EMGUCV facial recognition issue in VB.NET - vb.net

Question

I'm trying to implement a web app with VB.NET which is supposed to perform facial recognition on images in a folder using EMGUCV library. Anyway, when I call method train on the facerecognizer object a strange exception is raised:
'OpenCV: 0 <= _rowRange.start && _rowRange.start <= _rowRange.end && _rowRange.end <= m.rows
Here's my test code:
Imports System.Drawing
Imports Emgu.CV
Imports Emgu.CV.Face
Imports Emgu.CV.Structure
Imports Emgu.CV.Util
Public Class _Default
Inherits Page
Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
End Sub
Protected Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim images As New Mat
Dim Palb0 = "c://IMGDB//Alberto//0.jpg"
Dim Palb1 = "c://IMGDB//Alberto//1.jpg"
Dim Pcon0 = "c://IMGCONFRONTO//0.jpg"
images.PushBack(CvInvoke.Imread(Palb0, CvEnum.LoadImageType.Grayscale))
images.PushBack(CvInvoke.Imread(Palb1, CvEnum.LoadImageType.Grayscale))
Dim model = New EigenFaceRecognizer(80, Double.PositiveInfinity)
Dim labels As New VectorOfInt
Dim a(0) As Integer
a(0) = 0
labels.Push(a)
model.Train(images, labels)
Dim imgConf As Mat
imgConf = CvInvoke.Imread(Pcon0, CvEnum.LoadImageType.Grayscale)
model.Predict(imgConf)
Dim PR As FaceRecognizer.PredictionResult
Dim dst = PR.Distance
Dim lbl = PR.Label
MsgBox(dst)
End Sub
End Class
I tryed nearly everything but can' solve it. Any help will be really appreciated.

Answer 1

I managed to find a solution myself.
The roblem was really as simpe as the type of object I used for the constructor. It was supposed to be a VectorOfMat instead of Mat. the class couldn't work because it expected an array.
Dim images As New VectorOfMat
Another problem was in the constructor itself. It was supposed to be:
Dim model As New EigenFaceRecognizer(80, Double.PositiveInfinity)
One more piece of advice: If the train method doesen't receive an array of mat of at least two images, it will throw another exception. The images are supposed to be of the same size or (strange) the object will throw one more exception.
Finally the correct code for the predictionresult is:
Dim PR As FaceRecognizer.PredictionResult = model.Predict(imgConf)
and you get eigenfaces prediction distance:
Dim dis = PR.Distance
Hope this can get somebody out of trouble.
Ceers.