This node creates a matte for the difference or motion between fields. Areas of difference appear white, enabling this node to be used as a mask within node trees. This is very useful for creating an advanced field blend that only blurs that areas that need to be blurred (ie the motion between fields) and retains the sharpness of the rest of the image. See the example, G Smater Deinterlace Blend.cfx, in ColorFX Node Trees.
