Illumination structure for an interactive input system

1. A method for determining the location of at least one pointer in an interactive input system comprising:

capturing images generally across a display surface of a region of interest and a reflection of the region of interest;

examining the images to determine at least one real target location and at least one virtual target location for at least one pointer that is within the region of interest;

discarding infeasible combinations of the at least one real target location and the at least one virtual target location;

analyzing feasible combinations of the at least one real target location and the at least one virtual target location to resolve at least one true real target location and at least one true virtual target location associated with the at least one pointer by determining at least one pair comprising the at least one real target location and the at least one virtual target location associated with a reflection of the at least one real target location in a mirror; and

calculating a first real location for the at least one pointer corresponding to the at least one first true real target location and the at least one true virtual target location.

2. The method of claim 1 wherein the calculating is performed using triangulation.

3. An interactive input system comprising:

a region of interest associated with a display surface;

a mirror positioned with respect to the region of interest and producing a reflection thereof;

an imaging system capturing images of the region of interest and the reflection from different vantages; and

processing structure for examining the captured images to determine at least one real target location and at least one virtual target location for at least one pointer in the region of interest, discarding infeasible combinations of the at least one real target location and the at least one virtual target location, analyzing feasible combinations of the at least one real target location and the at least one virtual target location to resolve at least one real true target location and at least one true virtual location associated with the at least one pointer by determining at least one pair comprising the at least one real target location and the at least one virtual target location associated with a reflection of the at least one real target location in the mirror, and calculating a first real location for the at least one pointer corresponding to the at least one first true real target location and the at least one true virtual target location.

4. A non-transitory computer readable medium embodying a computer program for determining the location of at least one pointer in an interactive input system, the computer program comprising:

program code for capturing images generally across a display surface of a region of interest and a reflection of the region of interest;

program code for examining the images to determine at least one real target location and at least one virtual target location for at least one pointer that is within the region of interest;

program code for discarding infeasible combinations of the at least one real target location and the at least one virtual target location;

program code for analyzing feasible combinations of the at least one real target location and the at least one virtual target location to resolve at least one true real target location and at least one true virtual target location associated with the at least one pointer by determining at least one pair comprising the at least one real target location and the at least one virtual target location associated with a reflection of the at least one real target location in a mirror; and

program code for calculating a first real location for the at least one pointer corresponding to the at least one first true real target location and the at least one true virtual target location.

5. A method for determining the location of at least two pointers in an interactive input system comprising:

capturing images from different vantages of a region of interest and a reflection of the region of interest;

examining the images to identify a plurality of real target locations and a plurality of virtual target locations for at least two pointers in the region of interest;

discarding infeasible combinations of the plurality of real target locations and the plurality of virtual target locations;

analyzing feasible combinations of the plurality of real target locations and the plurality of virtual target locations to resolve a true real target location and a true virtual target location associated with each of the at least two pointers by determining a pair comprising one of the plurality of real target locations and one of the plurality of virtual target locations associated with a reflection of the at least one real target location in a mirror; and

calculating a real location for each of the at least two pointers associated with the corresponding true real target location and the corresponding true virtual location associated with the at least one true virtual target location.

6. The method of claim 5 comprising comparing the real location to the virtual location, and in response, determining location of the first of the at least two pointers.

7. An interactive input system comprising:

a region of interest associated with a display surface;

a mirror producing a reflection of the region of interest;

an imaging system capturing from different vantages images of the region of interest and the reflection; and

processing structure for examining the images to identify a plurality of real target locations and a plurality of virtual target locations for at least two pointers in the region of interest, discarding infeasible combinations of the plurality of real target locations and the plurality of virtual target locations, analyzing feasible combinations of the plurality of real target locations and the plurality of virtual target locations to resolve a true real target location and a true virtual target location associated with each of the at least two pointers by determining a pair comprising one of the plurality of real target locations and one of the plurality of virtual target locations associated with a reflection of the at least one real target location in a mirror, and calculating a real location for each of the at least two pointers associated with the corresponding true real target location and the corresponding true virtual location associated with the at least one true virtual target location.

8. A non-transitory computer readable medium embodying a computer program for determining a location of at least two pointers in an interactive input system, the computer program comprising:

program code for capturing images from different vantages of a region of interest and a reflection of the region of interest;

program code for examining the images to identify a plurality of real target locations and a plurality of virtual target locations for at least two pointers in the region of interest;

program code for discarding infeasible combinations of the plurality of real target locations and the plurality of virtual target locations;

program code for analyzing feasible combinations of the plurality of real target locations and the plurality of virtual target locations to resolve a true real target location and a true virtual target location associated with each of the at least two pointers by determining a pair comprising one of the plurality of real target locations and one of the plurality of virtual target locations associated with a reflection of the at least one real target location in a mirror; and

program code for calculating a real location for each of the at least two pointers associated with the corresponding true real target location and the corresponding true virtual location associated with the at least one true virtual target location.