Sensing system and method for obtaining location of pointer thereof

• US 8,131,502 B2
• Filed: 08/31/2009
• Issued: 03/06/2012
• Est. Priority Date: 10/10/2008
• Status: Active Grant

• Current Assignee: PixArt Imaging Incorporated
• Original Assignee: PixArt Imaging Incorporated
• Inventors: Su, Tzung-Min, Lin, Cho-Yi, Chen, Hsin-Chia, Lin, Chih-Hsin, Chao, Tzu-Yi
• Primary Examiner(s): Bui, Bryan
• Application Number:
  US12/550,681
• Publication Number:
  US 20100094584A1
• Time in Patent Office: 918 Days
• Field of Search: 702150-152, 345/157, 345/173, 345/174, 178/18.09
• US Class Current: 702/151
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen

Abstract

In a sensing system and a method for obtaining a location of a pointer, the sensing system includes a sensing area, a reflective mirror, a first image sensor and a second image sensor. The reflective mirror is configured for generating a mirror image of the sensing area. The sensing system utilizes the above two image sensors to sense the pointer disposed in the sensing area and a mirror image of the pointer for obtaining two coordinate values. And then the sensing system endues each of the two coordinate values with a weighting factor for calculating the location of the pointer.

Claims

1. A sensing system, comprising:

a sensing area;

a reflective mirror configured for generating mirror images of the sensing area;

a first image sensor;

a second image sensor, the second image sensor and the first image sensor being both configured for sensing images of the sensing area, and at least one of the first image sensor and the second image sensor having a sensing range covering all of the sensing area;

at least one light-emitting element, disposed on a boundary of the sensing area for emitting light towards the sensing area, the said at least one light-emitting element being mirrored by the reflective mirror so as to generate the mirror images corresponding to the said at least one light-emitting element; and

a processor, wherein when a pointer approaches the sensing area, the processor calculates a first coordinate value of the pointer according to the pointer and a mirror image of the pointer which are sensed by the first image sensor and endues the first coordinate value with a first weighting factor, and the processor also calculates a second coordinate value of the pointer according to the pointer and the mirror image of the pointer which are sensed by the second image sensor and endues the second coordinate value with a second weighting factor, such that the processor could calculate the location of the pointer according to the first coordinate value, the first weighting factor, the second coordinate value and the second weighting factor.

2. The sensing system as claimed in claim 1, wherein the processor regards the sensing area as a first area and divides the first area into a plurality of sub-areas to endue each of the sub-areas with a weighting factor in relation to the first image sensor, after the processor calculates the first coordinate value, the processor designates a weighting factor of a sub-area of the first area where the pointer is located as the first weighting factor;

the processor regards the sensing area as a second area and divides the second area into a plurality of sub-areas to endue each of the sub-areas with a weighting factor in relation to the second image sensor, after the processor calculates the second coordinate value, the processor designates a weighting factor of a sub-area of the first area where the pointer is located as the second weighting factor.

3. The sensing system as claimed in claim 1, wherein the processor comprises:

a first sub-processor configured for calculating the first coordinate value according to the pointer and the mirror image of the pointer which are sensed by the first image sensor and enduing the first coordinate value with the first weighting factor;

a second sub-processor configured for calculating the second coordinate value according to the pointer and the mirror image of the pointer which are sensed by the second image sensor and enduing the second coordinate value with the second weighting factor; and

a third sub-processor configured for calculating the location of the pointer according to the first coordinate value, the first weighting factor, the second coordinate value and the second weighting factor.

4. The sensing system as claimed in claim 3, wherein the first sub-processor regards the sensing area as a first area and divides the first area into a plurality of sub-areas to endue each of the sub-areas with a weighting factor in relation to the first image sensor, after the first sub-processor calculates the first coordinate value, the first sub-processor designates a weighting factor of a sub-area of the first area where the pointer is located as the first weighting factor;

the second sub-processor regards the sensing area as a second area and divides the second area into a plurality of sub-areas to endue each of the sub-areas with a weighting factor in relation to the second image sensor, after the second sub-processor calculates the second coordinate value, the second sub-processor designates a weighting factor of a sub-area of the second area where the pointer is located as the second weighting factor.

5. The sensing system as claimed in claim 1, wherein the sensing area is quadrangular and has a first boundary, a second boundary, a third boundary and a fourth boundary which are connected in order, the reflective mirror is disposed on the first boundary, the first image sensor is disposed at a corner at which the third boundary and the fourth boundary intersect, and the second image sensor is disposed at a corner at which the second boundary and the third boundary intersect.

6. The sensing system as claimed in claim 5, further comprising a first light-emitting element and a second light-emitting element, wherein the first light-emitting element and the second light-emitting element are disposed on the fourth boundary and the second boundary respectively and are configured for emitting light towards the sensing area, and the first light-emitting element and the second light-emitting element are mirrored by the reflective mirror so as to generate mirror images corresponding to the two light-emitting elements.

7. The sensing system as claimed in claim 5, further comprising a first light-reflecting element and a second light-reflecting element, wherein the first light-reflecting element and the second light-reflecting element are disposed on the fourth boundary and the second boundary respectively, and are configured for reflecting light towards the sensing area and not generating mirror images of the sensing area, and the first light-reflecting element and the second light-reflecting element are mirrored by the reflective mirror so as to generate mirror images corresponding to the two light-emitting elements.

8. The sensing system as claimed in claim 7, wherein each of the first light-reflecting element and the second light-reflecting element has a face facing the sensing area, the face has a reflective material, and the reflective material is a retro-reflective material.

9. The sensing system as claimed in claim 1, wherein each of the first image sensor and the second image sensor comprises an infrared illumination device.

10. The sensing system as claimed in claim 8, wherein the infrared illumination device comprises an infrared light-emitting diode.

11. The sensing system as claimed in claim 8, wherein each of the first image sensor and the second image sensor further comprises an infrared filter device configured for only allowing infrared light to pass therethrough, and each of the first image sensor and the second image sensor obtains the image of the sensing area via the infrared filter device.

12. A sensing system, comprising:

a sensing area;

a reflective mirror configured for generating mirror images of the sensing area;

at least one light-emitting element, disposed on a boundary of the sensing area for emitting light towards the sensing area, the said at least one light-emitting element being mirrored by the reflective mirror so as to generate the mirror images corresponding to the said at least one light-emitting element;

a first image sensor;

a second image sensor, the second image sensor and the first image sensor being both configured for sensing images of the sensing area, and at least one of the first image sensor and the second image sensor having a sensing range covering all of the sensing area;

a first processor, wherein when a pointer approaches the sensing area, the first processor calculates a first coordinate value of the pointer according to the pointer and a mirror image of the pointer which are sensed by the first image sensor and endues the first coordinate value with a first weighting factor; and

a second processor configured for receiving the first coordinate value and the first weighting factor, and determining whether to employ the second image sensor to sense the pointer and the mirror image of the pointer according to the first weighting factor for calculating the location of the pointer.

13. The sensing system as claimed in claim 12, wherein when the second processor determines to employ the second image sensor, the second processor calculates a second coordinate value of the pointer according to the pointer and the mirror image of the pointer which are sensed by the second image sensor and endues the second coordinate value with a second weighting factor, such that the second processor could calculate the location of the pointer according to the first coordinate value, the first weighting factor, the second coordinate value and the second weighting factor.

14. The sensing system as claimed in claim 13, wherein the first processor regards the sensing area as a first area and divides the first area into a plurality of sub-areas to endue each of the sub-areas with a weighting factor in relation to the first image sensor, after the first processor calculates the first coordinate value, the first processor designates a weighting factor of a sub-area of the first area where the pointer is located as the first weighting factor;

the second processor regards the sensing area as a second area and divides the second area into a plurality of sub-areas to endue each of the sub-areas with a weighting factor in relation to the second image sensor, after the second processor calculates the second coordinate value, the second processor designates a weighting factor of a sub-area of the second area where the pointer is located as the second weighting factor.

15. The sensing system as claimed in claim 12, wherein when the second processor determines to employ the second image sensor, the second processor calculates a second coordinate value of the pointer according to the pointer and the mirror image of the pointer which are sensed by the second image sensor, and regards the second coordinate value as the location of the pointer.

16. The sensing system as claimed in claim 15, wherein the first processor regards the sensing area as a first area and divides the first area into a plurality of sub-areas to endue each of the sub-areas with a weighting factor in relation to the first image sensor, after the first processor calculates the first coordinate value, the first processor designates a weighting factor of a sub-area of the first area where the pointer is located as the first weighting factor.

17. The sensing system as claimed in claim 12, wherein when the second processor determines not to employ the second image sensor, the second processor regards the first coordinate value as the location of the pointer.

18. The sensing system as claimed in claim 17, wherein the first processor regards the sensing area as a first area and divides the first area into a plurality of sub-areas to endue each of the sub-areas with a weighting factor in relation to the first image sensor, after the first processor calculates the first coordinate value, the first processor regards a weighting factor of a sub-area of the first area where the pointer is located as the first weighting factor.

19. The sensing system as claimed in claim 12, wherein the sensing area is quadrangular and has a first boundary, a second boundary, a third boundary and a fourth boundary which are connected in order, the reflective mirror is disposed on the first boundary, the first image sensor is disposed at a corner at which the third boundary and the fourth boundary intersect, and the second image sensor is disposed at a corner at which the second boundary and the third boundary intersect.

20. The sensing system as claimed in claim 19, further comprising a first light-emitting element and a second light-emitting element, wherein the first light-emitting element and the second light-emitting element are disposed on the fourth boundary and the second boundary respectively and are configured for emitting light towards the sensing area, and the first light-emitting element and the second light-emitting element are mirrored by the reflective mirror so as to generate mirror images corresponding to the two light-emitting elements.

21. The sensing system as claimed in claim 19, further comprising a first light-reflecting element and a second light-reflecting element, wherein the first light-reflecting element and the second light-reflecting element are disposed on the fourth boundary and the second boundary respectively, and are configured for reflecting light towards the sensing area and not generating mirror images of the sensing area, and the first light-reflecting element and the second light-reflecting element are mirrored by the reflective mirror so as to generate mirror images corresponding to the two light-emitting elements.

22. The sensing system as claimed in claim 21, wherein each of the first light-reflecting element and the second light-reflecting element has a face facing the sensing area, the face has a reflective material, and the reflective material is a retro-reflective material.

23. The sensing system as claimed in claim 12, wherein each of the first image sensor and the second image sensor comprises an infrared illumination device.

24. The sensing system as claimed in claim 23, wherein the infrared illumination device comprises an infrared light-emitting diode.

25. The sensing system as claimed in claim 23, wherein each of the first image sensor and the second image sensor further comprises an infrared filter device configured for only allowing infrared light to pass therethrough, and each of the first image sensor and the second image sensor obtains an image of the sensing area via the infrared filter device.

26. A method for obtaining a location of a pointer, the method being adapted for a sensing system, the sensing system comprising a sensing area, a reflective mirror, a first image sensor and a second image sensor, the reflective mirror being configured for generating a mirror image of the sensing area, the first image sensor and the second image sensor being both configured for sensing images of the sensing area, and at least one of the first image sensor and the second image sensor having a sensing range covering all of the sensing area, the method comprising:

calculating a first coordinate value of the pointer according to the pointer and a mirror image of the pointer which are sensed by the first image sensor and enduing the first coordinate value with a first weighting factor;

calculating a second coordinate value of the pointer according to the pointer and the mirror image of the pointer which are sensed by the second image sensor and enduing the second coordinate value with a second weighting factor; and

calculating the location of the pointer according to the first coordinate value, the first weighting factor, the second coordinate value and the second weighting factor.

27. The method as claimed in claim 26, wherein the steps of generating the first weighting factor in the method comprises to regard the sensing area as a first area, to divide the first area into a plurality of sub-areas to endue each of the sub-areas with a weighting factor in relation to the first image sensor, to designate a weighting factor of a sub-area of the first area where the pointer is located as the first weighting factor after calculating the first coordinate value;

the steps of generating the second weighting factor in the method comprises to regard the sensing area as a second area, to divide the second area into a plurality of sub-areas to endue each of the sub-areas with a weighting factor in relation to the second image sensor, to designate a weighting factor of a sub-area of the second area where the pointer is located as the second weighting factor after calculating the second coordinate value.

28. A method for obtaining a location of a pointer, the method being adapted for a sensing system, the sensing system comprising a sensing area, a reflective mirror, a first image sensor and a second image sensor, the reflective mirror being configured for generating a mirror image of the sensing area, the first image sensor and the second image sensor being both configured for sensing images of the sensing area, and at least one of the first image sensor and the second image sensor having a sensing range covering all of the sensing area, the method comprising:

calculating a first coordinate value of the pointer according to the pointer and a mirror image of the pointer which are sensed by the first image sensor and enduing the first coordinate value with a first weighting factor; and

determining whether to employ the second image sensor to sense the pointer and the mirror image of the pointer according to the first weighting factor for calculating the location of the pointer.

29. The method as claimed in claim 28, wherein when determining to employ the second image sensor, a second coordinate value of the pointer is calculated according to the pointer and the mirror image of the pointer which are sensed by the second image sensor and the second coordinate value is endued with a second weighting factor, such that the location of the pointer could be calculated according to the first coordinate value, the first weighting factor, the second coordinate value and the second weighting factor.

30. The method as claimed in claim 29, wherein the steps of generating the first weighting factor in the method comprises to regard the sensing area as a first area, to divide the first area into a plurality of sub-areas to endue each of the sub-areas with a weighting factor in relation to the first image sensor, to designate a weighting factor of a sub-area of the first area where the pointer is located as the first weighting factor after calculating the first coordinate value;

the steps of generating the second weighting factor in the method comprises to regard the sensing area as a second area, to divide the second area into a plurality of sub-areas to endue each of the sub-areas with a weighting factor in relation to the second image sensor, to designate a weighting factor of a sub-area of the second area where the pointer is located as the second weighting factor after calculating the second coordinate value.

31. The method as claimed in claim 28, wherein when determining to employ the second image sensor, a second coordinate value of the pointer is calculated according to the pointer and the mirror image of the pointer which are sensed by the second image sensor, and the second coordinate value is regarded as the location of the pointer.

32. The method as claimed in claim 31, wherein the steps of generating the first weighting factor in the method comprises to regard the sensing area as a first area, to divide the first area into a plurality of sub-areas to endue each of the sub-areas with a weighting factor in relation to the first image sensor, to designate a weighting value of a sub-area of the first area where the pointer is located as the first weighting factor after calculating the first coordinate value.

33. The method as claimed in claim 28, wherein when determining not to employ the second image sensor, the first coordinate value is regarded as the location of the pointer.

34. The method as claimed in claim 33, wherein the steps of generating the first weighting factor in the method comprises to regard the sensing area as a first area, to divide the first area into a plurality of sub-areas to endue each of the sub-areas with a weighting factor in relation to the first image sensor, to designate a weighting factor of a sub-area of the first area where the pointer is located as the first weighting factor after calculating the first coordinate value.

35. A sensing system, comprising:

a sensing area;

a reflective mirror configured for generating mirror images of the sensing area;

a first image sensor;

a second image sensor, the second image sensor and the first image sensor being both configured for sensing images of the sensing area, and at least one of the first image sensor and the second image sensor having a sensing range covering all of the sensing area, wherein each of the first image sensor and the second image sensor comprises an infrared illumination device; and

a processor, wherein when a pointer approaches the sensing area, the processor calculates a first coordinate value of the pointer according to the pointer and a mirror image of the pointer which are sensed by the first image sensor and endues the first coordinate value with a first weighting factor, and the processor also calculates a second coordinate value of the pointer according to the pointer and the mirror image of the pointer which are sensed by the second image sensor and endues the second coordinate value with a second weighting factor, such that the processor could calculate the location of the pointer according to the first coordinate value, the first weighting factor, the second coordinate value and the second weighting factor.

36. The sensing system as claimed in claim 35, wherein the processor regards the sensing area as a first area and divides the first area into a plurality of sub-areas to endue each of the sub-areas with a weighting factor in relation to the first image sensor, after the processor calculates the first coordinate value, the processor designates a weighting factor of a sub-area of the first area where the pointer is located as the first weighting factor;

the processor regards the sensing area as a second area and divides the second area into a plurality of sub-areas to endue each of the sub-areas with a weighting factor in relation to the second image sensor, after the processor calculates the second coordinate value, the processor designates a weighting factor of a sub-area of the first area where the pointer is located as the second weighting factor.

37. The sensing system as claimed in claim 35, wherein the processor comprises:

a first sub-processor configured for calculating the first coordinate value according to the pointer and the mirror image of the pointer which are sensed by the first image sensor and enduing the first coordinate value with the first weighting factor;

a second sub-processor configured for calculating the second coordinate value according to the pointer and the mirror image of the pointer which are sensed by the second image sensor and enduing the second coordinate value with the second weighting factor; and

a third sub-processor configured for calculating the location of the pointer according to the first coordinate value, the first weighting factor, the second coordinate value and the second weighting factor.

38. The sensing system as claimed in claim 37, wherein the first sub-processor regards the sensing area as a first area and divides the first area into a plurality of sub-areas to endue each of the sub-areas with a weighting factor in relation to the first image sensor, after the first sub-processor calculates the first coordinate value, the first sub-processor designates a weighting factor of a sub-area of the first area where the pointer is located as the first weighting factor;

the second sub-processor regards the sensing area as a second area and divides the second area into a plurality of sub-areas to endue each of the sub-areas with a weighting factor in relation to the second image sensor, after the second sub-processor calculates the second coordinate value, the second sub-processor designates a weighting factor of a sub-area of the second area where the pointer is located as the second weighting factor.

39. The sensing system as claimed in claim 35, wherein the sensing area is quadrangular and has a first boundary, a second boundary, a third boundary and a fourth boundary which are connected in order, the reflective mirror is disposed on the first boundary, the first image sensor is disposed at a corner at which the third boundary and the fourth boundary intersect, and the second image sensor is disposed at a corner at which the second boundary and the third boundary intersect.

40. The sensing system as claimed in claim 39, further comprising a first light-emitting element and a second light-emitting element, wherein the first light-emitting element and the second light-emitting element are disposed on the fourth boundary and the second boundary respectively and are configured for emitting light towards the sensing area, and the first light-emitting element and the second light-emitting element are mirrored by the reflective mirror so as to generate mirror images corresponding to the two light-emitting elements.

41. The sensing system as claimed in claim 39, further comprising a first light-reflecting element and a second light-reflecting element, wherein the first light-reflecting element and the second light-reflecting element are disposed on the fourth boundary and the second boundary respectively, and are configured for reflecting light towards the sensing area and not generating mirror images of the sensing area, and the first light-reflecting element and the second light-reflecting element are mirrored by the reflective mirror so as to generate mirror images corresponding to the two light-emitting elements.

42. The sensing system as claimed in claim 41, wherein each of the first light-reflecting element and the second light-reflecting element has a face facing the sensing area, the face has a reflective material, and the reflective material is a retro-reflective material.

43. The sensing system as claimed in claim 35, wherein the infrared illumination device comprises an infrared light-emitting diode.

44. The sensing system as claimed in claim 35, wherein each of the first image sensor and the second image sensor further comprises an infrared filter device configured for only allowing infrared light to pass therethrough, and each of the first image sensor and the second image sensor obtains the image of the sensing area via the infrared filter device.

45. A sensing system, comprising:

a sensing area;

a reflective mirror configured for generating mirror images of the sensing area;

a first image sensor;

a second image sensor, the second image sensor and the first image sensor being both configured for sensing images of the sensing area, and at least one of the first image sensor and the second image sensor having a sensing range covering all of the sensing area, wherein each of the first image sensor and the second image sensor comprises an infrared illumination device;

a first processor, wherein when a pointer approaches the sensing area, the first processor calculates a first coordinate value of the pointer according to the pointer and a mirror image of the pointer which are sensed by the first image sensor and endues the first coordinate value with a first weighting factor; and

a second processor configured for receiving the first coordinate value and the first weighting factor, and determining whether to employ the second image sensor to sense the pointer and the mirror image of the pointer according to the first weighting factor for calculating the location of the pointer.

46. The sensing system as claimed in claim 45, wherein when the second processor determines to employ the second image sensor, the second processor calculates a second coordinate value of the pointer according to the pointer and the mirror image of the pointer which are sensed by the second image sensor and endues the second coordinate value with a second weighting factor, such that the second processor could calculate the location of the pointer according to the first coordinate value, the first weighting factor, the second coordinate value and the second weighting factor.

47. The sensing system as claimed in claim 46, wherein the first processor regards the sensing area as a first area and divides the first area into a plurality of sub-areas to endue each of the sub-areas with a weighting factor in relation to the first image sensor, after the first processor calculates the first coordinate value, the first processor designates a weighting factor of a sub-area of the first area where the pointer is located as the first weighting factor;

the second processor regards the sensing area as a second area and divides the second area into a plurality of sub-areas to endue each of the sub-areas with a weighting factor in relation to the second image sensor, after the second processor calculates the second coordinate value, the second processor designates a weighting factor of a sub-area of the second area where the pointer is located as the second weighting factor.

48. The sensing system as claimed in claim 45, wherein when the second processor determines to employ the second image sensor, the second processor calculates a second coordinate value of the pointer according to the pointer and the mirror image of the pointer which are sensed by the second image sensor, and regards the second coordinate value as the location of the pointer.

49. The sensing system as claimed in claim 48, wherein the first processor regards the sensing area as a first area and divides the first area into a plurality of sub-areas to endue each of the sub-areas with a weighting factor in relation to the first image sensor, after the first processor calculates the first coordinate value, the first processor designates a weighting factor of a sub-area of the first area where the pointer is located as the first weighting factor.

50. The sensing system as claimed in claim 45, wherein when the second processor determines not to employ the second image sensor, the second processor regards the first coordinate value as the location of the pointer.

51. The sensing system as claimed in claim 50, wherein the first processor regards the sensing area as a first area and divides the first area into a plurality of sub-areas to endue each of the sub-areas with a weighting factor in relation to the first image sensor, after the first processor calculates the first coordinate value, the first processor regards a weighting factor of a sub-area of the first area where the pointer is located as the first weighting factor.

52. The sensing system as claimed in claim 45, wherein the sensing area is quadrangular and has a first boundary, a second boundary, a third boundary and a fourth boundary which are connected in order, the reflective mirror is disposed on the first boundary, the first image sensor is disposed at a corner at which the third boundary and the fourth boundary intersect, and the second image sensor is disposed at a corner at which the second boundary and the third boundary intersect.

53. The sensing system as claimed in claim 52, further comprising a first light-emitting element and a second light-emitting element, wherein the first light-emitting element and the second light-emitting element are disposed on the fourth boundary and the second boundary respectively and are configured for emitting light towards the sensing area, and the first light-emitting element and the second light-emitting element are mirrored by the reflective mirror so as to generate mirror images corresponding to the two light-emitting elements.

54. The sensing system as claimed in claim 52, further comprising a first light-reflecting element and a second light-reflecting element, wherein the first light-reflecting element and the second light-reflecting element are disposed on the fourth boundary and the second boundary respectively, and are configured for reflecting light towards the sensing area and not generating mirror images of the sensing area, and the first light-reflecting element and the second light-reflecting element are mirrored by the reflective mirror so as to generate mirror images corresponding to the two light-emitting elements.

55. The sensing system as claimed in claim 54, wherein each of the first light-reflecting element and the second light-reflecting element has a face facing the sensing area, the face has a reflective material, and the reflective material is a retro-reflective material.

56. The sensing system as claimed in claim 45, wherein the infrared illumination device comprises an infrared light-emitting diode.

57. The sensing system as claimed in claim 45, wherein each of the first image sensor and the second image sensor further comprises an infrared filter device configured for only allowing infrared light to pass therethrough, and each of the first image sensor and the second image sensor obtains an image of the sensing area via the infrared filter device.