Granted Patent B2

US 8,928,626 · App. 13/095,576 · Granted Jan 6, 2015

Abstract

Claims (35)

1. An optical navigation system comprising:

a light source configured to emit light;

a sensor configured to capture a light-on frame and a light-off frame; wherein both frames are captured at a shutter value;

an object detection engine coupled to the sensor, the object detection engine configured to determine a first set number for photosensitive pixel elements used in acquiring the light-on frame and a second set number for photosensitive pixel elements used in acquiring the light-off frame, the object detection engine is configured to report a motion data by comparing a scaled-up pixel value with a threshold value; and

a calculator of the object detection engine configured to calculate the scaled-up pixel value, wherein the calculator is configured to determine a pixel difference between the first set number and the second set number to determine a ratio of the pixel difference to the shutter value, and to multiply the ratio with a multiplying factor.

2. The optical navigation system of claim 1 , wherein the object detection engine is configured to report the motion data if the scaled-up pixel value is greater than the threshold value.

3. The optical navigation system of claim 1 , wherein the object detection engine is configured to report a presence of an object if the scaled-up pixel value is greater than the threshold value.

4. The optical navigation system of claim 3 , wherein the object detection engine is configured to report the motion data upon determining the presence of the object.

5. The optical navigation system of claim 3 , wherein the threshold value is a predetermined minimum scaled-up value at which the object detection engine detects the presence of the object.

6. The optical navigation system of claim 1 , further comprising a memory configured to store the threshold value, the first set number and the second set number.

7. The optical navigation system of claim 6 , wherein the object detection engine is configured to calculate subsequent scaled-up pixel value without the light-on frame.

8. The optical navigation system of claim 7 , wherein the object detection engine is configured to calculate subsequent scaled-up value based on the first set number and the shutter value stored in the memory, and a new second set number from a current light-off frame.

9. An optical navigation method comprising:

capturing a light-on frame and a light-off frame at a same shutter value;

determining a first set number for photosensitive pixel elements used in acquiring the light-on frame and a second set number for photosensitive pixel elements used in acquiring the light-off frame;

calculating the scaled-up pixel value based on the first set number, the second set number and the shutter value at least by:

determining a pixel difference between the first set number and the second set number; and

determining a ratio of the pixel difference to the shutter value, and multiplying the ratio with a multiplying factor;

reporting a motion data upon determining a presence of an object by comparing the scaled-up pixel value with a threshold value.

10. The method of claim 9 , further comprising reporting the motion data upon determining the scaled-up pixel value is greater than the threshold value.

11. The method of claim 9 , further comprising reporting the presence of the object if the scaled-up pixel value is greater than the threshold value.

12. The method of claim 9 , wherein the threshold value is a predetermined minimum scaled-up value at which the object detection engine detects the presence of the object is detected.

13. The method of claim 9 , further comprising storing the first set number and the second set number and the threshold value in a memory.

14. The method of claim 13 , further comprising calculating a subsequent scaled-up value based on the first set number and the shutter value stored in the memory, and a new second set number from current light-off frame.

15. An optical navigation device comprising:

a light source configured to emit light;

a sensor configured to capture a light-on frame and a subsequent light-off frame wherein both frames are captured at a same shutter value;

a navigation engine configured to provide a navigation operation; and

an object detection engine coupled to the sensor and the navigation engine, the object detection engine configured to determine a first set number for photosensitive pixel elements used in acquiring the light-on frame and a second set number for photosensitive pixel elements used for acquiring the light-off frame, the object detection engine is configured to report a motion data for navigation operation by comparing a scaled-up pixel value with a threshold value;

wherein the object detection engine is configured to calculate the scaled-up pixel value using the first set number, the second set number and the shutter value, and

wherein the object detection engine is configured to calculate subsequent scaled-up pixel value without a light-on frame.

16. The optical navigation device of claim 15 , wherein the object detection engine is configured to report the motion data if the scaled-up pixel value is greater than the threshold value.

17. The optical navigation device of claim 15 , wherein the object detection engine comprises a calculator configured to calculate the scaled-up pixel value.

18. The optical navigation device of claim 17 , wherein the calculator is configured to determine a pixel difference between the first set number and the second set number.

19. The optical navigation device of claim 18 , wherein the calculator is configured to determine a ratio of the pixel difference to the shutter value, and configured to multiply the ratio with a multiplying factor.

Assignments (8)