What does diffusion mean and what is a diffused surface or diffuser?
Diffused reflection is light that reflects in multiple directions off an uneven surface. A diffused surface is the surface that the light is reflecting off of. In multi-touch tables it can be used in a number of ways: • In a projector based setup, the projection surface is sometimes called the diffuser, because it stops a lot of the projected image’s light. • In an LCD based setup, a diffuser is needed to go under the LCD screen so that the back light can evenly cover the screen. Common materials used are vellum, tracing paper, or one of the diffusion layers from the back light. • In a Rear Diffused Illumination (Rear DI) setup, a diffuser is placed on the touch surface (often the projection layer), IR light is projected out through the touch surface and when it hits your finger, is reflected back to the camera. The camera sees the diffused light off your finger as being brighter and thus makes a blob out of it. • In a Front Diffused Illumination (Front DI) setup, a diffuser is placed
