How to display webcam images captured with Emgu?

Question

I\'m currently working on a project that use Facial Recognition. I therefore need a way to display the webcam images to the user so he can adjust his face.

I\'ve bee

Answer 1

If you are using WPF and MVVM here is how you would do it using EMGU.

View:

<Window x:Class="HA.FacialRecognition.Enroll.Views.PhotoCaptureView"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Window1" Width="800" Height="600">
<Grid>
    <Image Width="640" Height="480" Source="{Binding CurrentFrame}">
        <Image.Clip>
            <EllipseGeometry  RadiusX="240" RadiusY="240">
                <EllipseGeometry.Center>
                    <Point X="320" Y="240" />
                </EllipseGeometry.Center>
            </EllipseGeometry>
        </Image.Clip>
    </Image>
</Grid>

Viewmodel:

namespace HA.FacialRecognition.Enroll.ViewModels
{
public class PhotoCaptureViewModel : INotifyPropertyChanged
{
    public PhotoCaptureViewModel()
    {
        StartVideo();
    }

    private DispatcherTimer Timer { get; set; }

    private Capture Capture { get; set; }

    private BitmapSource _currentFrame;
    public BitmapSource CurrentFrame
    {
        get { return _currentFrame; }
        set
        {
            if (_currentFrame != value)
            {
                _currentFrame = value;
                OnPropertyChanged();
            }
        }
    }

    private void StartVideo()
    {
        Capture = new Capture();
        Timer = new DispatcherTimer();
        //framerate of 10fps
        Timer.Interval = TimeSpan.FromMilliseconds(100);
        Timer.Tick += new EventHandler(async (object s, EventArgs a) =>
        {
            //draw the image obtained from camera
            using (Image<Bgr, byte> frame = Capture.QueryFrame())
            {
                if (frame != null)
                {
                    CurrentFrame = ToBitmapSource(frame);
                }
            }
        });
        Timer.Start();
    }

    public static BitmapSource ToBitmapSource(IImage image)
    {
        using (System.Drawing.Bitmap source = image.Bitmap)
        {
            IntPtr ptr = source.GetHbitmap(); //obtain the Hbitmap
            BitmapSource bs = System.Windows.Interop.Imaging.CreateBitmapSourceFromHBitmap(ptr, IntPtr.Zero, Int32Rect.Empty, BitmapSizeOptions.FromEmptyOptions());
            DeleteObject(ptr); //release the HBitmap
            return bs;
        }
    }

    /// <summary>
    /// Delete a GDI object
    /// </summary>
    [DllImport("gdi32")]
    private static extern int DeleteObject(IntPtr o);

    //implementation of INotifyPropertyChanged, viewmodel disposal etc

}

Answer 2

I reckon all you're looking for is this:

Image<Bgr, Byte> frame = capture.QueryFrame();
pictureBox1.Image = image.ToBitmap(pictureBox1.Width, pictureBox1.Height);

Answer 3

Image Class has got a UriSource property that you may be looking for

Answer 4

I believe you have to use interop (source):

using System.Windows.Interop;
using System.Windows.Media.Imaging;

public static ImageSource AsImageSource<TColor, TDepth>(
    this Image<TColor, TDepth> image) where TColor : IColor, new()
{
    return Imaging.CreateBitmapSourceFromHBitmap(image.Bitmap.GetHbitmap(),
                       IntPtr.Zero, Int32Rect.Empty,
                       BitmapSizeOptions.FromEmptyOptions());
}

Which could be used like this:

void timer_Elapsed(object sender, ElapsedEventArgs e)
{
        using (Image<Bgr, byte> frame = capture.QueryFrame())
        {
                if (frame != null)
                {
                        var bmp = frame.AsImageSource();
                }
        }
}

If the interop doesn't perform well enough, take a look at the source of Image.ToBitmap and Image.get_Bitmap to see how you could implement your own WriteableBitmap.

Answer 5

http://blogs.microsoft.co.il/blogs/tamir/archive/2008/04/23/webcam-control-with-wpf-or-how-to-create-high-framerate-player-with-directshow-by-using-interopbitmap-in-wpf-application.aspx

Answer 6

Look on the Emgu wiki -> Tutorials -> Examples -> WPF (Windows Presentation Foundation) It contains the following code snippet to convert your IImage to a BitmapSource, which you can directly apply to your control.

using Emgu.CV; using System.Runtime.InteropServices; ...

    /// <summary>
    /// Delete a GDI object
    /// </summary>
    /// <param name="o">The poniter to the GDI object to be deleted</param>
    /// <returns></returns>
    [DllImport("gdi32")]
    private static extern int DeleteObject(IntPtr o);

    /// <summary>
    /// Convert an IImage to a WPF BitmapSource. The result can be used in the Set Property of Image.Source
    /// </summary>
    /// <param name="image">The Emgu CV Image</param>
    /// <returns>The equivalent BitmapSource</returns>
    public static BitmapSource ToBitmapSource(IImage image)
    {
        using (System.Drawing.Bitmap source = image.Bitmap)
        {
            IntPtr ptr = source.GetHbitmap(); //obtain the Hbitmap

            BitmapSource bs = System.Windows.Interop.Imaging.CreateBitmapSourceFromHBitmap(
                ptr,
                IntPtr.Zero,
                Int32Rect.Empty,
                System.Windows.Media.Imaging.BitmapSizeOptions.FromEmptyOptions());

            DeleteObject(ptr); //release the HBitmap
            return bs;
        }
    }