Problem with EigenObjectRecognizer

See more:

C#

recognition

Emgu-CV

I've tried to code a face recognition program and need some help from the community. The code posted below compiled with no error and the recognizer working if the threshold that i set is 0, if i set the threshold > 0 its display Unknown Face definitely.
I am using 4 training image for a person.
Face in Database :
PersonA:
- PersonA1, PersonA2, PersonA3, PersonA4
PersonB:
- PersonB1, PersonB2, PersonB3, PersonB4
Scenario Example:
If new person (none in database) face detected lets called PersonC, but the program always display name from database between PersonA or PersonB.

How to display new detected face / PersonC as Unknown Face if there are no face in database. Any idea on where have i gone wrong? Thanks in advance.

I'm using emgu cv 2.2.1.1150 with c# 2010 express
imgRecognizer Initialization:

private void AttendanceForm_Load(object sender, EventArgs e)
{
    dbFA = new FRAttendance_DBDataContext();
    timer.Start();
    face = new HaarCascade("haarcascade_frontalface_alt_tree.xml");
    Scanner = new Capture();
    Scanner.QueryFrame();
    Application.Idle += new EventHandler(StartCamera);
    try
    {
    LoadData();
    ImageToList();
    MCvTermCriteria termCrit = new MCvTermCriteria(rowCount, 0.001);
    imgRecognizer = new EigenObjectRecognizer(trainingImages.ToArray(), personsLabel.ToArray(), 1000, ref termCrit);
    }
    catch (Exception err)
    {
        MessageBox.Show(err.ToString());
    }
}

Recognizer Function :

private void btnScan_Click(object sender, EventArgs e)
{
    if (trainingImages.ToArray() != null)
    {
        try
        {
            faceImgLabel = imgRecognizer.Recognize(result);
            if (faceImgLabel.Trim().Equals(""))
            {
                txtHSID.Text = "Unknown";
                txtHSName.Text = "Unknown";
                MessageBox.Show("Unknown Face", "Information", MessageBoxButtons.OK, MessageBoxIcon.Warning);
            }
            else
            {
                logMeIn(faceImgLabel);
            }
        }
        catch(Exception errScan)
        {
            MessageBox.Show(errScan.ToString());
            MessageBox.Show("Wait until face detected", "Information", MessageBoxButtons.OK, MessageBoxIcon.Information);
        }
    }
    else
        MessageBox.Show("No image in collection list", " Information ", MessageBoxButtons.OK, MessageBoxIcon.Information);
        imgScan.Image = result;
}