Cam Alarm 2.0 - Alarm system run from a web camera

// Motion Detector
//
// Copyright � Andrew Kirillov, 2005
// andrew.kirillov@gmail.com
//
namespace CamAlarm
{
	using System;
	using System.Drawing;
	using System.Threading;

	/// <summary>
	/// Camera class
	/// </summary>
	public class Camera
	{
		private IVideoSource	videoSource = null;
		private IMotionDetector	motionDetector = null;
		private Bitmap			lastFrame = null;

		// image width and height
		private int		width = -1, height = -1;

		// alarm level
		private double	alarmLevel = 0.005;

		//
		public event EventHandler	NewFrame;
		public event EventHandler	Alarm;

		// LastFrame property
		public Bitmap LastFrame
		{
			get { return lastFrame; }
		}
        public double AlarmLevel
        {
            get { return alarmLevel; }
            set { alarmLevel = value; }
        }
		// Width property
		public int Width
		{
			get { return width; }
		}
		// Height property
		public int Height
		{
			get { return height; }
		}
		// FramesReceived property
		public int FramesReceived
		{
			get { return ( videoSource == null ) ? 0 : videoSource.FramesReceived; }
		}
		// BytesReceived property
		public int BytesReceived
		{
			get { return ( videoSource == null ) ? 0 : videoSource.BytesReceived; }
		}
		// Running property
		public bool Running
		{
			get { return ( videoSource == null ) ? false : videoSource.Running; }
		}
		// MotionDetector property
		public IMotionDetector MotionDetector
		{
			get { return motionDetector; }
			set { motionDetector = value; }
		}

		// Constructor
		public Camera( IVideoSource source ) : this( source, null )
		{ }
		public Camera( IVideoSource source, IMotionDetector detector )
		{
			this.videoSource = source;
			this.motionDetector = detector;
			videoSource.NewFrame += new CameraEventHandler( video_NewFrame );
		}

		// Start video source
		public void Start( )
		{
			if ( videoSource != null )
			{
				videoSource.Start( );
			}
		}

		// Siganl video source to stop
		public void SignalToStop( )
		{
			if ( videoSource != null )
			{
				videoSource.SignalToStop( );
			}
		}

		// Wait video source for stop
		public void WaitForStop( )
		{
			// lock
			Monitor.Enter( this );

			if ( videoSource != null )
			{
				videoSource.WaitForStop( );
			}
			// unlock
			Monitor.Exit( this );
		}

		// Abort camera
		public void Stop( )
		{
			// lock
			Monitor.Enter( this );

			if ( videoSource != null )
			{
				videoSource.Stop( );
			}
			// unlock
			Monitor.Exit( this );
		}

		// Lock it -ju changed from Enter to TryEnter
		public void Lock( )
		{
			Monitor.TryEnter( this, 5000 );
		}

		// Unlock it
		public void Unlock( )
		{
			Monitor.Exit( this );
		}

		// On new frame
		private void video_NewFrame( object sender, CameraEventArgs e )
		{
			try
			{
				// lock
				Monitor.Enter( this );

				// dispose old frame
				if ( lastFrame != null )
				{
					lastFrame.Dispose( );
				}

				lastFrame = (Bitmap) e.Bitmap.Clone( );

				// apply motion detector
				if ( motionDetector != null )
				{
					motionDetector.ProcessFrame( ref lastFrame );

					// check motion level
					if ((motionDetector.MotionLevel >= alarmLevel) && (Alarm != null))
					{
						Alarm(this, new EventArgs());
					}
				}

				// image dimension
				width = lastFrame.Width;
				height = lastFrame.Height;
			}
			catch ( Exception )
			{
			}
			finally
			{
				// unlock
				Monitor.Exit( this );
			}

			// notify client
			if ( NewFrame != null )
				NewFrame( this, new EventArgs( ) );
		}
	}
}