C# + emgucv显示实时视频并检测人脸

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

using System.Timers;
using System.Threading;
using Emgu.CV;
using Emgu.CV.Structure;
using Emgu.Util;

namespace FaceCapture
{
    public partial class MainWindows : Form
    {
        
        // variables
        private string haarXmlPath = "haarcascade_frontalface_alt_tree.xml";
        double scale = 1.5;
        // web camera
        private Capture capture;
        private bool capture_flag = true;
        private Image frame = null;
        Image gray = null;
        Image smallframe = null;
        
        private System.Timers.Timer capture_tick;

        public MainWindows()
        {
            InitializeComponent();

            capture_tick = new System.Timers.Timer();
            capture_tick.Interval = 100;
            capture_tick.Enabled = Enabled;
            capture_tick.Stop();
            capture_tick.Elapsed += new ElapsedEventHandler(CaptureProcess);
        }

        public void CaptureProcess(object sender, EventArgs arg)
        {
            frame = capture.QueryFrame();


            if (frame != null)
            {
                
                //face detection 

                //frame = frame.Flip(Emgu.CV.CvEnum.FLIP.HORIZONTAL);
                smallframe = frame.Resize(1 / scale, Emgu.CV.CvEnum.INTER.CV_INTER_LINEAR);//缩放摄像头拍到的大尺寸照片
                gray = smallframe.Convert(); //Convert it to Grayscale
                gray._EqualizeHist();//均衡化

                CascadeClassifier ccr = new CascadeClassifier(haarXmlPath);
                Rectangle[] rects = ccr.DetectMultiScale(gray, 1.3, 3, new Size(20, 20), Size.Empty);
                foreach (Rectangle r in rects)
                {
                    //This will focus in on the face from the haar results its not perfect but it will remove a majoriy
                    //of the background noise
                    Rectangle facesDetected = r;
                    facesDetected.X += (int)(facesDetected.Height * 0.6);
                    facesDetected.Y += (int)(facesDetected.Width * 0.8);
                    facesDetected.Height += (int)(facesDetected.Height * 0.1);
                    facesDetected.Width += (int)(facesDetected.Width * 0.2);

                    frame.Draw(facesDetected, new Bgr(Color.Red), 3);//绘制检测框
                }


                imageBox_capture.Image = frame;
            }
        }

       
        private void button_capture_start_Click(object sender, EventArgs e)
        {
            if (capture == null)
            {
                try
                {
                    capture = new Capture();
                }
                catch (NullReferenceException except)
                {
                    MessageBox.Show(except.Message);
                }
            }

            if (capture != null)
            {
                if (capture_flag)
                {
                    //Application.Idle += new EventHandler(CaptureProcess);
                    capture_tick.Start();
                    button_capture_start.Text = "停止";
                }
                else
                {
                    //Application.Idle -= new EventHandler(CaptureProcess);
                    capture_tick.Stop();
                    button_capture_start.Text = "开始";
                }
                capture_flag = !capture_flag;
            }
        }

        private void button_capture_frame_Click(object sender, EventArgs e)
        {
           
            face_box.Image = this.frame;
            
        }
    }
}