Position determination utilizing a cordless device

A method for generating position information, the method comprising:

• illuminating a retroreflector that is integrated into a pointing device;
• generating a first set of image data and a second set of image data, wherein the first set of image data includes a stronger indication of the reflector than the second set of image data;
• and
• generating position information related to the reflector using the first set of image data and the second set of image data, wherein generating position information comprises taking the difference between the first set of image data and the second set of image data, wherein taking the difference between the first set of image data and the second set of image data comprises taking the difference between corresponding data points of the first and second sets of image data such that most of the corresponding data points from the first and second sets of image data cancel each other out except for data points that correspond to the retroreflector.

A system for generating position information, the system comprising:

• a pointing device comprising a retroreflector;
• means for generating on-axis image data and off-axis image data;
• and
• a processor configured to generate position information related to the pointing device from the on-axis image data and the off-axis image data, wherein the processor is configured to find the difference between the on-axis image data and off-axis image data, wherein taking the difference between the first set of image data and the second set of image data comprises taking the difference between corresponding data points of the first and second sets of image data such that most of the corresponding data points from the first and second sets of image data cancel each other out except for data points that correspond to the retroreflector.

A method for generating position information, the method comprising:

• illuminating a retroreflector that is integrated into a pointing device;
• generating on-axis image data in response to the illumination;
• generating off-axis image data in response to the illumination;
• and
• generating position information related to the retroreflector from the on-axis image data and the off-axis image data, wherein generating position information comprises taking the difference between the on-axis and off-axis image data, wherein taking the difference between the on-axis image data and the off-axis image data comprises taking the difference between corresponding data points of the on-axis and off-axis image data which results in a difference image such that most of the corresponding data points from the on-axis and off-axis image data cancel each other out in the difference image except for data points that correspond to the retroreflector.