如何将帧馈入运动检测器对象AForge.net？

Question

I'm trying to get a simple motion detection program working using the AForge.net framework. On the AForge website is an example of such a program, but it's quite vague:

    // create motion detector
MotionDetector detector = new MotionDetector(
    new SimpleBackgroundModelingDetector( ),
    new MotionAreaHighlighting( ) );

// continuously feed video frames to motion detector
while ( ... )
{
    // process new video frame and check motion level
    if ( detector.ProcessFrame( videoFrame ) > 0.02 )
    {
        // ring alarm or do something else
    }
}

I need some help with the condition for the while loop, as I can't find a solution for how to feed video frames into the MotionDetector object.

Thanks.

Answer 1

You'll want to take advantage of AForge's DirectShow VideoInputDevice. And instead of a while loop you will have a NewFrame event to control the motion detector.

First you'll need the references:

using AForge.Video.DirectShow;
using AForge.Video;
using AForge.Vision.Motion;
using System.Drawing;

Next you will need to get your capture device eg your webcam and add a new frame event handler to the NewFrame event for the device:

Cameras = new FilterInfoCollection(FilterCategory.VideoInputDevice);
VideoCaptureDevice Camera = new VideoCaptureDevice(Cameras[0].MonikerString);
Camera.NewFrame += new NewFrameEventHandler(ProcessNewFrame);

Now you can implement the NewFrameEventHandler however you choose:

private void ProcessNewFrame(object sender, NewFrameEventArgs eventArgs)
{
    Bitmap frame = (Bitmap) eventArgs.Frame.Clone();
    if (detector.ProcessFrame(frame) > 0.02)
    {
        // ring alarm or do somethng else
    }
}