Imaging compensation method for optical pointing devices

• US 6,631,303 B1
• Filed: 03/24/2000
• Issued: 10/07/2003
• Est. Priority Date: 03/24/2000
• Status: Expired due to Term

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Albulet, Mihai, de Leon, Ceasar B.
• Primary Examiner(s): PATEL, RAMESH B
• Application Number:
  US09/533,801
• Time in Patent Office: 1,292 Days
• Field of Search: 700/83, 700/84, 700/17, 700/85, 700/86, 700/59, 345/158-159, 345/163-166, 345/156-157, 345/167
• US Class Current: 700/85
• CPC Class Codes: G06F 3/0312 for tracking the rotation of a spherical or circular member, e.g. optical rotary encoders used in mice or trackballs using a tracking ball or in mouse scroll wheels tracking relative movement in co-operation with a regularly or irregularly patterned surface, e.g. as in optical mice G06F3/0317; constructional details of scroll or thumb-wheels G06F3/0362; optical rotary encoders G01D5/3473
• CPC Class Codes: G06F 3/038 Control and interface arrangements therefor, e.g. drivers or device-embedded control circuitry

Abstract

An imaging compensation or transformation method for signals detected by a sensor which is placed arbitrarily away from its ideal location into signals which would result if the sensor were in the ideal location. This method links movement of the on-screen cursor to the movement of the ball by a user. The actual location of the sensor in the device can be at any necessary location relative to the other components of the device within the housing, and the necessary transformation functions can be calculated and applied to the signals. Enabling placement of the sensor at a location which is displaced from the ideal location provides degrees of design freedom to optimize ergonomic and aesthetic factors. The compensation or conversion method is a transformation which simulates the sensor being disposed at the ideal location regardless of where it is actually placed. This is done by defining a user vector space, a sensor vector space and a reported vector space. The actuation of the ball occurs in the user vector space which corresponds a detected movement in the sensor vector space. The motion detected in the sensor vector space is transformed to movement in the reported vector space which simulates the movement of the ball as if the sensor were located in the ideal location.

Claims

1. A method for providing signals from a computer input device having a ball adapted to be rotationally manipulated by a user in a user vector space to a host PC, said method comprising:

providing a microcontroller coupled to a sensor positioned at a first location parallel to a plane tangent to the ball, the sensor disposed in a sensor vector space;

detecting rotational movement of the ball by the sensor and producing a detected vector motion report correlating to the rotational position of the ball;

converting the detected vector report into a reported vector report which simulates a detected vector report that would be produced by a sensor positioned at a second location parallel to another plane tangent to the ball, the reported vector report disposed in a reported vector space; and

processing the reported vector report into input signals to the host PC to correlate movement of the ball to movement of an on-screen cursor.

2. The method of claim 1, wherein the step of converting includes the step of mapping vectors from a user vector space to a sensor vector space.

3. The method of claim 2, wherein the step of converting includes the step of mapping vectors from a sensor space to a reported space.

4. The method of claim 1, wherein the step of converting the detected vector report into a reported vector report is accomplished by comparing detected vector reports to corresponding reported vector reports in a table.

5. The method of claim 1, wherein the step of converting the detected vector report into a reported vector report includes error correction to eliminate at least one round-off error necessitated by employing the table of values.

6. The method of claim 1, wherein the second location is diametrically opposed to an ideal user contact point such that said converting accounts for angular displacement of the sensor away from the second location.

7. A method of transforming a signal detected by a sensor in a first sensor location to an input signal for a monitor which simulates a signal detected by a sensor in a second sensor location, said method comprising the steps of:

receiving detected signals at the first sensor location correlating to movement of a pattern relative to the sensor;

processing the detected signals by applying transformation equations to simulate corresponding signals that would be detected by a sensor in a second location; and

processing the transformed signals into an input signal for a monitor to correlate movement of a pattern to movement of a point on the monitor.

8. The method of claim 7, wherein said step of processing the detected signals includes a step of transforming the detected signals to signals representing a mirror image of the movement of the pattern.

9. The method of claim 7, wherein said step of processing the transformed signals includes the step of selecting a transformation equation based on the displacement between the first sensor location and the second sensor location.

10. The method of claim 9, wherein said step of selecting a transformation equation is based on the angular displacement between the first sensor location and the second sensor location about a first axis of rotation.

11. The method of claim 10, wherein said step of selecting a transformation equation is based on the angular displacement between the first sensor location and the second sensor location about a second axis of rotation.

12. A method of converting detected signals into reported signals, the detected signals representing movement of a pattern relative to an optical sensor in a first location and the reported signals representing simulated movement of the pattern which would be detected if the optical sensor were in a second location, the second location corresponding to a user contact point of the pattern, said method comprising the steps of:

determining a conversion factor based on the displacement between the first location and the second location; and

applying the conversion factor to convert the detected signals into reported signals.

13. The method of claim 12, wherein said step of determining the conversion factor includes the steps of:

defining a first vector space as that occupied by the user contact point;

defining a second vector space as that occupied by the optical sensor;

defining a third vector space as that occupied by the simulated optical sensor, wherein the reported signals also occupy the third vector space; and

transforming movement of the pattern at the user contact point in the first vector space into the detected signals in the second vector space.

14. The method of claim 13, wherein the step of determining the conversion factor further includes the step of transforming the detected signals in the second vector space into reported signals in the third vector space such that the reported signals simulate signals which would be detected by a sensor in the second location.

15. The method of claim 14, wherein said step of transforming detected signals into reported signals includes the step of comparing detected counts with a table of look-up values to determine the appropriate reported signal.

16. The method of claim 15, wherein said step of transforming detected signals into reported signals includes the step of error correction to account for round-off error.

17. The method of claim 16, wherein said step of transforming detected signals into reported signals includes the step of error correction to account for multiple values of detected vector values mapping to a single reported vector value.

18. An optical pointing apparatus for controlling on-screen cursor movement of a monitor comprising:

a housing;

a ball with a predetermined all-over pattern coupled to said housing for rotation therein, said ball partially extending from said housing to present an ideal user contact location to enable rotational manipulation of said ball, the ideal user contact location defining a user vector space, the ideal user contact location also defining an ideal sensor location which is diametrically opposed thereto and parallel to a plane tangent to the ball;

a sensor disposed in said housing parallel to a plane tangent to the ball to detect movement of said ball by reading the pattern as it moves relative to said sensor, the sensor being angularly displaced from the ideal sensor location and occupying a sensor vector space; and

a microcontroller disposed in said housing and associated with said sensor, said microcontroller containing instructions to transform detected movement of the ball from said sensor into reported movement of the ball, reported movement being a simulation of detected movement if the sensor were in the ideal sensor location, the simulated movement occupying a reported vector space.