SYSTEM AND METHOD FOR AUTOMATICALLY ADJUSTING LIGHT SOURCE DRIVE CURRENT DURING OPTICAL NAVIGATION OPERATION

• US 20100289745A1
• Filed: 05/14/2009
• Published: 11/18/2010
• Est. Priority Date: 05/14/2009
• Status: Active Grant

• Current Assignee: PixArt Imaging Incorporated
• Original Assignee: Avago Technologies ECBU IP Singapore Pte Limited (Broadcom, Inc.)
• Inventors: Yap, Suk Lai, Lye, Andy Beng Chye, Lee, Siew Chin
• Granted Patent: US 8,537,109 B2
• Time in Patent Office: Days
• US Class Current: 345/166
• 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
• CPC Class Codes: G06F 3/03543 Mice or pucks G06F3/03541 takes precedence
• CPC Class Codes: G06F 3/038 Control and interface arrangements therefor, e.g. drivers or device-embedded control circuitry

Abstract

A system and method for automatically adjusting a drive current to a light source during an optical navigation operation uses brightness characteristics of captured frames of image data to determine whether each of the frames of image data belongs to one of at least first and second types of frames of image data. The drive current is adjusted depending on counts of the frames of image data belonging to the first and second types of frames of image data.

Claims

1. A system for performing an optical navigation operation, the system comprising:

a driver circuit configured to provide a drive current to a light source to produce light on a target surface;

an image sensor configured to capture frames of image data of the target surface illuminated by the light;

a navigation engine operably connected to the image sensor to receive the frames of image data, the navigation engine being configured to generate displacement values based on comparisons of the frames of image data; and

an automatic drive current adjuster operably connected to the image sensor to receive the frames of image data, the automatic drive current adjuster being configured to determine whether each of the frames of image data belongs to one of at least first and second types of frames of image data with respect to brightness characteristics of the frames of image data, the automatic drive current adjuster being further configured to count the frames of image data belonging to the first and second types of frames of image data, the automatic drive current adjuster being further configured to direct the driver circuit to adjust the drive current to the light source depending on counts of the frames of image data belonging to the first and second types of frames of image data.

2. The system of claim 1 wherein the automatic drive current adjuster is configured to compare a current shutter value to a threshold shutter value to determine whether each of the frames of image data belongs to one of at least the first and second types of frames of image data.

3. The system of claim 1 wherein the automatic drive current adjuster is configured to compare an average pixel value of each of the frames of image data to a threshold average value to determine whether each of the frames of image data belongs to one of at least the first and second types of frames of image data.

4. The system of claim 1 wherein the automatic drive current adjuster is configured to direct the driver circuit to reduce the drive current to the light source when the count of the frames of image data belonging to the first type of frames of image data reaches a first predefined value.

5. The system of claim 4 wherein the automatic drive current adjuster is configured to increase the count of the frames of image data belonging to the first type of frames of image data when a frame of image data has been determined to belong to the first type of frames of image data and when the count of the frames of image data belonging to the first type of frames of image data is less than the first predefined value.

6. The system of claim 5 wherein the automatic drive current adjuster is configured to reset the count of the frames of image data belonging to the second type of frames of image data when the count of the frames of image data belonging to the first type of frames of image data is increased.

7. The system of claim 4 wherein the automatic drive current adjuster is configured to direct the driver circuit to increase the drive current to the light source when the count of the frames of image data belonging to the second type of frames of image data reaches a second predefined value.

8. The system of claim 7 wherein the automatic drive current adjuster is configured to increase the count of the frames of image data belonging to the second type of frames of image data when a frame of image data has been determined to belong to the second type of frames of image data and when the count of the frames of image data belonging to the second type of frames of image data is less than the second predefined value.

9. The system of claim 8 wherein the automatic drive current adjuster is configured to reset the count of the frames of image data belonging to the first type of frames of image data when the count of the frames of image data belonging to the second type of frames of image data is increased.

10. A method for automatically adjusting a drive current to a light source during an optical navigation operation, the method comprising:

providing the drive current to the light source to produce light on a target surface;

capturing frames of image data of the target surface illuminated by the light;

generating displacement values based on comparisons of the frames of image data;

determining whether each of the frames of image data belongs to at least one of first and second types of frames of image data with respect to brightness characteristics of the frames of image data;

counting the frames of image data belonging to the first and second types of frames of image data; and

automatically adjusting the drive current to the light source depending on counts of the frames of image data belonging to the first and second types of frames of image data.

11. The method of claim 10 wherein the determining includes comparing a current shutter value to a threshold shutter value to determine whether each of the frames of image data belongs to one of at least the first and second types of frames of image data.

12. The method of claim 10 wherein the determining includes comparing an average pixel value of each of the frames of image data to a threshold average value to determine whether each of the frames of image data belongs to one of at least the first and second types of frames of image data.

13. The method of claim 10 wherein the automatically adjusting includes decreasing the drive current to the light source when the count of the frames of image data belonging to the first type of frames of image data reaches a first predefined value.

14. The method of claim 13 wherein the counting includes increasing the count of the frames of image data belonging to the first type of frames of image data when a frame of image data has been determined to belong to the first type of frames of image data and when the count of the frames of image data belonging to the first type of frames of image data is less than the first predefined value.

15. The method of claim 14 further comprising resetting the count of the frames of image data belonging to the second type of frames of image data when the count of the frames of image data belonging to the first type of frames of image data is increased.

16. The method of claim 13 wherein the automatically adjusting includes increasing the drive current to the light source when the count of the frames of image data belonging to the second type of frames of image data reaches a second predefined value.

17. The method of claim 16 wherein the counting includes increasing the count of the frames of image data belonging to the second type of frames of image data when a frame of image data has been determined to belong to the second type of frames of image data and when the count of the frames of image data belonging to the second type of frames of image data is less than the second predefined value.

18. The method of claim 17 further comprising resetting the count of the frames of image data belonging to the first type of frames of image data when the count of the frames of image data belonging to the second type of frames of image data is increased.

19. A method for automatically adjusting a drive current to a light source during an optical navigation operation, the method comprising:

providing the drive current to the light source to produce light on a target surface;

capturing frames of image data of the target surface illuminated by the light;

generating displacement values based on comparisons of the frames of image data;

determining whether each of the frames of image data belongs to at least one of first and second types of frames of image data, including comparing a current shutter value to a threshold shutter value;

counting the frames of image data belonging to the first and second types of frames of image data; and

automatically adjusting the drive current to the light source depending on counts of the frames of image data belonging to the first and second types of frames of image data.

20. The method of claim 19 wherein the automatically adjusting includes reducing the drive current to the light source when the count of the frames of image data belonging to the first type of frames of image data reaches a first predefined value and increasing the drive current to the light source when the count of the frames of image data belonging to the second type of frames of image data reaches a second predefined value.