Optical detection system, device, and method utilizing optical matching

• US 6,927,758 B1
• Filed: 06/29/2001
• Issued: 08/09/2005
• Est. Priority Date: 06/05/1997
• Status: Expired due to Term

• Current Assignee: Logitech Europe S A (Logitech International SA)
• Original Assignee: Logitech Europe S A (Logitech International SA)
• Inventors: Nussbaum, Philippe J., Schnell, Urban G., Piot, Julien
• Primary Examiner(s): Liang, Regina
• Assistant Examiner(s): Nguyen, Jennifer T.
• Application Number:
  US09/895,749
• Time in Patent Office: 1,502 Days
• Field of Search: 345/158, 345163-167, 250/208.1, 250/234, 250/235, 250/221, 250/208.5, 250/214.1, 250/215, 356/375, 356/376
• 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

Abstract

An optical detection system and method detects movement of an optical pointing device in a data processing environment. The system works with any surface than can diffusely scatter a collimated beam from a coherent light source. Specifically, the system comprises a coherent light source and an optical sensing assembly. The optical sensing assembly comprises a plurality of photosensor arrays and a plurality of optical elements. Each photosensor array includes pixels of a particular size and shape. Each optical element has an artificially limited aperture and is associated, through optical matching, with a respective photosensor array. The coherent light source generates a collimated beam that is diffusely reflected off of the surface. The optical sensing assembly receives the diffusely reflected, or scattered, collimated beam and passes it through the artificially limited apertures of the optical elements to the associated corresponding photosensor array. Passing the scattered light through the optical elements generates speckle images that appear on the pixels, of the photosensor arrays. Based on the pixel shape, a pixel value associated with the speckle image provides a speckle image data signal. When there is translation of the pointing device, a new set of speckle images, each reassembling to a translated version of the previous speckle image, are generated and another speckle image data signal is generated. The new and the previous speckle image data signals are then used in a motion detection analysis to determine the points of the two data signals that give a displacement value.

Claims

1. In an optical detection system housing a coherent light source for illuminating a surface, and an optical sensing assembly comprising at least one photosensitive array and at least one optical element, a method for detecting movement comprising:

generating an illumination spot on the surface by lighting the surface with a coherent light beam from the coherent light source, the illumination spot providing optically back-scattered light off the surface;

arranging each optical element to pass an image of the illumination spot onto each photosensor array associated with an optical element, the photosensor array having a plurality of pixels; and

generating at least one image data signal from each photosensor array in response to the image on the plurality of pixels of that photosensor array, each image data signal comprising at least one image data point;

storing a first image data signal and a second image data signal, the first image data signal comprises a first substantially random image data signal and the second image data signal comprises a second substantially random image data signal; and

measuring similarility of images through the first image data signal and the second image data signal to obtain a displacement value, the displacement value indicative of detected movement, the similarity of the first image data signal to the second image data signal is measured at a multiple of a shift value, the first image data signal being shifted by a predetermined shift value prior to the measurement.

2. The method of claim 1, wherein the first image data signal is stored in a first portion of a memory unit and the second image data signal is stored in a second portion of the memory unit.

3. The method of claim 1, wherein the first image data signal is stored in a first portion of a memory unit at a start of operation of the optical detection system and the second image data signal is stored in a second portion of a memory unit for each set of measurements of the similarity of images.

4. The method of claim 1, wherein the second image data signal is substantially a shifted version of the first image data signal.

5. The method of claim 1, wherein the first image data signal comprises a first speckle image data signal and the second image data signal comprises a second speckle image data signal.

6. The method of claim 5, wherein the speckle image associated with at least one of the first speckle image data signal and the second speckle image data signal comprises speckles of a dimension greater than or equal to a pixel dimension.

7. The method of claim 1, wherein the similarity of at least two image data signals is based on each image data comprising a set and is measured at a multiple of a shift value, each set comprising a high resolution and a low resolution image data signal, and the image data signal in a first set being shifted by a predetermined shift value prior to the measurement.

8. The method of claim 1, wherein measuring the similarity is performed through an application of a cross correlation function.

9. The method of claim 8, wherein performing the cross correlation function further comprises:

multiplying the first image data signal and the second image data signal and summing results of each multiplication operation over each data point.

10. The method of claim 9, wherein the cross correlation of the first image data signal to the second image data signal is measured at a multiplicity of a shift value, the first image data signal being shifted by a predetermined shift value before the cross correlation is measured.

11. The method of claim 10, wherein the displacement value comprises identifying the shift to apply to the first image data signal that results in a substantial cross correlation between the first image shifted by the displacement value and the second image.

12. The method of claim 1, wherein the displacement value comprises identifying a shift to apply to the first image data signal that results in a substantial similarity between the first image shifted by the displacement value and the second image.

13. The method of claim 1, wherein the first image data signal is replaced by the second image data when a displacement value comprises a predetermined value.

14. The method of claim 1, wherein the at least one optical element comprises a lens.

15. The method of claim 1, wherein the at least one optical element comprises a lens and an aperture.

16. The method of claim 1, wherein the coherent light beam from the coherent light source comprises a collimated beam.

17. The method of claim 16, wherein the collimated beam produces the illumination spot on the surface.

18. The method of claim 1, wherein the light source comprises a laser diode.

19. The method of claim 1, wherein the back-scattered light from the surface, passes through the at least one optical element to generate an image of the illumination spot on the pixels of the at least one photosensor array.

20. The method of claim 19, wherein the image is focused on the photosensor array.

21. The method of claim 1, wherein the back-scattered light from the surface, passes through the at least one optical element to generate an image of the illumination spot that is less than or equal to a size of the photosensor array.

22. In an optical detection system housing a coherent light source for illuminating a surface, and an optical sensing assembly comprising at least one photosensitive array and at least one optical element, a method for detecting movement comprising:

generating an illumination spot on the surface by lighting the surface with a coherent light beam from the coherent light source, the illumination spot providing optically back-scattered light off the surface;

arranging each optical element to pass an image of the illumination spot onto each photosensor array associated with an optical element, the photosensor array having a plurality of pixels; and

generating at least one image data signal from each photosensor array in response to the image on the plurality of pixels of that photosensor array, each image data signal comprising at least one image data point;

storing a first image data signal and a second image data signal, the second image data signal is substantially a shifted version of the first image data signal; and

measuring similarility of images through the first image data signal and the second image data signal to obtain a displacement value, the displacement value indicative of detected movement, the similarity of the first image data signal to the second image data signal is measured at a multiple of a shift value, the first image data signal being shifted by a predetermined shift value prior to the measurement.

23. The method of claim 22, wherein the first image data signal is stored in a first portion of a memory unit and the second image data signal is stored in a second portion of the memory unit.

24. The method of claim 22, wherein the first image data signal is stored in a first portion of a memory unit at a start of operation of the optical detection system and the second image data signal is stored in a second portion of a memory unit for each set of measurements of the similarity of images.

25. The method of claim 22, wherein the first image data signal comprises a first substantially random image data signal and the second image data signal comprises a second substantially random image data signal.

26. The method of claim 22, wherein the similarity of the first image data signal to the second image data signal is measured at a multiple of a shift value, the second image data signal being shifted by a predetermined shift value prior to the measurement.

27. The method of claim 22, wherein the similarity of the first image data signal to the second image data signal is measured at a predetermined multiple of a shift value, the second image data signal being shifted by a predetermined shift value prior to the measurement.

28. The method of claim 22, wherein the similarity of at least two image data signals is based on each image data comprising a set and is measured at a multiple of a shift value, each set comprising a high resolution and a low resolution image data signal, and the image data signal in a first set being shifted by a predetermined shift value prior to the measurement.

29. The method of claim 22, wherein measuring the similarity is performed through an application of a cross correlation function.

30. The method of claim 29, wherein performing the cross correlation function further comprises:

multiplying the first image data signal and the second image data signal and summing results of each multiplication operation over each data point.

31. The method of claim 30, wherein the cross correlation of the first image data signal to the second image data signal is measured at a multiplicity of a shift value, the first image data signal being shifted by a predetermined shift value before the cross correlation is measured.

32. The method of claim 31, wherein the displacement value comprises identifying the shift to apply to the first image data signal that results in a substantial cross correlation between the first image shifted by the displacement value and the second image.

33. The method of claim 22, wherein the displacement value comprises identifying a shift to apply to the first image data signal that results in a substantial similarity between the first image shifted by the displacement value and the second image.

34. The method of claim 22, wherein the first image data signal is replaced by the second image data when a displacement value comprises a predetermined value.

35. The method of claim 22, wherein the at least one optical element comprises a lens.

36. The method of claim 22, wherein the at least one optical element comprises a lens and an aperture.

37. The method of claim 22, wherein the coherent light beam from the coherent light source comprises a collimated beam.

38. The method of claim 37, wherein the collimated beam produces the illumination spot on the surface.

39. The method of claim 22, wherein the light source comprises a laser diode.

40. The method of claim 22, wherein the back-scattered light from the surface, passes through the at least one optical element to generate an image of the illumination spot on the pixels of the at least one photosensor array.

41. The method of claim 22, wherein the back-scattered light from the surface, passes through the at least one optical element to generate an image of the illumination spot that is less than or equal to a size of the photosensor array.

42. The method of claim 41, wherein the image is focused on the photosensor array.

43. The method of claim 22, wherein the first image data signal comprises a first speckle image data signal and the second image data signal comprises a second speckle image data signal.

44. The method of claim 43, wherein the speckle image associated with at least one of the first speckle image data signal and the second speckle image data signal comprises speckles of a dimension greater than or equal to a pixel dimension.

45. In an optical detection system housing a coherent light source for illuminating a surface, and an optical sensing assembly comprising at least one photosensitive array and at least one optical element, a method for detecting movement comprising:

generating an illumination spot on the surface by lighting the surface with a coherent light beam from the coherent light source, the illumination spot providing optically back-scattered light off the surface;

arranging each optical element to pass an image of the illumination spot onto each photosensor array associated with an optical element, the photosensor array having a plurality of pixels; and

generating at least one image data signal from each photosensor array in response to the image on the plurality of pixels of that photosensor array, each image data signal comprising at least one image data point;

storing a first image data signal and a second image data signal, the first image data signal comprises a first speckle image data signal and the second image data signal comprises a second speckle image data signal; and

measuring similarility of images through the first image data signal and the second image data signal to obtain a displacement value, the displacement value indicative of detected movement, the similarity of the first image data signal to the second image data signal measured at a multiple of a shift value, the first image data signal being shifted by a predetermined shift value prior to the measurement.

46. The method of claim 45, wherein the first speckle image data signal is stored in a first portion of a memory unit and the second speckle image data signal is stored in a second portion of the memory unit.

47. The method of claim 45, wherein the first speckle image data signal is stored in a first portion of a memory unit at a start of operation of the optical detection system and the second speckle image data signal is stored in a second portion of a memory unit for each set of measurements of the similarity of images.

48. The method of claim 45, wherein the first speckle image data signal comprises a first substantially random image data signal and the second speckle image data signal comprises a second substantially random image data signal.

49. The method of claim 45, wherein the similarity of the first speckle image data signal to the second speckle image data signal is measured at a multiple of a shift value, the first speckle image data signal being shifted by a predetermined shift value prior to the measurement.

50. The method of claim 49, wherein the similarity of the first speckle image data signal to the second speckle image data signal is measured at a predetermined multiple of a shift value, the first speckle image data signal being shifted by a predetermined shift value prior to the measurement.

51. The method of claim 45, wherein the similarity of at least two speckle image data signals is measured at a multiple of a shift value, each set comprising a high resolution and a low resolution image data signal, and the speckle image data signal in the first set being shifted by a predetermined shift value prior to the measurement.

52. The method of claim 45, wherein measuring the similarity is performed through an application of a cross correlation function.

53. The method of claim 52, wherein performing the cross correlation function further comprises:

multiplying the first image data signal and the second image data signal and summing results of each multiplication operation over each data point.

54. The method of claim 53, wherein the cross correlation of the first speckle image data signal to the second speckle image data signal is measured at a multiplicity of a shift value, the first speckle image data signal being shifted by a predetermined shift value before the cross correlation is measured.

55. The method of claim 54, wherein the displacement value comprises identifying the shift to apply to the first image data signal that results in a substantial cross correlation between the first speckle image shifted by the displacement value and the second speckle image.

56. The method of claim 55, wherein the second speckle image data signal is substantially a shifted version of the first speckle image data signal.

57. The method of claim 45, wherein the displacement value comprises identifying a shift to apply to the first speckle image data signal that results in a substantial similarity between the first speckle image shifted by the displacement value and the second speckle image.

58. The method of claim 45, wherein the first speckle image data signal is replaced by the second speckle image data when a displacement value comprises a predetermined value.

59. The method of claim 45, wherein the at least one optical element comprises a lens.

60. The method of claim 45 wherein the at least one optical element comprises a lens and an aperture.

61. The method of claim 45, wherein the coherent light beam from the coherent light source comprises a collimated beam.

62. The method of claim 61, wherein the collimated beam produces the illumination spot on the surface.

63. The method of claim 45, wherein the light source comprises a laser diode.

64. The method of claim 45, wherein the back-scattered light from the surface, passes through the at least one optical element to generate an image of the illumination spot on the pixels of the at least one photosensor array.

65. The method of claim 64, wherein the image is focused on the photosensor array.

66. The method of claim 45, wherein the back-scattered light from the surface, passes through the at least one optical element to generate an image of the illumination spot that is less than or equal to a size of the photosensor array.

67. The method of claim 45, wherein a speckle image associated with at least one of the first speckle image data signal and the second speckle image data signal comprises speckles of a dimension greater than or equal to a pixel dimension.

68. The method of claim 45, wherein the second image data signal is substantially a shifted version of the first image data signal.

71. The method of claim 45, wherein the similarity of the first image data signal to the second image data signal is measured at a multiple of a shift value, the first image data signal being shifted by a predetermined shift value prior to the measurement.

72. The method of claim 45, wherein the similarity of the first image data signal to the second image data signal is measured at a predetermined multiple of a shift value, the second image data signal being shifted by a shift value prior to the measurement.

73. The method of claim 45, wherein the similarity of the first image data signal to the second image data signal is measured at a multiple of a shift value, the second image data signal being shifted by a predetermined shift value prior to the measurement.

69. The method of 45, wherein the first image data signal comprises a first speckle image data signal and the second image data signal comprises a second speckle image data signal.

70. The method of claim 69, wherein the speckle image associated with at least one of the first speckle image data signal and the second speckle image data signal comprises speckles of a dimension greater than or equal to a pixel dimension.

74. In an optical detection system housing a coherent light source for illuminating a surface, and an optical sensing assembly comprising at least one photosensitive array and at least one optical element, a method for detecting movement comprising:

generating an illumination spot on the surface by lighting the surface with a coherent light beam from the coherent light source, the illumination spot providing optically back-scattered light off the surface;

arranging each optical element to pass an image of the illumination spot onto each photosensor array associated with an optical element, the photosensor array having a plurality of pixels; and

generating at least one image data signal from each photosensor array in response to the image on the plurality of pixels of that photosensor array, each image data signal comprising at least one image data point;

storing a first image data signal in a first set and storing a second image data signal in a second set, each set comprising a high resolution and a low resolution image data signal, each image data signal representing a random image; and

measuring similarility of image data signals in the first set and the second set to obtain a displacement value, the displacement value indicative of detected movement, the similarity of at least two image data signals is measured at a multiple of a shift value, the image data signal in the first set being shifted by a predetermined shift value prior to the measurement.

75. The method of claim 74, wherein the first image data signal is stored in a first portion of a memory unit and the second image data signal is stored in a second portion of the memory unit.

76. The method of claim 74, wherein the first image data signal is stored in a first portion of a memory unit at a start of operation of the optical detection system and the second image data signal is stored in a second portion of a memory unit for each set of measurements of the similarity of images.

77. The method of claim 74, wherein measuring the similarity is performed through an application of a cross correlation function.

78. The method of claim 77, wherein performing the cross correlation function further comprises:

multiplying the first image data signal and the second image data signal and summing results of each multiplication operation over each data point.

79. The method of claim 78, wherein the cross correlation of the first image data signal to the second image data signal is measured at a multiplicity of a shift value, the first image data signal being shifted by a predetermined shift value before the cross correlation is measured.

80. The method of claim 79, wherein the displacement value comprises identifying the shift to apply to the first image data signal that results in a substantial cross correlation between the first image shifted by the displacement value and the second image.

81. The method of claim 74, wherein the displacement value comprises identifying a shift to apply to the first image data signal that results in a substantial similarity between the first image shifted by the displacement value and the second image.

82. The method of claim 74, wherein the first image data signal is replaced by the second image data when a displacement value comprises a predetermined value.

83. The method of claim 74, wherein the at least one optical element comprises a lens.

84. The method of claim 74, wherein the at least one optical element comprises a lens and an aperture.

85. The method of claim 74, wherein the coherent light beam from the coherent light source comprises a collimated beam.

86. The method of claim 85, wherein the collimated beam produces the illumination spot on the surface.

87. The method of claim 74, wherein the light source comprises a laser diode.

88. The method of claim 74, wherein the back-scattered light from the surface, passes through the at least one optical element to generate an image of the illumination spot on the pixels of the at least one photosensor array.

89. The method of claim 88, wherein the image is focused on the photosensor array.

90. The method of claim 74, wherein the back-scattered light from the surface, passes through the at least one optical element to generate an image of the illumination spot that is less than or equal to a size of the photosensor array.

91. In an optical detection system housing a coherent light source for illuminating a surface, and an optical sensing assembly comprising at least one photosensitive array and at least one optical element, a method for detecting movement comprising:

generating an illumination spot on the surface by lighting the surface with a coherent light beam from the coherent light source, the illumination spot providing optically back-scattered light off the surface;

arranging each optical element to pass an image of the illumination spot onto each photosensor array associated with an optical element, the photosensor array having a plurality of pixels; and

generating at least one image data signal from each photosensor array in response to the image on the plurality of pixels of that photosensor array, each image data signal comprising at least one image data point;

storing a first image data signal and a second image data signal; and

measuring similarility of images through the first image data signal and the second image data signal to obtain a displacement value, the displacement value indicative of detected movement, the similarity measured through application of a cross correlation function further comprising, multiplying the first image data signal and the second image data signal, and summing results of each multiplication operation over each data point.

92. The method of claim 91, wherein the cross correlation of the first image data signal to the second image data signal is measured at a multiplicity of a shift value, the first image data signal being shifted by a predetermined shift value before the cross correlation is measured.

93. The method of claim 92, wherein the displacement value comprises identifying the shift to apply to the first image data signal that results in a substantial cross correlation between the first image shifted by the displacement value and the second image.

94. The system of claim 93, wherein the first storage area comprises a first portion of a memory unit and the second storage area comprises a second portion of the memory unit.

95. The system of claim 93, wherein the first image data signal comprises a first substantially random image data signal and the second image data signal comprises a second substantially random image data signal.

96. The system of claim 95, wherein the comparison module comprises a cross correlation module.

97. The system of claim 96, wherein the similarity of one set to a plurality of at least two image data signals is measured at a multiple of a shift value, each set comprising a high resolution and a low resolution image data signal, and the image data signal in the first set being shifted by a predetermined shift value prior to the measurement.

98. The system of claim 96, wherein cross-correlation module applies the cross-correlation function on two sets of two image data signals, each set comprising a high resolution and a low resolution image data signals, and in each set, each of the image data signals being shifted at least a portion of a pixel on a photosensor array.

99. The system of claim 96, wherein the cross-correlation module is further configured to:

multiply the first image data signal and the second image data signal; and

sum results of each multiplication operation.

100. The system of claim 93, wherein the second image data signal is substantially a shifted version of the first image data signal.

101. The system of claim 93, wherein the first image data signal comprises a first speckle image data signal and the second image data signal comprises a second speckle image data signal.

102. The system of claim 101, wherein the speckle image associated with at least one of the first speckle image data signal and the second speckle image data signal comprises speckles of a dimension greater than or equal to a dimension of a pixel of the pixels.

103. The system of claim 93, wherein the first image data signal comprises a first randomly patterned image data signal and the second image data signal comprises a second randomly patterned image data signal.

104. The system of claim 93, wherein the displacement value comprises an argument of the cross-correlation function at function peaks.

105. The system of claim 93, wherein the first image data signal is replaced by the second image data when the displacement value comprises a predetermined value.

106. The system of claim 93, wherein the at least one optical element comprises a lens.

107. The system of claim 93, wherein the at least one optical element comprises a lens and an aperture.

108. The system of claim 93, wherein the coherent light beam from the coherent light source comprises a collimated beam.

109. The system of claim 108, wherein the collimated beam produces the illumination spot on the surface.

110. The system of claim 93, wherein the coherent light source comprises a laser diode.

111. The system of claim 93, wherein the back-scattered light from the surface, passes through the at least one optical element to generate an image of the illumination spot that is less than or equal to a size of the photosensor array.

112. The system of claims 93, wherein the photosensor array comprises a plurality of photodiode pixels.

113. The system of claim 93, wherein an image data point comprises a digital value representative of a pixel on the photosensor array.

114. An optical detection system to identify displacement, the system comprising:

a coherent light source configured to generate an illumination spot on a surface, the illumination spot providing optically back-scattered light off the surface;

at least one photosensitive array, each photosensor array having pixels;

at least one optical element, each optical element associated with a photosensitive array, each optical element configured to pass an image of the illumination spot onto its associated photosensor array to generate at least one image data signal from in response to the image on the pixels of the associated photosensor array, each image data signal comprising at least one image data points;

a first storage area configured to store a first image data signal;

a second storage area configured to store a second image data signal; and

a comparison module configured to measure a similarity of images through the first image data signal and the second image data signal to obtain a displacement value, each image data signal comprising at least one image data points, the comparison module applying a cross-correlation function to a multiple of a shift value on a first randomly patterned image data signal being shifted by a predetermined shift value from a second randomly patterned image data signal.