vb.net - draw rectangle filled with white noise on a image

Question

I use following code to draw a rectangle on a image:

 Dim gr As Graphics = Graphics.FromImage(augImage)
 Dim rect As New Rectangle(xposLabel, yposLabel, w, h)
 gr.FillRectangle(Brushes.White, rect)

now, I would need this rectangle to be filled with white noise. How can this be done?