Erosion operator from Mathematical Morphology with 3x3 structuring element.

The filter represents an optimized version of Erosion filter, which is aimed for grayscale image processing with 3x3 structuring element.

See Erosion filter, which represents generic version of erosion filter supporting custom structuring elements and wider range of image formats.

The filter accepts 8 bpp grayscale images for processing.

Inheritance: BaseUsingCopyPartialFilter
        public void Video_NewFrame(object sender, NewFrameEventArgs eventArgs)
        {
            UnmanagedImage image = UnmanagedImage.FromManagedImage((Bitmap) eventArgs.Frame.Clone());

            var extractChannel = new ExtractChannel(RGB.R);
            UnmanagedImage channel = extractChannel.Apply(image);
            //		UnmanagedImage originalRed = channel.Clone();
            if (true) {
                var threshold = new Threshold(200);
                threshold.ApplyInPlace(channel);

                ////filter to convert RGB image to 8bpp gray scale for image processing
                //IFilter gray_filter = new GrayscaleBT709();
                //gray_image = gray_filter.Apply(gray_image);

                ////thresholding a image
                //Threshold th_filter = new Threshold(color_data.threshold);
                //th_filter.ApplyInPlace(gray_image);

                //erosion filter to filter out small unwanted pixels
                Erosion3x3 erosion = new Erosion3x3();
                erosion.ApplyInPlace(channel);

                //dilation filter
                //Dilatation3x3 dilatation = new Dilatation3x3();
                //dilatation.ApplyInPlace(channel);

                //GrayscaleToRGB filter = new GrayscaleToRGB();
                //image = filter.Apply(channel);

                //ReplaceChannel replaceFilter = new ReplaceChannel(RGB.B, channel);
                //replaceFilter.ApplyInPlace(image);
            }

            BlobCounter bc = new BlobCounter();
            //arrange blobs by area
            bc.ObjectsOrder = ObjectsOrder.Area;
            bc.FilterBlobs = true;
            bc.MinHeight = minObjectSize;
            bc.MinWidth = minObjectSize;
            bc.MaxHeight = maxObjectSize;
            bc.MaxWidth = maxObjectSize;

            //process image for blobs
            bc.ProcessImage(channel);
            channel.Dispose();

            //	if (motionDetector.ProcessFrame(image) > 0.02) {
            //	for (int i = 0; i < blobCountingObjectsProcessing.ObjectRectangles.Length; i++) {
            Rectangle[] rectangles = bc.GetObjectsRectangles();
            Blob[] blobs = bc.GetObjectsInformation();
            for (int i = 0; i < bc.ObjectsCount; i++) {
                Rectangle rectangle = rectangles[i];
                int width = rectangle.Width;
                int height = rectangle.Height;

            //		if (width < maxObjectSize && height < maxObjectSize && width > minObjectSize && height > minObjectSize) {
                    Drawing.Rectangle(image, rectangle, colorList[i % colorList.Length]);

                    if (i == 0) {
                        Position = GetCenterOfMass(image, rectangle);
                        Drawing.FillRectangle(image, rectangle, Color.BlanchedAlmond);
                        Drawing.FillRectangle(image, new Rectangle((int) Position.U - dotSize, (int) Position.V - dotSize, dotSize * 3, dotSize * 3), Color.Indigo);
                    }
            //		}
            }
            //	}

            Image = image.ToManagedImage();
            //	videoForm.ImageDestination.Image = image.ToManagedImage();
        }
        static void Main(string[] args)
        {
            Threshold thresh = new Threshold(10);
            Median median = new Median(9);
            Erosion3x3 erode = new Erosion3x3();
            Dilatation3x3 dilate = new Dilatation3x3();
            GrahamConvexHull hullFinder = new GrahamConvexHull();
            ConnectedComponentsLabeling ccLabeler = new ConnectedComponentsLabeling();
            BorderFollowing contourFinder = new BorderFollowing();
            GrayscaleToRGB rgb = new GrayscaleToRGB();
            ConvexHullDefects defectFinder = new ConvexHullDefects(10);

            Bitmap img = (Bitmap)Bitmap.FromFile("hand3.jpg");

            Bitmap image = Grayscale.CommonAlgorithms.BT709.Apply(img);
            thresh.ApplyInPlace(image);
            //median.ApplyInPlace(image);
            erode.ApplyInPlace(image);
            dilate.ApplyInPlace(image);

            BlobCounter counter = new BlobCounter(image);
            counter.ObjectsOrder = ObjectsOrder.Area;

            Blob[] blobs = counter.GetObjectsInformation();

            if (blobs.Length > 0)
            {
                counter.ExtractBlobsImage(image, blobs[0], true);

                UnmanagedImage hand = blobs[0].Image;

                var contour = contourFinder.FindContour(hand);

                if (contour.Count() > 0)
                {
                    var initialHull = hullFinder.FindHull(contour);

                    var defects = defectFinder.FindDefects(contour, initialHull);

                    var filteredHull = initialHull.ClusterHullPoints().FilterLinearHullPoints();

                    var palmCenter = defects.Centroid(contour);

                    var wristPoints = filteredHull.SelectWristPoints(defects, contour);

                    Bitmap color = rgb.Apply(hand).ToManagedImage();

                    //BitmapData data = color.LockBits(new Rectangle(0, 0, color.Width, color.Height), ImageLockMode.ReadWrite, color.PixelFormat);
                    //Drawing.Polyline(data, contour, Color.Blue);
                    //Drawing.Polygon(data, filteredHull, Color.Red);
                    //color.UnlockBits(data);

                    Graphics gr = Graphics.FromImage(color);

                    gr.DrawPolygon(new Pen(Brushes.Red, 3), filteredHull.ToPtArray());
                    gr.DrawLines(new Pen(Brushes.Blue, 3), contour.ToPtArray());
                    gr.DrawEllipse(new Pen(Brushes.Red, 3), palmCenter.X - 10, palmCenter.Y - 10, 20, 20);

                    foreach (ConvexityDefect defect in defects)
                    {
                        gr.DrawEllipse(new Pen(Brushes.Green, 6), contour[defect.Point].X - 10, contour[defect.Point].Y - 10, 20, 20);
                    }

                    foreach (AForge.IntPoint pt in filteredHull)
                    {
                        gr.DrawEllipse(new Pen(Brushes.Yellow, 6), pt.X - 10, pt.Y - 10, 20, 20);
                    }

                    foreach (AForge.IntPoint pt in wristPoints)
                    {
                        gr.DrawEllipse(new Pen(Brushes.PowderBlue, 6), pt.X - 10, pt.Y - 10, 20, 20);
                    }

                    ImageBox.Show(color);
                }
            }
        }