Instrument Detection with an Optical Touch Sensitive Device, with Associating Contacts with Active Instruments

A non-transitory computer-readable medium comprising computer program instructions that when executed by a processor of a touch-sensitive device causes the processor to perform steps comprising:

• receiving information specific to each of one or more detected touch events;
• receiving information specific to an active instrument;
• analyzing the information specific to the active instrument with the information specific to the detected touch events for consistency with a situation in which the active instrument caused one of the detected touch events;
• and
• making an association between the active instrument and one of the detected touch events based on said analysis.

An optical touch-sensitive device comprising:

• a surface for which one or more touch events are to be detected;
• a detector configured to detect the one or more touch events;
• and
• a touch event processor coupled, directly or indirectly, to the detector, the touch event processor configured to perform steps comprising:
• receiving information specific to each of the one or more detected touch events,
• receiving information specific to an active instrument,
• analyzing the information specific to the active instrument with the information specific to the detected touch events for consistency with a situation in which the active instrument caused one of the detected touch events, and
• making an association between the active instrument and one of the detected touch events based on said analysis.