MULTIPLE POINTER AMBIGUITY AND OCCLUSION RESOLUTION

1 . A method of resolving ambiguities between at least two pointers in an interactive input system comprising:

capturing images of a region of interest;

processing image data to determine a plurality of potential targets for said at least two pointers within the region of interest and a current target location for each potential target, said plurality of potential targets comprising real and phantom targets;

tracking each potential target within said region of interest and calculating a predicted target location for each potential target; and

determining a pointer path associated at least with each real target.

2 . The method of claim 1 , wherein said tracking is performed using a predictive filter.

3 . The method of claim 2 , wherein the predictive filter is utilized to determine and correct each pointer path.

4 . A method of resolving ambiguities between pointers in an interactive input system when at least one pointer is brought into a region of interest where at least one pointer already exists therein, the method comprising:

determining real and phantom targets associated with each pointer;

setting a real error function associated with said real targets;

setting a phantom error function associated with said phantom targets, wherein said phantom error function is set to a value different from said real error function; and

tracking and resolving each pointer based on their associated error functions.

5 . The method of claim 4 further comprising comparing said real error function to said phantom error function to determine a pointer path for each target.

6 . The method of claim 5 , wherein if the real error function exceeds the phantom error function, the pointer path is corrected to correspond to a pointer path associated with the phantom target.

7 . A method of resolving ambiguities between pointers in an interactive input system when at least two pointers are brought into a region of interest simultaneously:

determining real and phantom targets associated with each pointer contact;

setting error functions associated with each target; and

tracking and resolving each pointer contact through their associated error functions.

8 . An interactive input system comprising:

at least two imaging devices having at least partially overlapping fields of view encompassing a region of interest; and

processing structure processing image data acquired by the imaging devices to track the position of at least two pointers within said region of interest and resolve ambiguities between the pointers.

9 . The interactive input system of claim 8 , wherein said processing structure comprises a target birth module for determining targets for said at least two pointers.

10 . The interactive input system of claim 9 , wherein said processing structure further comprises a target tracking module for tracking said targets in said region of interest.

11 . The interactive input system of claim 10 , wherein said processing structure further comprises a state estimation module for determining locations of said at least two pointers based on information from said target birth module, said target tracking module, and image data from said at least two imaging devices.

12 . The interactive input system of claim 11 , wherein said processing structure further comprises a blind tracking module for, when one of the at least two pointers becomes obscured for a prolonged period, determining a location for said obscured one of the at least two pointers.