本示例主要测试了directshow、Emgucv的视频流采集功能,其中Emgucv还实现了人脸的识别。示例源码下载
实现原理:directshow可以将摄像头的数据流以事件的方式实时传递给程序,程序在此事件中拿到流后可以保存为图片(流可以经过多个filterGraph2对象)。directshow提供将数据绑定到picturebox控件上。以下为打开一个摄像头的步骤:
此控件可以在网上搜索,即好下载,名称为DirectShowLib-2005,它是directshow的.net版本的封装.
代码如下:
int hr = 0;
this.filterGraph2 = (IFilterGraph2)new FilterGraph();
this.captureGraphBuilder2 = (ICaptureGraphBuilder2)new CaptureGraphBuilder2();
this.mediaControl = (IMediaControl)this.filterGraph2;
this.videoWindow = (IVideoWindow)this.filterGraph2;
DsError.ThrowExceptionForHR(hr);
说明:
int hr = 0;
IEnumMoniker classEnum = null;
IMoniker[] moniker = new IMoniker[1];
object source = null;
ICreateDevEnum devEnum = (ICreateDevEnum)new CreateDevEnum();
hr = devEnum.CreateClassEnumerator(FilterCategory.VideoInputDevice, out classEnum, 0);
DsError.ThrowExceptionForHR(hr);
Marshal.ReleaseComObject(devEnum);
if (classEnum == null)
throw new Exception("classEnum is null");
if (classEnum.Next(moniker.Length, moniker, IntPtr.Zero) == 0)
{
Guid iid = typeof(IBaseFilter).GUID;
moniker[0].BindToObject(null, null, ref iid, out source); //moniker绑定以 ibasefilter和object上
}
Marshal.ReleaseComObject(moniker[0]);
Marshal.ReleaseComObject(classEnum);
return (IBaseFilter)source;
找到视频摄像头,将转换为一个IBaseFilter对象。
将IBaseFilter对象加入到filterGraph2对象上,作为第一层视频的过滤,后面会放到picturebox控件上。然后再加入SampleGrabber对象,用于捕获每一帧的视频数据。
此步代码较多,就不在贴代码,后面给出源码下载地址.
int hr = 0;
hr = this.videoWindow.put_Owner(this.pictureBox.Handle);
DsError.ThrowExceptionForHR(hr);
hr = this.videoWindow.put_WindowStyle(WindowStyle.Child);
DsError.ThrowExceptionForHR(hr);
hr = this.videoWindow.put_Visible(OABool.True);
DsError.ThrowExceptionForHR(hr);
System.Drawing.Rectangle rc = this.pictureBox.ClientRectangle;
hr = this.videoWindow.SetWindowPosition(0, 0, 640, 480);
DsError.ThrowExceptionForHR(hr);
emgucv是opencv的.net版本封装,并且opencv获取视频流的方式也是采用的directshow。由于进行了封装,打开和识别人像就极为简单了。
至此,还需复制相关的dll到开发项目中:
private VideoCapture capture;
private Mat mat;
private Common.DetectFace detectFace;
public Form1()
{
InitializeComponent();
CvInvoke.UseOpenCL = false;
detectFace = new Common.DetectFace();
}
private void Form1_Load(object sender, EventArgs e)
{
capture = new Emgu.CV.VideoCapture();
capture.ImageGrabbed += Capture_ImageGrabbed;
capture.Start();
}
private void Capture_ImageGrabbed(object sender, EventArgs e)
{
if (capture != null && capture.Ptr != IntPtr.Zero)
{
mat = new Mat();
capture.Retrieve(mat, 0);
var ls = detectFace.Detect(mat);
foreach(var face in ls)
{
CvInvoke.Rectangle(mat, face, new Bgr(Color.Red).MCvScalar, 2);
}
imageBox1.Image = mat;
}
}
说明: