emgu cv - DetectMultiScale异常

Question

我尝试使用emgu CV检测图片上的面部，但我遇到了异常

SEHException was unhandled

在

Rectangle[] facesDetected = face.DetectMultiScale(gray, 1.1, 10, new Size(20, 20), Size.Empty);

代码：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using Emgu.CV.Structure;
using Emgu.CV;
using System.Runtime.InteropServices;
using Emgu.CV.GPU;
using Emgu.CV.CvEnum;


namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        Capture capture;
        Image<Bgr, Byte> image;
        bool captureInProgress;
        List<Rectangle> faces = new List<Rectangle>();

        public Form1()
        {
            InitializeComponent();
        }

        void ShowFromCam(object sender, EventArgs e){
            image = capture.QueryFrame();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            if (capture == null)
            {
                try
                {
                    capture = new Capture();

                    CascadeClassifier face = new CascadeClassifier("haarcascade_frontalface_default.xml");
                    Image<Gray, Byte>  gray = capture.RetrieveGrayFrame();
                    Rectangle[] facesDetected = face.DetectMultiScale(
                        gray,               //image
                        1.1,                //scaleFactor
                        10,                 //minNeighbors
                        new Size(20, 20),   //minSize
                        Size.Empty);        //maxSize
                    faces.AddRange(facesDetected);
                    //Draw detected faces
                    foreach (Rectangle face1 in faces)
                        image.Draw(face1, new Bgr(Color.Red), 2);
                }
                catch (NullReferenceException excpt)
                {
                    MessageBox.Show(excpt.Message);
                }
            }

            if (capture != null)
            {
                if (captureInProgress)
                {  //if camera is getting frames then stop the capture and set button Text
                    // "Start" for resuming capture
                    button1.Text = "Start!"; //
                    Application.Idle -= ShowFromCam;
                }
                else
                {
                    //if camera is NOT getting frames then start the capture and set button
                    // Text to "Stop" for pausing capture
                    button1.Text = "Stop";
                    Application.Idle += ShowFromCam;
                }
                captureInProgress = !captureInProgress;
            }
        }
}

详细例外：

System.Runtime.InteropServices.SEHException was unhandled
  Message=External component has thrown an exception.
  Source=Emgu.CV
  ErrorCode=-2147467259
  StackTrace:
       at Emgu.CV.CvInvoke.CvCascadeClassifierDetectMultiScale(IntPtr classifier, IntPtr image, IntPtr objects, Double scaleFactor, Int32 minNeighbors, Int32 flags, Size minSize, Size maxSize)
       at Emgu.CV.CascadeClassifier.DetectMultiScale(Image`2 image, Double scaleFactor, Int32 minNeighbors, Size minSize, Size maxSize)
       at WindowsFormsApplication1.Form1.button1_Click(Object sender, EventArgs e) in c:\users\moamen\documents\visual studio 2010\Projects\WindowsFormsApplication1\WindowsFormsApplication1\Form1.cs:line 44
       at System.Windows.Forms.Control.OnClick(EventArgs e)
       at System.Windows.Forms.Button.OnClick(EventArgs e)
       at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
       at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
       at System.Windows.Forms.Control.WndProc(Message& m)
       at System.Windows.Forms.ButtonBase.WndProc(Message& m)
       at System.Windows.Forms.Button.WndProc(Message& m)
       at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
       at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
       at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
       at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)
       at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(IntPtr dwComponentID, Int32 reason, Int32 pvLoopData)
       at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
       at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
       at System.Windows.Forms.Application.Run(Form mainForm)
       at WindowsFormsApplication1.Program.Main() in c:\users\moamen\documents\visual studio 2010\Projects\WindowsFormsApplication1\WindowsFormsApplication1\Program.cs:line 18
       at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
       at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
       at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
       at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean ignoreSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart()
  InnerException: 

提前致谢：）