SENSING METHOD AND DEVICE

• US 20120287443A1
• Filed: 05/07/2012
• Published: 11/15/2012
• Est. Priority Date: 05/09/2011
• Status: Active Grant

• Current Assignee: PixArt Imaging Incorporated
• Original Assignee: Hung-Yu Lin
• Inventors: LIN, Hung-Yu, WU, Chun-Jung
• Granted Patent: US 9,012,828 B2
• Time in Patent Office: Days
• US Class Current: 356/622
• CPC Class Codes: G01B 11/026 by measuring distance between sensor and object G01B11/0608 takes precedence
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen

Abstract

A sensing method and device for sensing the position of an object are provided. The sensing device comprises a light source for generating a plane light, and a sensor unit disposed at one side of the light source. The sensing method comprises driving the light source to generate the plane light, forming a reflective light distribution by the object reflecting the plane light; and estimating a relative distance between the object and the light source according to the reflective light distribution.

Claims

1. A method for sensing a position of an object, comprising:

driving a light source to generate a plane light;

reflecting the plane light by the object to form a reflective light distribution; and

estimating a relative distance between the object and the light source according to the reflective light distribution.

2. The method according to claim 1, wherein the light source is a laser diode or a light-emitting diode (LED).

3. The method according to claim 1, wherein the light source emits an emergent ray, and the step of driving the light source to generate the plane light comprises:

the emergent ray generating the plane light by passing through a cylindrical lens;

or

the emergent ray generating the plane light by passing through a rotatable micro-electromechanical (MEM) mirror.

4. The method according to claim 1, wherein the step of estimating the relative distance between the object and the light source according to the reflective light distribution comprises:

obtaining a first image including the reflective light distribution; and

obtaining a first position parameter according to a plurality of pixels corresponding to the reflective light distribution of the first image.

5. The method according to claim 4, wherein the step of obtaining the first position parameter comprises:

performing a calculation for a position of center of mass of the plurality of pixels corresponding to the reflective light distribution of the first image to obtain the first position parameter; and

estimating the relative distance between the object and the light source according to a reference record and the first position parameter.

6. The method according to claim 5, wherein the reference records comprise a plurality of reference position parameters, and the reference position parameters are obtained by a setting process in which the object is disposed apart from the light source at a plurality of preset relative distances and the position of center of mass is calculated for each of a plurality of reference reflective light distribution formed by reflecting the plane light.

7. The method according to claim 5, wherein the step of performing the calculation for the position of center of mass of the plurality of pixels comprises performing a calculation for the position of center of mass by using brightness of each pixel of the plurality of pixel as weight of each pixel, the number of the plurality of pixels, and positions of the plurality of pixels on the first image.

8. The method according to claim 4, further comprising:

obtaining a second image including a reflective light distribution; and

obtaining a second position parameter according to a plurality of pixels corresponding to the reflective light distribution of the second image.

9. The method according to claim 8, wherein the first image and the second image are obtained respectively by a first sensor unit and a second sensor unit, and the first sensor unit and the second sensor unit are respectively disposed at each side of the light source.

10. The method according to claim 9, wherein the light source is adapted to generate a emergent ray used for forming the plane light, and distance on a vertical direction between the first sensor unit and a horizontal plane of the emergent ray is different from distance on the vertical direction between the second sensor unit and the horizontal plane of the emergent ray.

11. The method according to claim 1, wherein the step of estimating the relative distance between the object and the light source according to the reflective light distribution comprises:

obtaining a first relative distance between the object and the light source at a first time point;

obtaining a second relative distance between the object and the light source at a second time point; and

obtaining movement of the object between the first time point and the second time point according to the first relative distance and the second relative distance.

12. The method according to claim 1, wherein the plane light defines a sensing area on a real touch plane or on a stereoscopic operation plane.

13. A device for sensing a position of an object, comprising:

a light source for generating a plane light; and

a first sensor unit disposed at one side of the light source for estimating a relative distance between the object and the light source according to a reflective light distribution, wherein the reflective light distribution is formed by the object reflecting the plane light.

14. The device according to claim 13, wherein the light source is a laser diode or a light-emitting diode.

15. The device according to claim 13, wherein the light source emits an emergent ray, and the emergent ray generates the plane light by passing through a cylindrical lens or a rotatable micro-electromechanical (MEM) mirror.

16. The device according to claim 13, further comprising a control unit having a signal connection with the first sensor unit, the first sensor unit sensing a first image including the reflective light distribution, and a first position parameter being obtained according to a plurality of pixels corresponding to the reflective light distribution of the first image.

17. The device according to claim 16, further comprising a storage unit having a signal connection with the control unit, a reference record being provided to the control unit, wherein the control unit performs a calculation for a position of center of mass of the plurality of pixels and obtains the first position parameter, and estimates the relative distance between the object and the light source according to the reference record and the first position parameter.

18. The device according to claim 17, wherein the reference records comprises a plurality of reference position parameters, and the reference position parameters are obtained by a setting process in which the object is disposed apart from the light source at a plurality of preset relative distances and the position of center of mass is calculated for each of a plurality of reference reflective light distributions formed by reflecting the plane light.

19. The device according to claim 17, wherein the calculation for the position of center of mass comprises using brightness of each pixel as weight of each pixel, the number of the plurality of pixels, and positions of the plurality of pixels on the first image.

20. The device according to claim 16, further comprising a second sensor unit having a signal connection with the control unit, wherein the second sensor unit estimating the relative distance between the object and the light source according to a reflective light distribution, wherein the reflective light distribution is formed by the object reflecting the plane light.

21. The device according to claim 20, wherein the first sensor unit and the second sensor unit are disposed at each side of the light source.

22. The device according to claim 21, wherein the light source is adapted to generate a emergent ray used for forming the plane light, and distance on a vertical direction between the first sensor unit and a horizontal plane of the emergent ray is different from distance on the vertical direction between the second sensor unit and the horizontal plane of the emergent ray.

23. The device according to claim 21, further comprising an adjusting unit disposed between the first sensor unit and the second sensor unit for dynamically adjusting a horizontal distance between the first sensor unit and the second sensor unit.

24. The device according to claim 13, wherein the first sensor unit obtaining a first relative distance between the object and the light source at a first time point, obtaining a second relative distance between the object and the light source at a second time point, and obtaining movement of the object between the first time point and the second time point according to the first relative distance and the second relative distance.

25. The device according to claim 13, further comprising a transmission unit electrically connected to the sensing unit, the transmission unit being configured to transmit sensed images to a host having a signal connection to the device and to convert the relative distance between the object and the light source to a cursor display.

26. The device according to claim 13, wherein the plane light defines a sensing area on a real touch plane or on a stereoscopic operation plane.

27. A device for sensing a position of an object, comprising:

a light source for generating a plane light; and

a sensor unit disposed at one side of the light source, for estimating a relative distance between the light source and the object according to a reflective light distribution, wherein the reflective light distribution is formed by the object reflecting the plane light.

28. The device according to claim 27, wherein the light source is a laser or a light-emitting diode (LED).

29. The device according to claim 27, wherein the light source emits an emergent ray, and the emergent ray generates the plane light by passing through a cylindrical lens or a micro-electromechanical (MEM) mirror.

30. The device according to claim 27, further comprising a control unit having a signal connection with first sensor unit, wherein the first sensor unit sensing a first image including the reflective light distribution, and a first position parameter being obtained according to a plurality of pixels corresponding to the reflective light distribution of the first image.

31. The device according to claim 30, further comprising a storage unit having a signal connection with the control unit, a reference record being provided to the control unit, wherein the control unit performs a calculation for a position of center of mass of the plurality of pixels and obtains the first position parameter, and estimates the relative distance between the object and the light source according to the reference record and the first position parameter.

32. The device according to claim 31, wherein the reference records comprises a plurality of reference position parameters, and the reference position parameters are obtained by a setting process in which the object is disposed apart from the light source at a plurality of preset relative distances and the position of center of mass is calculated for each of a plurality of reference reflective light distributions formed by reflecting the plane light.

33. The device according to claim 31, wherein the calculation of the position of center of mass comprises using brightness of each pixel as weight of each pixel, the number of the plurality of pixels, and positions of the plurality of pixels on the first image.

34. The device according to claim 30, further comprising a second sensor unit having a signal connection with the control unit, the second sensor unit estimating the relative distance between the object and the light source according to a reflective light distribution, wherein the reflective light distribution is formed by the object reflecting the plane light.

35. The device according to claim 34, wherein the first sensor unit and the second sensor unit are disposed at each side of the light source.

36. The device according to claim 35, wherein the light source is adapted to generate a emergent ray used for forming the plane light, and distance on a vertical direction between the first sensor unit and a horizontal plane of the emergent ray is different from distance on the vertical direction between the second sensor unit and the horizontal plane of the emergent ray.

37. The device according to claim 35, further comprising an adjusting unit disposed between the first sensor unit and the second sensor unit for dramatically adjusting a horizontal distance between the first sensor unit and the second sensor unit.

38. The device according to claim 27, wherein the sensor unit obtaining a first relative distance between the object and the light source at a first time point, obtaining a second relative distance between the object and the light source at a second time point, and obtaining movement of the object between the first time point and the second time point according to the first relative distance and the second relative distance.

39. The device according to claim 27, further comprising a transmission unit electrically connected to the sensing unit, the transmission unit being configured to transmit sensed images to a host having a signal connection to the device and to convert the relative distance between the object and the light source to a cursor display.

40. The device according to claim 27, wherein the plane light defines a sensing area on a real touch plane or on a stereoscopic operation plane.