I don't know how to thank you Bill. You made my life much easier!! I will try it ASAP and let you know. Soheil -- View this message in context: http://itk-insight-users.2283740.n2.nabble.com/Pixel-difference-between-two-images-tp6832343p6883001.html Sent from the ITK Insight Users mailing list archive at Nabble.com.