Motion detect optimize.

[Pirelli72]

Hi, from my cam I analyze each frame to detect the movements. The code I wrote works fine but I can only analyze 6 / 7 frames per second.
I tried using a loop Parallel.For to exploit multi-core but I have not had many advantages. ow can I improve my code?

 Private fronte As Boolean
    Private rgbValues_old() As Byte
    Private Function ControlImageBiZoneThread(ByVal immagine As Image) As Boolean
        Try
            Dim esito As Boolean
            Dim bmp As New Bitmap(immagine)
            Dim bitmap As System.Drawing.Imaging.BitmapData
            Dim rect As Rectangle
            Dim ptr As IntPtr
            Dim bytes As Integer
            Dim pixelBytes As Integer = 3
            Dim rgbValues_new() As Byte
            Dim rgbValues_tmp() As Byte

            rect = New Rectangle(0, 0, bmp.Width, bmp.Height)
            bitmap = bmp.LockBits(rect, Drawing.Imaging.ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb)

            ' Get the address of the first line.
            ptr = bitmap.Scan0

            ' This code is specific to a bitmap with 24 bits per pixels.
            bytes = bmp.Width * bmp.Height * 3

            ReDim rgbValues_new(bytes - 1)
            ReDim Preserve rgbValues_old(bytes - 1)
            ReDim rgbValues_tmp(bytes - 1)

            ' Copy the RGB values into the array.
            System.Runtime.InteropServices.Marshal.Copy(ptr, rgbValues_new, 0, bytes)

            rgbValues_tmp = DirectCast(rgbValues_new.Clone, Byte())

            If fronte = False Then GoTo salta


            Dim changedX(bmp.Width - 1, bmp.Height - 1) As Integer
            Dim scanPixel As Integer
            Dim lumaPixel As Double
            Dim Max As Double
            Dim Min As Double
            Dim temp As Integer
            Dim listaPointX As New List(Of Integer)
            Dim listaPointY As New List(Of Integer)

            PixelChanged = 0
            scanPixel = 0
            Dim PixelChanged2 As Integer


            '*********************************************************************************
            Parallel.For(0, bmp.Height - 1, Sub(Y)
                                                For X As Integer = 0 To 639
                                                    Dim pos As Integer = (Y * bitmap.Stride) + (X * pixelBytes)

                                                    scanPixel += 1

                                                    'Calcolo luminosità
                                                    lumaPixel = rgbValues_new(pos) / 255
                                                    Max = 0
                                                    Min = 1
                                                    If lumaPixel > Max Then Max = lumaPixel
                                                    If lumaPixel < Min Then Min = lumaPixel
                                                    'temp += System.Math.Min(((Max + Min) / 2 * 255), 255)
                                                    System.Threading.Interlocked.Add(temp, CInt(System.Math.Min(((Max + Min) / 2 * 255), 255)))


                                                    If (rgbValues_new(pos) >= SensibiltàColoriView.B AndAlso System.Math.Abs(CInt(rgbValues_new(pos)) - CInt(rgbValues_old(pos))) > SensibilitaColore) Then
                                                        System.Threading.Interlocked.Add(PixelChanged2, CInt(1 + ((480 - Y) * (pesoPixel / 480))))

                                                        listaPointX.Add(X)
                                                        listaPointY.Add(Y)

                                                        If _showPixelChanged Then
                                                            rgbValues_new(pos + 2) = PixelChangedColor.R    'Red
                                                            rgbValues_new(pos + 1) = PixelChangedColor.G    'Green
                                                            rgbValues_new(pos) = PixelChangedColor.B        'Blue
                                                        End If
                                                        If esito = False AndAlso PixelChanged2 > SensilitàPixel Then esito = True : Exit For
                                                    End If
                                                Next
                                            End Sub)
            '*********************************************************************************

            luminosity = temp / scanPixel
            listaPointX.Sort()
            listaPointY.Sort()

            System.Runtime.InteropServices.Marshal.Copy(rgbValues_new, 0, ptr, bytes)
            bmp.UnlockBits(bitmap)

            Dim myPoint(1) As Point
            If listaPointX.Count > 0 Then myPoint(0).X = listaPointX(0)
            If listaPointY.Count > 0 Then myPoint(0).Y = listaPointY(0)
            If listaPointX.Count > 0 Then myPoint(1).X = listaPointX(listaPointX.Count - 1)
            If listaPointY.Count > 0 Then myPoint(1).Y = listaPointY(listaPointY.Count - 1)

            RaiseEvent PixelChangedViewControllo(bmp, bmp, esito, PixelChanged2, luminosity, myPoint)

salta:      rgbValues_old = DirectCast(rgbValues_tmp.Clone, Byte())
            fronte = True

            bmp.Dispose()
            bmp = Nothing
            rect = Nothing
            listaPointX = Nothing
            listaPointY = Nothing

            Return esito

        Catch ex As Exception
            'MsgBox(ex.Message)
        End Try
    End Function

 Public Sub DoControl()
        Try
            myTask = New System.Threading.Thread(AddressOf DoControltask)
            myTask.IsBackground = True
            myTask.Priority = System.Threading.ThreadPriority.Highest
            myTask.SetApartmentState(Threading.ApartmentState.STA)
            myTask.Start()
        Catch ex As Exception
        End Try
    End Sub

    Private Sub DoControltask()
        Do While _StartStopElaboration
            Try
                countF += 1
                SendMessage(hHwndFinestra, WM_CAP_EDIT_COPY, 0, 0)
                System.Threading.Thread.Sleep(threadSlep)
                If System.Environment.TickCount - tempElapsed >= 1000 Then
                    tempElapsed = System.Environment.TickCount
                    countFrame = countF
                    countF = 0
                End If
                RaiseEvent EsitoControllo(ControlImageBiZoneThread(My.Computer.Clipboard.GetImage), PixelChanged, countFrame)
            Catch ex As Exception
                MsgBox(ex.Message)
            End Try
        Loop
    End Sub

Thanks.