Windows Forms: Webcam Face Detection for .NET using EMGU.CV in C#

Creating a new Windows Forms Application project, then open your form designer.

Dragging Label, Combobox, PictureBox and Button controls from your Visual Studio Toolbox to your form designer.

After you finish your form design, you need to right-click on your project, then select Manage Nuget Packages.

Face detection and recognition using emgu, opencv and c#

Next, Search and Install 'AForge'. 'Emgu' to your project.

Declare two variables as shown below.

FilterInfoCollection filter;
VideoCaptureDevice device;

Adding a Form_Load event handler that allows you to detect your webcam name, then add the device name to the Combobox control.

private void Form1_Load(object sender, EventArgs e)
{
    filter = new FilterInfoCollection(FilterCategory.VideoInputDevice);
    foreach (FilterInfo device in filter)
        cboDevice.Items.Add(device.Name);
    cboDevice.SelectedIndex = 0;
    device = new VideoCaptureDevice();
}

You need to download haarcascade_frontalface_alt_tree.xml from github website, then create a cascadeClassifier variable.

This is a training data file helps you detect faces in image.

static readonly CascadeClassifier cascadeClassifier = new CascadeClassifier("haarcascade_frontalface_alt_tree.xml");

Adding a click event handler to the Detect button allows you to capture image from the webcam.

private void btnDetect_Click(object sender, EventArgs e)
{
    device = new VideoCaptureDevice(filter[cboDevice.SelectedIndex].MonikerString);
    device.NewFrame += Device_NewFrame;
    device.Start();
}

You should implement NewFrame event handler allows you to detect face from webcam.

private void Device_NewFrame(object sender, NewFrameEventArgs eventArgs)
{
    Bitmap bitmap = (Bitmap)eventArgs.Frame.Clone();
    Image<Bgr, byte> grayImage = new Image<Bgr, byte>(bitmap);
    Rectangle[] rectangles = cascadeClassifier.DetectMultiScale(grayImage, 1.2, 1);
    foreach (Rectangle rectangle in rectangles)
    {
        using (Graphics graphics = Graphics.FromImage(bitmap))
        {
            using (Pen pen = new Pen(Color.Red, 1))
            {
                graphics.DrawRectangle(pen, rectangle);
            }
        }
    }
    pic.Image = bitmap;
}

You can also draw squares on faces that you detect.

And don't forget to close your webcam when closing your form.

private void Form1_FormClosing(object sender, FormClosingEventArgs e)
{
    if (device.IsRunning)
        device.Stop();
}

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