Method for controlling illumination employed by a computer pointing peripheral and computer pointing peripheral

1 . A method of operating a computer pointing peripheral, comprising:

capturing images of a support surface to perform navigational analysis to generate data indicative of movement of said computer pointing peripheral for output to a computer system;

analyzing at least one image characteristic;

modifying an image exposure time in response to said analyzing; and

modifying an intensity of illumination of said support surface when said image exposure time fails to satisfy an operating parameter.

2 . The method of claim 1 wherein said modifying an intensity of illumination comprises:

modifying a drive current provided to an illumination device used to illuminate said support surface.

3 . The method of claim 2 wherein said illumination device is a coherent light source.

4 . The method of claim 2 wherein said illumination device is a highly directional light source.

5 . The method of claim 1 wherein said analyzing at least one image characteristic determines whether an average pixel value is above a threshold value.

6 . The method of claim 1 wherein said analyzing at least one image characteristic determines whether a maximum pixel value is above a threshold value.

7 . The method of claim 1 wherein said modifying an exposure time modifies a shutter operation according to a number of clock cycles.

8 . The method of claim 7 further comprising:

determining whether said number of clock cycles is within a predetermined range.

9 . A computer pointing peripheral, comprising:

an illumination element for illuminating a support surface;

an imaging array for capturing images of said support surface;

logic for processing said images to generate output signals that are indicative of movement of said computer pointing peripheral;

logic for analyzing said images for at least one characteristic;

logic for modifying an image exposure time of said imaging array, wherein said logic for modifying is responsive to said logic for analyzing; and

logic for modifying an intensity of illumination provided by said illumination element when said image exposure time fails to satisfy an operating parameter.

10 . The computer pointing peripheral of claim 9 wherein said logic for modifying an intensity of illumination controls a drive current provided to said illumination element.

11 . The computer pointing peripheral of claim 9 wherein said illumination element is a coherent light source.

12 . The computer pointing peripheral of claim 9 wherein said illumination element is a highly directional light source.

13 . The computer pointing peripheral of claim 9 wherein said at least one image characteristic is a parameter defining a threshold average pixel value.

14 . The computer pointing peripheral of claim 9 wherein said at least one image characteristic is a parameter defining a maximum pixel value.

15 . The computer pointing peripheral of claim 9 further comprising:

logic for generating a control signal to operate a shutter according to a number of clock signals, wherein said logic for generating operates in response to said logic for modifying an image exposure time.

16 . The computer pointing peripheral of claim 15 wherein said logic for modifying an image exposure time determines whether said number of clock cycles is within a predetermined range.

17 . A computer pointing peripheral, comprising:

means for illuminating a support surface;

means for capturing images of said support surface;

means for processing said images to generate output signals that are indicative of movement of said computer pointing peripheral;

means for analyzing said images for at least one characteristic;

means for modifying an image exposure time of said imaging array according to said at least one characteristic; and

means for modifying an intensity of illumination provided by said means for illuminating when said image exposure time fails to satisfy an operating parameter.

18 . The computer pointing peripheral of claim 17 wherein said means for analyzing determines whether an average pixel value fails to satisfy a predefined value.

19 . The computer pointing peripheral of claim 17 wherein said means for analyzing determines whether a maximum pixel value fails to satisfy a predefined value.

20 . The computer pointing peripheral of claim 17 wherein said means for modifying an intensity of illumination determines whether said image exposure time falls within a predetermined range.