A touch system comprises a touch surface and at least one camera acquiring
images of the touch surface. A pointer contact data generator generates
pointer position data in response to pointer contact with the touch
surface, the pointer position data representing where on the touch
surface pointer contact is made. A processor communicates with the at
least one camera and the pointer contact data generator. The processor
analyzes acquired images to determine the type of pointer used to contact
the touch surface, and processes the pointer position data in accordance
with the determined type of pointer. In the preferred embodiment the
processor distinguishes between pointer tip touch surface contacts,
pointer backend touch surface contacts and finger touch surface contacts.
A writing function is invoked in response to pointer tip touch surface
contacts. An erase function is invoked in response to pointer backend
touch surface contacts. Mouse events are generated in response to finger
touch surface contacts.