如何显示用 Emgu 拍摄的网络摄像头图像？

Question

我目前正在开展一个使用面部识别的项目。 因此，我需要一种向用户显示网络摄像头图像的方法，以便他可以调整自己的脸。

我一直在尝试使用尽可能少的 CPU 从网络摄像头获取图像：

• VideoRendererElement
• WPFMediaKit
• DirectShow-Lib

但是它们都不是很好...要么太慢要么太消耗 CPU 资源。

然后我尝试了Emgu library，感觉很棒。 起初，我在一个 Windows 窗体项目中进行了尝试，并在 Picture Box 中更新了图像。 但是，当我尝试将它集成到我的 WPF 项目中时，我陷入了如何将我的图像传递给我的图像控件的问题..

现在，我有以下源代码：

<Window x:Class="HA.FacialRecognition.Enroll.Window1"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="Window1" Width="800" Height="600"
        Loaded="Window_Loaded" Closing="Window_Closing">
    <Grid>
        <Image x:Name="webcam" Width="640" Height="480" >
            <Image.Clip>
                <EllipseGeometry  RadiusX="240" RadiusY="240">
                    <EllipseGeometry.Center>
                        <Point X="320" Y="240" />
                    </EllipseGeometry.Center>
                </EllipseGeometry>
            </Image.Clip>
        </Image>
    </Grid>
</Window>

以及背后的代码：

private Capture capture;
private System.Timers.Timer timer;

public Window1()
{
    InitializeComponent();
}

private void Window_Loaded(object sender, RoutedEventArgs e)
{
    capture = new Capture();
    capture.FlipHorizontal = true;

    timer = new System.Timers.Timer();
    timer.Interval = 15;
    timer.Elapsed += new ElapsedEventHandler(timer_Elapsed);
    timer.Start();
}

void timer_Elapsed(object sender, ElapsedEventArgs e)
{
    using (Image<Bgr, byte> frame = capture.QueryFrame())
    {
        if (frame != null)
        {
            var bmp = frame.Bitmap;
            // How do I pass this bitmap to my Image control called "webcam"?
        }
    }
}

private void Window_Closing(object sender, CancelEventArgs e)
{
    if (capture != null)
    {
        capture.Dispose();
    }
}

我的猜测是使用 BitmapSource/WriteableBitmap 但我没有让它们工作......

谢谢！

Answer 1

Image 类有一个你可能正在寻找的 UriSource 属性

Answer 2

查看 Emgu wiki -> 教程 -> 示例 -> WPF (Windows Presentation Foundation) 它包含以下代码 sn-p 将您的 IImage 转换为 BitmapSource，您可以直接将其应用于您的控件。

使用 Emgu.CV； 使用 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;
        }
    }

Answer 3

我想你要找的是这个：

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

Answer 4

如果您使用的是 WPF 和 MVVM，这里是使用 EMGU 的方法。

查看：

<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>

视图模型：

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 5

我相信你必须使用互操作（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());
}

可以这样使用：

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

如果互操作性能不够好，请查看Image.ToBitmap 和Image.get_Bitmap 的源代码，了解如何实现自己的WriteableBitmap。

Answer 6

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 7

试试这个。

http://easywebcam.codeplex.com/

我用过，非常棒..