I have created a WPF application in .NET 4.6.1. to display video from the frame grabbing event for a machine vision camera.

In XAML there is an image control bound to a WriteableBitmap

<Image x:Name="CameraImage" Grid.Column="1" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Source="{Binding CameraImage}"/> 

In the code-behind:

public event PropertyChangedEventHandler PropertyChanged; protected void NotifyPropertyChanged([CallerMemberName] string propertyName = null) {     //Console.WriteLine(propertyName);     PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName)); }  private WriteableBitmap cameraImage; private IntPtr cameraImagePtr; public WriteableBitmap CameraImage {     get { return cameraImage; }     set     {         cameraImage = value;         cameraImagePtr = cameraImage.BackBuffer;         NotifyPropertyChanged();     } } 

The WriteableBitmap is initialised as so:

CameraImage = new WriteableBitmap(2448, 2048, 0, 0, PixelFormats.Bgr24, null); 

In the grab event generated by the camera we have:

// Occurs when an image has been acquired and is ready to be processed. private void OnImageGrabbed(Object sender, ImageGrabbedEventArgs e) {     try     {         // Get the grab result.         IGrabResult grabResult = e.GrabResult;          // Check if the image can be displayed.         if (grabResult.IsValid)         {             byte[] buffer = grabResult.PixelData as byte[];              converter.OutputPixelFormat = PixelType.BGR8packed;             lock(cameraImage)             {                 // Converts camera Bayer array image to BGR image and saves at cameraImagePtr                 converter.Convert(cameraImagePtr, 2448 * 2048 * 3, grabResult);             }                                  // Make WriteableBitmap dirty (on UI thread) so that the WPF Image control redraws             Dispatcher.Invoke(new Action(() =>             {                 cameraImage.Lock();                 cameraImage.AddDirtyRect(new Int32Rect(0, 0, cameraImage.PixelWidth, cameraImage.PixelHeight));                 cameraImage.Unlock();             }), DispatcherPriority.Render);         }     }     catch (Exception exception)     {         Console.WriteLine(exception.Message);         throw exception;     }     finally     {         // Dispose the grab result if needed for returning it to the grab loop.         e.DisposeGrabResultIfClone();     } } 

Questions

• I can’t just pass cameraImage.BackBuffer to the writing (Converter.convert()) function, I have to do cameraImagePtr = cameraImage.BackBuffer; and then use cameraImagePtr. Why is that?

• The fans on my laptop spin up when this is running – it seems like it is using a lot of CPU. Is there a more efficient way? From what I can tell I am not making extra copies of the frame.