Handheld pointer device and tilt angle adjustment method thereof

• US 10,067,576 B2
• Filed: 05/08/2014
• Issued: 09/04/2018
• Est. Priority Date: 02/19/2013
• Status: Active Grant

• Current Assignee: PixArt Imaging Incorporated
• Original Assignee: PixArt Imaging Incorporated
• Inventors: Cheng, Han-Ping, Huang, Chao-Chien, Liang, Chia-Cheun
• Primary Examiner(s): Eisen, Alexander
• Assistant Examiner(s): Teshome, Kebede
• Application Number:
  US14/273,523
• Publication Number:
  US 20140247214A1
• Time in Patent Office: 1,580 Days
• Field of Search: None
• CPC Class Codes: G06F 3/017 Gesture based interaction, e.g. based on a set of recognized hand gestures interaction based on gestures traced on a digitiser G06F3/04883
• CPC Class Codes: G06F 3/0304 Detection arrangements using opto-electronic means constructional details of pointing devices not related to the detection arrangement using opto-electronic means G06F3/033; optical digitisers G06F3/042
• CPC Class Codes: G06F 3/033 Pointing devices displaced or positioned by the user , e.g. mice, trackballs, pens or joysticks; Accessories therefor digitisers characterised by the transducing means G06F3/041
• CPC Class Codes: G06F 3/0346 with detection of the device orientation or free movement in a 3D space, e.g. 3D mice, 6-DOF [six degrees of freedom] pointers using gyroscopes, accelerometers or tilt-sensors

Abstract

An exemplary embodiment of the present disclosure provides a handheld pointer device and a tilt angle adjustment method thereof. The tilt angle adjustment method includes the following steps. Images corresponding to the position of a reference point are captured as the handheld pointer device pointing toward the reference point to generate a plurality of frames. Whether the reference point has substantially moved is subsequently determined based on the plurality of frames. When determines that the reference point has not substantially moved, causes an accelerometer unit of the handheld pointer device to detect the accelerations thereof over various axes so as to update a first tilt angle being used currently to a second tilt angle, accordingly. The handheld pointer device may thus accurately and efficiently calculate the relative position of the reference point with the appropriate tilt angle of the handheld pointer device used.

Claims

1. A tilt angle adjustment method of a handheld pointer device, comprising:

capturing consecutively, by an image capturing unit of the handheld pointer device, images of only one light spot of a reference point as the handheld pointer device pointing toward a position of the reference point and generating a plurality of frames containing the image of the reference point, wherein the handheld pointer device is at a first tilt angle, the first tilt angle is used for pointing position calculation, and the image capturing unit includes only one sensor;

determining whether or not the reference point has substantially moved according to the frames so as to determine whether to update the first tilt angle currently used in calculating a pointing coordinate or a movement information of the handheld pointer device relative the reference point, wherein to determine whether the reference point has substantially moved is to determine whether image positions of the reference point in the frames have substantially moved, and the pointing coordinate or the movement information of the handheld pointer device relative the reference point is calculated based on the first tilt angle and one of the frames;

when determined that the reference point has not substantially moved, operatively causes an accelerometer unit of the handheld pointer device to detect the accelerations of the handheld pointer device over multiple axes and correspondingly update the first tilt angle currently used to a second tilt angle according to the accelerations of the point device detected, wherein the second tilt angle is calculated by a processing unit of the handheld pointer device using with the accelerations detected; and

when determined that the reference point has substantially moved, continues to use the first tilt angle of the handheld pointer device for pointing position calculation.

2. The tilt angle adjustment method of claim 1, wherein the step of determining whether or not the reference point has substantially moved comprises:

calculating a position displacement between the image positions of the reference point in a first frame and a second frame successive to the first frame among the frames captured;

determining whether the position displacement of the reference point is less than a predefined displacement threshold; and

when the position displacement of the reference point is less than the predefined displacement threshold, determines that the reference point has not substantially moved.

3. The tilt angle adjustment method of claim 1, wherein the step of determining whether or not the reference point has substantially moved comprises:

calculating a velocity of the reference point based on the image positions of the reference point in a first frame and a second frame successive to the first frame among the frames captured;

determining whether or not the velocity of the reference point is greater than a predefined velocity threshold; and

when the velocity of the reference point is less than the predefined velocity threshold, determines that the reference point has not substantially moved.

4. The tilt angle adjustment method of claim 3, wherein the velocity of the reference point is calculated using the following equation:

5. The tilt angle adjustment method of claim 1, wherein the step of determining whether or not the reference point has substantially moved comprises:

calculating a first velocity of the reference point based on the image positions the reference point in a first frame and a second frame successive to the first frame among the frames captured;

calculating a second velocity of the reference point based on the image positions of the reference point in the second frame and a third frame successive to the second frame among the frames captured;

calculating an acceleration of the reference point based on the difference between the first velocity and the second velocity;

determining whether the acceleration of the reference point is greater than a predefined acceleration threshold; and

when the acceleration of the reference point is less than the predefined acceleration threshold, determines that the reference point has not substantially moved.

6. The tilt angle adjustment method of claim 5, wherein the first velocity of the reference point is calculated using the following equation:

7. The tilt angle adjustment method of claim 5, wherein the step of determining whether or not the reference point has substantially moved comprises:

causing the accelerometer unit to detect the accelerations of the handheld pointer device over multiple axes to generate an acceleration vector;

determining whether or not the magnitude of the acceleration vector is equal to a gravitational acceleration of the handheld pointer device; and

when the magnitude of the acceleration vector is equal to the gravitational acceleration of the handheld pointer device, determines that the reference point has not substantially moved.

8. The tilt angle adjustment method of claim 1, wherein the step of determining whether or not the reference point has substantially moved comprises:

causing the accelerometer unit to detect the accelerations of the handheld pointer device over multiple axes to generate an acceleration vector;

determining whether or not the magnitude of the acceleration vector is equal to a gravitational acceleration of the handheld pointer device; and

when the magnitude of the acceleration vector is equal to the gravitational acceleration of the handheld pointer device, determines that the reference point has not substantially moved.

9. A tilt angle adjustment method of a handheld pointer device, comprising:

capturing consecutively, by an image capturing unit of the handheld pointer device, images of only one light spot of a reference point as the handheld pointer device pointing toward a position of the reference point and generating a plurality of frames containing the image of the reference point, wherein the handheld pointer device is at a first tilt angle, the first tilt angle is used for pointing position calculation, and the image capturing unit includes only one sensor;

calculating an acceleration of the reference point based on image positions of the reference point in three consecutive frames;

determining whether the acceleration of the reference point is zero so as to determine whether to update the first tilt angle currently used in calculating a pointing coordinate or a movement information of the handheld pointer device relative the reference point, wherein the pointing coordinate or the movement information of the handheld pointer device relative the reference point is calculated based on the first tilt angle and one of the three consecutive frames; and

when determined that the acceleration of the reference point is zero, causes an accelerometer unit of the handheld pointer device to detect the accelerations of the handheld pointer device over multiple axes and correspondingly update the first tilt angle currently used to a second tilt angle calculated according to the accelerations of point device detected, wherein the second tilt angle is calculated by a processing unit of the handheld pointer device using with the accelerations detected;

wherein the step of calculating the acceleration of the reference point comprises;

calculating a first velocity of the reference point based on the image positions of the reference point in a first frame and a second frame among the three consecutive frames captured;

calculating a second velocity of the reference point based on the image positions of the reference point in the second frame and a third frame among the three consecutive frames captured;

calculating the acceleration of the reference point based on the difference between the first velocity and the second velocity.

10. The tilt angle adjustment method of claim 9, wherein the step after determined that the acceleration of the reference point is zero comprises:

causing the accelerometer unit to detect the accelerations of the handheld pointer device over the multiple axes of the handheld pointer device to generate an acceleration vector;

determining whether or not the magnitude of the acceleration vector is equal to a gravitational acceleration of the handheld pointer device; and

when determined that the magnitude of the acceleration vector of the reference point is equal to the gravitational acceleration of the handheld pointer device, correspondingly update the first tilt angle currently used to the second tilt angle calculated according to the accelerations of the handheld pointer device.

11. The tilt angle adjustment method of claim 9, wherein the first velocity of the reference point is calculated using the following equation:

12. A handheld pointer device, comprising:

an image capturing unit, configured to consecutively capture images of only one light spot of a reference point as the handheld pointer device pointing toward a position of the reference point and sequentially generate a plurality of frames containing the image of the reference point, wherein the handheld pointer device is at a first tilt angle, the first tilt angle is used for pointing position calculation, and the image capturing unit includes only one sensor;

an accelerometer unit, configured to detect a plurality of accelerations of the handheld pointer device over multiple axes for generating an acceleration vector; and

a processing unit coupled to the image capturing unit and the accelerometer unit, configured to operatively determine whether or not the reference point has substantially moved according to the frames so as to determine whether to update the first tilt angle currently used in calculating a pointing coordinate or a movement information of the handheld pointer device relative the reference point, wherein to determine whether the reference point has substantially moved is to determine whether image positions of the reference point in the frames have substantially moved, and the pointing coordinate or the movement information of the handheld pointer device relative the reference point is calculated based on the first tilt angle and one of the frames;

wherein when the processing unit determines that the reference point has not substantially moved, the processing unit operatively causes the accelerometer unit to detect the accelerations of the handheld pointer device over multiple axes and correspondingly update the first tilt angle currently used to a second tilt angle calculated according to the accelerations of the handheld pointer device, wherein the second tilt angle is calculated by a processing unit of the handheld pointer device using with the accelerations detected;

wherein when determined that the reference point has substantially moved, continues to use the first tilt angle of the handheld pointer device for pointing position calculation.

13. The handheld pointer device of claim 12, wherein the processing unit calculates the position displacement between the image positions of the reference point in a first frame and a second frame among the frames captured to determine whether or not the image positions of the reference point has substantially moved in the first frame and the second frame according to the position displacement.

14. The handheld pointer device of claim 12, wherein the processing unit calculates a velocity of the reference point based on the image positions the reference point in a first frame and a second frame among the frames captured to determine whether or not the image position of the reference point has substantially moved in the first frame and the second frame according to the velocity of the reference point.

15. The handheld pointer device of claim 14, wherein the processing unit calculates the velocity of the reference point using the following equation:

16. The handheld pointer device of claim 12, wherein the processing unit calculates the image positions of the reference point in a first frame and a second frame among the three consecutive frames to generate a first velocity of the reference point, and the processing unit calculates the image positions of the reference point in the second frame and a third frame to generate a second velocity of the reference point;

wherein the processing unit calculates the difference between the first velocity and the second velocity to generate an acceleration of the reference point between the first frame and the third frame, the process unit determines whether or not the image position of the reference point has substantial moved according to the acceleration of the reference point.

17. The handheld pointer device of claim 16, wherein the processing unit calculates the first velocity of the reference point using the following equation:

18. The handheld pointer device of claim 12, wherein the accelerometer unit is an accelerometer or a gravitational sensor.

19. A handheld pointer device comprising:

an image capturing unit, configured to consecutively capture images of only one light spot of a reference point as the handheld pointer device pointing toward a position of the reference point and sequentially generate a plurality of frames containing the image of the reference point, wherein the handheld pointer device is at a first tilt angle, the first tilt angle is used for pointing position calculation, and the image capturing unit includes only one sensor;

an accelerometer unit, configured to operatively detect a plurality of accelerations of the handheld pointer device over multiple axes for generating an acceleration vector; and

a processing unit coupled to the image capturing unit and the accelerometer unit, configured for operatively calculating an acceleration of the reference point based on the image positions of the reference point in three consecutive frames and determining whether the acceleration of the reference point is zero so as to determine whether to update the first tilt angle currently used in calculating a pointing coordinate or a movement information of the handheld pointer device relative the reference point, wherein the pointing coordinate or the movement information of the handheld pointer device relative the reference point is calculated based on the first tilt angle and one of the three consecutive frames;

wherein when the processing unit determines that the acceleration of the reference point is zero, the processing unit causes the accelerometer unit to detect the accelerations of the handheld pointer device over multiple axes and correspondingly updates the first tilt angle currently used to a second tilt angle calculated according to the accelerations of the handheld pointer device, wherein the second tilt angle is calculated by a processing unit of the handheld pointer device using with the accelerations detected;

wherein the processing unit calculates the image positions of the reference point in a first frame and a second frame among the three consecutive frames to generate a first velocity of the reference point, and the processing unit calculates the image positions of the reference point in the second frame and a third frame to generate a second velocity of the reference point;

wherein the processing unit calculates the difference between the first velocity and the second velocity to generate the acceleration of the reference point between the first frame and the third frame.

20. The handheld pointer device of claim 19, wherein when the processing unit determines that the acceleration of reference point is zero, the processing unit determines whether the magnitude of the acceleration vector is equal to a gravitational acceleration of the handheld pointer device and correspondingly updates the first tilt angle currently used to the second tilt angle calculated according to the accelerations of the handheld pointer device.

21. The handheld pointer device of claim 19, wherein the processing unit calculates the first velocity of the reference point using the following equation:

22. The handheld pointer device of claim 19, wherein the accelerometer unit is an accelerometer or a gravitational sensor.

23. The handheld pointer device of claim 19, wherein when the processing unit determines that the acceleration of the reference point in the consecutive frames is greater than a predefined acceleration threshold, the processing unit does not update the first tilt angle of the handheld pointer device currently used and continues to use the first tilt angle to calculate the image position of the reference point in one of the frames.

24. A tilt angle adjustment method of a handheld pointer device, comprising:

capturing consecutively, by an image capturing unit of the handheld pointer device, images of only one light spot of a reference point as the handheld pointer device pointing toward a position of the reference point and generating a plurality of frames containing the image of the reference point, wherein the handheld pointer device is at a first tilt angle, the first tilt angle is used for pointing position calculation, and the image capturing unit includes only one sensor;

determining whether or not the reference point has substantially moved according to the frames so as to determine whether to update the first tilt angle currently used in calculating a pointing coordinate or a movement information of the handheld pointer device relative the reference point, wherein to determine whether the reference point has substantially moved is to determine whether image positions of the reference point in the frames have substantially moved, and the pointing coordinate or the movement information of the handheld pointer device relative the reference point is calculated based on the first tilt angle and one of the frames; and

when determined that the reference point has substantially moved, continuing to use the first tilt angle of the handheld pointer device for pointing position calculation;

wherein the step of determining whether or not the reference point has substantially moved comprises;

calculating a first velocity of the reference point based on image positions the reference point in a first frame and a second frame successive to the first frame among the frames captured;

calculating a second velocity of the reference point based on the image positions of the reference point in the second frame and a third frame successive to the second frame among the frames captured;

calculating an acceleration of the reference point based on the difference between the first velocity and the second velocity;

determining whether the acceleration of the reference point is greater than a predefined acceleration threshold; and

when the acceleration of the reference point is less than the predefined acceleration threshold, determining that the reference point has not substantially moved.