriptors.Rows, k);
                    Matrix<float> dist = new Matrix<float>(observedDescriptors.Rows, k);
                    matcher.KnnMatch(observedDescriptors, indices, dist, k, null);
                    mask = new Matrix<byte>(dist.Rows, 1);
                    mask.SetValue(255);
                    Features2DToolbox.VoteForUniqueness(dist, uniquenessThreshold, mask);

                    int nonZeroCount = CvInvoke.cvCountNonZero(mask);
                    if (nonZeroCount >= 4)
                    {
                        nonZeroCount = Features2DToolbox.VoteForSizeAndOrientation(modelKeyPoints, observedKeyPoints, indices, mask, 1.5, 20);
                        if (nonZeroCount >= 4)
                            homography = Features2DToolbox.GetHomographyMatrixFromMatchedFeatures(modelKeyPoints, observedKeyPoints, indices, mask, 2);
                    }
                    watch.Stop();

                    //Draw the matched keypoints
                    Image<Bgr, Byte> result = Features2DToolbox.DrawMatches(modelImage, modelKeyPoints, observedImage, observedKeyPoints,
                                                            indices, new Bgr(255, 255, 255), new Bgr(255, 255, 255), mask, Features2DToolbox.KeypointDrawType.DEFAULT);

                    System.Drawing.Point[] newpts = null;
                    #region draw the projected 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);
                        //result.DrawPolyline(Array.ConvertAll<PointF, System.Drawing.Point>(pts, System.Drawing.Point.Round), true, new Bgr(Color.Red), 2);
                        //result.Save(@"E:\1.jpg");
                        newpts = Array.ConvertAll<PointF, System.Drawing.Point>(pts, System.Drawing.Point.Round);

                    }
                    #endregion
                    matchTime = watch.ElapsedMilliseconds;
                    return newpts;
                }
                catch (Exception e)
                {
                    Console.WriteLine(e.Message);
                    matchTime = 0;
                    return new System.Drawing.Point[] { new System.Drawing.Point(-1, -1), new System.Drawing.Point(-1, -1), new System.Drawing.Point(-1, -1), new System.Drawing.Point(-1, -1) };
                }
        }