A MULTI-TOUCH THREE DIMENSIONAL TOUCH-SENSITIVE TABLET

A prototype touch-sensitive tablet Is presented. The tablet's main innovation is that It Is capable of sensing mare than one point of contact at a time. In addition to being able to provide position coordinates, the tablet also gives a measure of degree of contact, independently for each point of contact. In order to enable mutUtouch sensing, the tablet surface is divided Into a gdd of dlacrefe points. The points are scanned using a recursive area subdivision algorithm. In order to minimize the resolution lost due to the discrete nature of the grid, a novel interpolation scheme has been developed. Finally, the paper briefly discusses how multi-touch sensing, interpolation, and degree of contact sensing can be combined to expand our vocabulary In human-computer Interaction.