Passive touch system and method of detecting user input

A multiple camera tracking system for interfacing with an application program running on a computer, the tracking system comprising:

• two or more video cameras arranged to provide different viewpoints of a region of interest and operable to produce a series of video images;
• a processor operable to receive the series of video images and detect objects appearing in the region of interest, the processor executing a process to:
• generate a background data set from the video images;
• generate an image data set for each received video image;
• compare each image data set to the background data set to produce a difference map for each image data set;
• detect a relative position of an object of interest within each difference map;
• and
• produce an absolute position of the object of interest from the relative positions of the object of interest and map the absolute position to a position indicator associated with the application program.

A multiple camera tracking system for interfacing with an application program running on a computer, the tracking system comprising:

• two or more video cameras arranged to provide different viewpoints of a region of interest and operable to produce a series of video images;
• a processor operable to receive the series of video images and detect objects appearing in the region of interest, the processor executing a process to:
• generate a background data set from the video images;
• generate an image data set for each received video image;
• compare each image data set to the background data set to produce a difference map for each image data set;
• detect a relative position of an object of interest within each difference map;
• produce an absolute position of the object of interest from the relative positions of the object of interest;
• define sub regions within the region of interest;
• identify a sub region occupied by the object of interest;
• associate an action with the identified sub region that is activated when the object of interest occupies the identified sub region;
• and
• apply the action to interface with the application program.