image contrast in vb.net

http://stackoverflow.com/questions/3115076/adjust-the-contrast-of-an-image-in-c-sharp-efficiently[^]



solution for above question is not working in vb 2005

i need solution in vb2005
below is vb2005 code

Public Shared Function AdjustContrast(Image As Bitmap, Value As Single) As Bitmap
    Value = (100F + Value) / 100F
    Value *= Value
    Dim NewBitmap As Bitmap = DirectCast(Image.Clone(), Bitmap)
    Dim data As BitmapData = NewBitmap.LockBits(New Rectangle(0, 0, NewBitmap.Width, NewBitmap.Height), ImageLockMode.ReadWrite, NewBitmap.PixelFormat)

    For y As Integer = 0 To NewBitmap.Height - 1
        Dim row As Pointer(Of Byte) = CType(data.Scan0, Pointer(Of Byte)) + (y * data.Stride)
        Dim columnOffset As Integer = 0
        For x As Integer = 0 To NewBitmap.Width - 1
            Dim B As Byte = row(columnOffset)
            Dim G As Byte = row(columnOffset + 1)
            Dim R As Byte = row(columnOffset + 2)

            Dim Red As Single = R / 255F
            Dim Green As Single = G / 255F
            Dim Blue As Single = B / 255F
            Red = (((Red - 0.5F) * Value) + 0.5F) * 255F
            Green = (((Green - 0.5F) * Value) + 0.5F) * 255F
            Blue = (((Blue - 0.5F) * Value) + 0.5F) * 255F

            Dim iR As Integer = CInt(Red)
            iR = If(iR > 255, 255, iR)
            iR = If(iR < 0, 0, iR)
            Dim iG As Integer = CInt(Green)
            iG = If(iG > 255, 255, iG)
            iG = If(iG < 0, 0, iG)
            Dim iB As Integer = CInt(Blue)
            iB = If(iB > 255, 255, iB)
            iB = If(iB < 0, 0, iB)

            row(columnOffset) = CByte(iB)
            row(columnOffset + 1) = CByte(iG)
            row(columnOffset + 2) = CByte(iR)

            columnOffset += 4
        Next
    Next

    NewBitmap.UnlockBits(data)

    Return NewBitmap
End Function

pointer(of byte) gives error

pls help

Tags: Visual Basic (Visual Basic 8 (2005)), Visual Studio (Visual Studio 2005), Image