Reporting optical tracking data based on integrated resolution switching and surface detection

• US 8,169,420 B2
• Filed: 02/05/2008
• Issued: 05/01/2012
• Est. Priority Date: 02/05/2008
• Status: Active Grant

• Current Assignee: PixArt Imaging Incorporated
• Original Assignee: Avago Technologies ECBU IP Singapore Pte Limited (Broadcom, Inc.)
• Inventors: Lee, Wui Pin, Ang, Jin Kiong
• Primary Examiner(s): Hjerpe, Richard
• Assistant Examiner(s): HARRIS, DOROTHY H
• Application Number:
  US12/025,951
• Publication Number:
  US 20090195503A1
• Time in Patent Office: 1,547 Days
• Field of Search: 345157-167
• US Class Current: 345/175
• CPC Class Codes: G06F 3/0317 in co-operation with a patterned surface, e.g. absolute position or relative movement detection for an optical mouse or pen positioned with respect to a coded surface

Abstract

An integrated resolution switching surface detection system for an optical navigation device. The integrated resolution switching surface detection system includes a resolution switching engine, a surface detection engine, and a navigation engine. The resolution switching engine sets a resolution status based on a motion speed of a tracking surface relative to a navigation sensor, wherein the motion speed is a measure of motion data over time. The surface detection engine sets a surface detection status based on the resolution status that is set by the resolution engine. The navigation engine reads motion data from the navigation sensor and reports the motion data to a computing device according to the surface detection status that is set by the surface detection engine. Embodiments of the integrated resolution switching surface detection system maintain smooth and predictable cursor movement associated with a plurality of finger assert and finger de-assert events.

Claims

1. An optical navigation system comprising:

a resolution switching engine to set a resolution status based on a motion speed of a tracking surface relative to an optical finger navigation sensor, wherein the motion speed is a measure of motion data over time;

a surface detection engine coupled to the resolution switching engine, the surface detection engine to set a surface detection status based on the present resolution status that is set by the resolution switching engine; and

a navigation engine coupled to the surface detection engine, the navigation engine to read the motion data from the navigation sensor and to report the motion data to a computing device according to the present surface detection status that is set by the surface detection engine in response to the detection engine detecting a shutter value below a first threshold value, and wherein the navigation engine is further configured to discard the motion data from the navigation sensor in response to the surface detection engine detecting a shutter value above a second threshold value.

2. The optical navigation system of claim 1, further comprising a timer coupled to the resolution switching engine, the timer to trigger the resolution switching engine to start an integrated resolution switching surface detection test cycle, wherein the navigation engine is further configured to report the motion data to the computing device according to a surface detection status determined in the integrated resolution switching surface detection test cycle.

3. The optical navigation system of claim 2, wherein the navigation engine is further configured to multiply the motion data by a scalar and report the scaled motion data to the computing device, wherein a value of the scalar is determined according to the present resolution status.

4. The optical navigation system of claim 1, wherein the surface detection engine is further configured to adapt a comparison of the shutter value to at least one of a plurality of surface detection thresholds according to the present resolution status.

5. The optical navigation system of claim 4, wherein the surface detection engine is further configured to provide a hysteresis window based on the comparison of the shutter value to at least one of the plurality of surface detection thresholds, wherein the hysteresis window reduces a surface detection status oscillation.

6. The optical navigation system of claim 1, wherein the surface detection engine is further configured to compare a surface quality value to one of a plurality of surface detection thresholds, wherein the surface detection engine is further configured to set the surface detection status based on the comparison and the present resolution status.

7. The optical navigation system of claim 1, wherein the surface detection engine is further configured to accumulate an absolute value of subsequent motion data that is read by the navigation engine during a current integrated resolution switching surface detection test cycle.

8. The optical navigation system of claim 7, further comprising a buffer coupled to the surface detection engine, the buffer to store the absolute value of the motion data accumulated by the surface detection engine for use in a subsequent integrated resolution switching surface detection test cycle.

9. A method comprising:

setting a resolution status based on a motion speed of a tracking surface relative to an optical finger navigation sensor, wherein the motion speed is a measure of motion data over time;

setting a surface detection status based on the present resolution status that is set by a resolution switching engine; and

reading motion data from the navigation sensor and reporting the motion data to a computing device according to the present surface detection status that is set by a surface detection engine in response to detecting a shutter value below a first threshold value; and

discarding the motion data from the navigation sensor in response to detecting a shutter value above a second threshold value.

10. The method of claim 9 further comprising triggering the resolution switching engine to start an integrated resolution switching surface detection test cycle, wherein the motion data is reported to the computing device according to the surface detection status that is determined in said integrated resolution switching surface detection test cycle.

11. The method of claim 10 further comprising multiplying the motion data by a scalar and reporting the scaled motion data to the computing device, wherein a value of the scalar is determined according to the present resolution status.

12. The method of claim 9 further comprising adapting a comparison of the shutter value to at least one of a plurality of surface detection thresholds according to the present resolution status.

13. The method of claim 12 further comprising defining the plurality of surface detection thresholds such that the comparison of the shutter value to at least one of the plurality of surface detection thresholds provides a hysteresis window, wherein the hysteresis window reduces a surface detection status oscillation.

14. The method of claim 9 further comprising comparing a surface quality value to one of a plurality of surface detection thresholds, wherein the surface detection engine sets the surface detection status based on said comparison and the present resolution status.

15. The method of claim 9 further comprising buffering an absolute value of motion data that is accumulated by the surface detection engine for use in a subsequent integrated resolution switching surface detection test cycle.

16. An optical finger navigation system, the optical finger navigation system comprising:

a light source to illuminate a tracking surface, wherein the tracking surface comprises a finger of a user;

a navigation sensor to detect motion data relative to the tracking surface, wherein the motion data comprises a first displacement in a first direction and a second displacement in a second direction;

a time based resolution switching engine to set a resolution status according to a comparison of a detected speed of the motion data to one of a plurality of resolution thresholds, wherein the speed of the motion data is a distance the tracking surface moves over a certain period of time as detected by the navigation sensor;

a resolution based surface detection engine to set a surface detection status based on the present resolution status and a present shutter value;

a plurality of surface detection thresholds, wherein the plurality of surface detection thresholds provide a hysteresis window to reduce a surface detection status oscillation; and

an adaptive navigation sensor to report motion data read from the navigation sensor to a computing device in response to detecting a shutter value at a first threshold value and wherein the navigation sensor is configured to discard the motion data in response to detecting a shutter value at a second threshold value according to the surface detection status that is determined in an integrated resolution switching surface detection test cycle.