displaying Point3DCollection with Helixtoolkit c#

Question

I have made my point cloud using the code from the librealsense:

var points = pc.Process(depthFrame).As<Points>();
//float depth = depthFrame.GetDistance(x, y);
//bbox = (287, 23, 86, 320);
// We colorize the depth frame for visualization purposes
var colorizedDepth = colorizer.Process<VideoFrame>(depthFrame).DisposeWith(frames);
//var org = Cv2.ImRead(colorFrame);
// CopyVertices is extensible, any of these will do:
//var vertices = new float[points.Count * 3];
var vertices = new Intel.RealSense.Math.Vertex[points.Count];
// var vertices = new UnityEngine.Vector3[points.Count];
// var vertices = new System.Numerics.Vector3[points.Count]; // SIMD
// var vertices = new GlmSharp.vec3[points.Count];
//var vertices = new byte[points.Count * 3 * sizeof(float)];
points.CopyVertices(vertices);

And I have converted the point cloud to a Point3DCollection from Media3D:

Point3DCollection pointss = new Point3DCollection();
foreach (var vertex in vertices)
{
    var point3D = new Point3D(vertex.x, vertex.y, vertex.z);
    pointss.Add(point3D);
}

I want to display those points using this line in the XAML file:

<h:HelixViewport3D Grid.ColumnSpan="1" Grid.Column="1" Margin="2.4,1,0,-0.4" >
<h:DefaultLights/>
<h:PointsVisual3D Points="{Binding pointss}" Color="Red" Size ="2"/>
</h:HelixViewport3D>

But I don't see my point cloud. Is there something wrong with my code? The code that I am using right now looks like this. I have added what was given in the answer But I get the error object reference is not set on an example of an object. The code I am using is below:

namespace Intel.RealSense
{
    /// <summary>
    /// Interaction logic for Window.xaml
    /// </summary>
    public partial class CaptureWindow : System.Windows.Window
    {
        private Pipeline pipeline;
        private Colorizer colorizer;
        private CancellationTokenSource tokenSource = new CancellationTokenSource();
        private Pipeline pipe = new Pipeline();
        private PointCloud pc = new PointCloud();
        private ThresholdFilter threshold;
        private Point3DCollection _pointss;
        public Point3DCollection pointss
        {
            get => _pointss;
            set
            {
                if (_pointss == value)
                    return;

                _pointss = value;
                OnPropertyChanged();
            }
        }
        public event PropertyChangedEventHandler PropertyChanged;

        protected virtual void OnPropertyChanged(string propertyName = null)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }
        //static CvTrackbar Track;
        //static OpenCvSharp.Point[][] contours;
        //static HierarchyIndex[] hierarchy;
        static Action<VideoFrame> UpdateImage(Image img)
        {
            var wbmp = img.Source as WriteableBitmap;
            return new Action<VideoFrame>(frame =>
            {
                var rect = new Int32Rect(0, 0, frame.Width, frame.Height);
                wbmp.WritePixels(rect, frame.Data, frame.Stride * frame.Height, frame.Stride);
            });
        }
        public CaptureWindow()
        {
            InitializeComponent();
            ModelImporter import = new ModelImporter();
            
            try
            {
                Action<VideoFrame> updateDepth;
                Action<VideoFrame> updateColor;

                // The colorizer processing block will be used to visualize the depth frames.
                colorizer = new Colorizer();

                // Create and config the pipeline to strem color and depth frames.
                pipeline = new Pipeline();

                var cfg = new Config();
                cfg.EnableStream(Stream.Depth, 640, 480);
                cfg.EnableStream(Stream.Color, Format.Rgb8);

                var pp = pipeline.Start(cfg);
                PipelineProfile selection = pp;
                var depth_stream = selection.GetStream<VideoStreamProfile>(Stream.Depth);
                Intrinsics i = depth_stream.GetIntrinsics();
                float[] fov = i.FOV;
                SetupWindow(pp, out updateDepth, out updateColor);

                Task.Factory.StartNew(() =>
                {
                    while (!tokenSource.Token.IsCancellationRequested)
                    {
                        threshold = new ThresholdFilter();
                        threshold.Options[Option.MinDistance].Value = 0.0F;
                        threshold.Options[Option.MaxDistance].Value = 0.1F;
                        using (var releaser = new FramesReleaser())
                        {
                            using (var frames = pipeline.WaitForFrames().DisposeWith(releaser))
                            {
                                var pframes = frames
                                .ApplyFilter(threshold).DisposeWith(releaser);
                            }
                        }
                        // We wait for the next available FrameSet and using it as a releaser object that would track
                        // all newly allocated .NET frames, and ensure deterministic finalization
                        // at the end of scope. 
                        using (var frames = pipeline.WaitForFrames())
                        {
                            var colorFrame = frames.ColorFrame.DisposeWith(frames);
                            var depthFrame = frames.DepthFrame.DisposeWith(frames);
                            var points = pc.Process(depthFrame).As<Points>();
                            //float depth = depthFrame.GetDistance(x, y);
                            //bbox = (287, 23, 86, 320);

                            // We colorize the depth frame for visualization purposes
                            var colorizedDepth = colorizer.Process<VideoFrame>(depthFrame).DisposeWith(frames);
                            //var org = Cv2.ImRead(colorFrame);
                            // CopyVertices is extensible, any of these will do:
                            //var vertices = new float[points.Count * 3];
                            var vertices = new Intel.RealSense.Math.Vertex[points.Count];
                            // var vertices = new UnityEngine.Vector3[points.Count];
                            // var vertices = new System.Numerics.Vector3[points.Count]; // SIMD
                            // var vertices = new GlmSharp.vec3[points.Count];
                            //var vertices = new byte[points.Count * 3 * sizeof(float)];
                            points.CopyVertices(vertices);
                            //Point3DCollection pointss = new Point3DCollection();
foreach (var vertex in vertices)
                            {
var point3D = new Point3D(vertex.x, vertex.y, vertex.z);
pointss.Add(point3D);
}

                            // Render the frames.
                            Dispatcher.Invoke(DispatcherPriority.Render, updateDepth, colorizedDepth);
                            Dispatcher.Invoke(DispatcherPriority.Render, updateColor, colorFrame);

                            Dispatcher.Invoke(new Action(() =>
                            {
                                String depth_dev_sn = depthFrame.Sensor.Info[CameraInfo.SerialNumber];
                                txtTimeStamp.Text = depth_dev_sn + " : " + String.Format("{0,-20:0.00}", depthFrame.Timestamp) + "(" + depthFrame.TimestampDomain.ToString() + ")";
                            }));
                            //HelixToolkit.Wpf.
                        }
                    }
                }, tokenSource.Token);
            }
            catch (Exception ex)
            {
                System.Windows.MessageBox.Show(ex.Message);
                System.Windows.Application.Current.Shutdown();
            }
        }
        private void control_Closing(object sender, System.ComponentModel.CancelEventArgs e)
        {
            tokenSource.Cancel();
        }

private void SetupWindow(PipelineProfile pipelineProfile, out Action<VideoFrame> depth, out Action<VideoFrame> color)
{
using (var p = pipelineProfile.GetStream(Stream.Depth).As<VideoStreamProfile>())
                imgDepth.Source = new WriteableBitmap(p.Width, p.Height, 96d, 96d, PixelFormats.Rgb24, null);
depth = UpdateImage(imgDepth);

using (var p = pipelineProfile.GetStream(Stream.Color).As<VideoStreamProfile>())
                imgColor.Source = new WriteableBitmap(p.Width, p.Height, 96d, 96d, PixelFormats.Rgb24, null);
color = UpdateImage(imgColor);
        }
}

Answer 1

You can only bind to public properties, not to fields, so you have to define it like this:

public Point3DCollection pointss { get; } = new Point3DCollection();

If you want to reassign the collection at runtime, you should also implement INotifyPropertyChanged, otherwise assigning a new collection will not trigger a binding update and the change will not be reflected in the UI.

public class YourViewModel : INotifyPropertyChanged
{
   private Point3DCollection  _pointss;
   public Point3DCollection pointss
   {
      get => _pointss;
      set
      {
         if (_points == value)
            return;

         _points = value;
         OnPropertyChanged();
      }
   }

   public event PropertyChangedEventHandler PropertyChanged;

   protected virtual void OnPropertyChanged(string propertyName = null)
   {
      PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
   }
}