Apparatus and method for measuring optical characteristics of an object

• US 6,449,041 B1
• Filed: 11/23/1998
• Issued: 09/10/2002
• Est. Priority Date: 07/01/1997
• Status: Expired due to Term

• Current Assignee: RPX Corporation
• Original Assignee: LJ Laboratories L.L.C.
• Inventors: Jung, Wayne D., Jung, Russell W., Loudermilk, Alan R.
• Primary Examiner(s): Font, Frank G.
• Assistant Examiner(s): Nguyen, Tu T.
• Application Number:
  US09/198,591
• Time in Patent Office: 1,387 Days
• Field of Search: 385/13, 356/73, 356/317, 356/318, 356/319, 356/326, 356/328, 356/371, 356/416, 356/417, 356/419, 356/445, 356/446, 433/29, 250/227.11, 250/227.23
• US Class Current: 356/326
• CPC Class Codes: A61B 2560/0233 Optical standards
• CPC Class Codes: A61B 2562/247 Hygienic covers, i.e. for covering the sensor or apparatus during use
• CPC Class Codes: A61B 5/0088 for oral or dental tissue
• CPC Class Codes: A61C 19/10 Supports for artificial teeth for transport or for comparison of the colour
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/0218 using optical fibers
• CPC Class Codes: G01J 3/51 using colour filters
• CPC Class Codes: G01J 3/513 having fixed filter-detector pairs
• CPC Class Codes: G01N 21/474 Details of optical heads therefor, e.g. using optical fibres
• CPC Class Codes: G01N 21/57 Measuring gloss
• CPC Class Codes: G07D 7/1205 Testing spectral properties
• CPC Class Codes: G07D 7/17 Apparatus characterised by positioning means or by means responsive to positioning

Abstract

Optical characteristic measuring systems and methods such as for determining the color or other optical characteristics of teeth are disclosed. Perimeter receiver fiber optics preferably are spaced apart from a source fiber optic and receive light from the surface of the object/tooth being measured. Light from the perimeter fiber optics pass to a variety of filters. The system utilizes the perimeter receiver fiber optics to determine information regarding the height and angle of the probe with respect to the object/tooth being measured. Under processor control, the optical characteristics measurement may be made at a predetermined height and angle. Various color spectral photometer arrangements are disclosed. Translucency, fluorescence, gloss and/or surface texture data also may be obtained. Audio feedback may be provided to guide operator use of the system. The probe may have a removable or shielded tip for contamination prevention. A method of producing dental prostheses based on measured data also is disclosed. Measured data also may be stored and/or organized as part of a patient data base. Such methods and implements may be desirably utilized for purposes of detecting and preventing counterfeiting or the like.

Claims

1. A spectrometer apparatus for determining a characteristic of an object or material comprising:

one or more sensors receiving light from the object or material, wherein the one or more sensors generate at least one signal having a frequency proportional to the light received from the object or material;

a bias light source, wherein the bias light source controllably provides light to one or more of the sensors that is not received from the object or material; and

a processor coupled to receive the at least one signal, wherein the processor determines the characteristic based on the at least one signal.

2. The apparatus of claim 1, wherein the at least one signal comprises a digital signal.

3. The apparatus of claim 2, wherein the digital signal comprises a TTL or CMOS digital signal.

4. The apparatus of claim 1, wherein the light passes through one or more filters prior to being coupled to one or more of the sensors, wherein spectral characteristics are determined based on measuring a period of a plurality of digital signals produced by a plurality of sensors.

5. The apparatus of claim 1, wherein the signal comprises an a synchronous signal of a frequency dependent upon an intensity of the received light.

6. The apparatus of claim 1, wherein the one or more sensors comprise a plurality of light to frequency converter sensing elements.

7. The apparatus of claim 1, wherein the light passes through a filter prior to being coupled to one or more of the sensors, wherein the filter comprises a plurality of filter portions having a wavelength dependent optical transmission property.

8. The apparatus of claim 1, wherein the characteristic comprises a spectral analysis based on light received from the object or material.

9. The apparatus of claim 1, wherein the light passes through a filter prior to being coupled to one or more of the sensors, wherein the filter comprises a plurality of cut-off filter elements.

10. The apparatus of claim 1, wherein the light passes through a filter prior to being coupled to one or more of the sensors, wherein the filter comprises a color gradient filter.

11. The apparatus of claim 1, wherein the light passes through a filter prior to being coupled to one or more of the sensors, wherein the filter comprises a filter grid.

12. The apparatus of claim 1, wherein the light passes through one or more filters prior to being coupled to one or more of the sensors, wherein the received light is spectrally analyzed without using a diffraction grating.

13. The apparatus of claim 1, wherein the light is received by a probe, wherein a plurality of measurements are taken at a plurality of distances of the probe with respect to the object or material.

14. The apparatus of claim 1, wherein a probe having one or more light sources provides light to the object or material, wherein light from the one or more light sources is received by one or more light receivers from the object or material.

15. The apparatus of claim 14, wherein one or more sensors determine a distance of the probe with respect to the object or material.

16. The apparatus of claim 14, wherein one or more sensors determine an angle of the probe with respect to the object or material.

17. The apparatus of claim 14, wherein one or more sensors determine a distance and an angle of the probe with respect to the object or material.

18. The apparatus of claim 1, wherein the at least one signal having a frequency proportional to the light received by the one or more sensors is generated by an integrator coupled to the one or more sensors.

19. The apparatus of claim 1, wherein the sensors comprise a photo detector.

20. The apparatus of claim 19, wherein the photo detector comprises a photo diode.

21. The apparatus of claim 19, wherein the photo detector comprises a photo diode array.

22. The apparatus of claim 1, wherein the light passes through one or more filters prior to being coupled to one or more of the sensors.

23. The apparatus of claim 1, wherein the processor comprises a microprocessor.

24. The apparatus of claim 1, wherein the processor comprises logic.

25. The apparatus of claim 24, wherein the logic comprises a logic array.

26. The apparatus of claim 24, wherein the processor comprises a programmable logic array.

27. The apparatus of claim 1, further comprising one or more light receivers for receiving light from the object or material, wherein the one or more sensors receive light from the one or more receivers.

28. The apparatus of claim 1, wherein the object or material comprises a non-gaseous material, skin, non-skin body tissue, paint, fabric, a photograph, a dental object, a printed object, hair, or makeup.

29. The apparatus of claim 1, wherein the one or more sensors are controlled to sample received light at a minimum sampling period.

30. The apparatus of claim 29, wherein the bias light source provides light to one or more of the sensors that is not received from the object or material at a level to ensure that the one or more of the sensors generate a signal in the minimum sampling period.

31. The apparatus of claim 30, wherein the signal in the minimum sampling period comprises a signal having a predetermined minimum number of transitions.

32. The apparatus of claim 31, wherein the predetermined minimum number of transitions comprises at least two transitions.

33. The apparatus of claim 29, wherein the bias light source is controlled so that the at least one signal has a frequency so that a measurement is taken by the one or more sensors in the minimum sampling period.

34. The apparatus of claim 33, wherein the measurement comprises measuring at least the frequency and period of the at least one signal.

35. The apparatus of claim 1, wherein the bias light source comprises a light source that also provides light to the object or material.

36. The apparatus of claim 1, wherein the bias light source comprises a light source different from a light source that provides light to the object or material.

37. The apparatus of claim 1, wherein the bias light source comprises a broadband light source.

38. The apparatus of claim 1, wherein the bias light source comprises a monochromatic light source.

39. The apparatus of claim 38, wherein the bias light source comprises an LED.

40. The apparatus of claim 1, wherein a bias tracking sensor is provided that receives light from the bias light source but not light received from the object or material.

41. The apparatus of claim 40, wherein the bias tracking sensor provides an output that is used to correct for fluctuations in the light output from the bias light source.

42. A spectrometer apparatus for determining a characteristic of an object or material comprising:

one or more sensors receiving light from the object or material, wherein the one or more sensors generate at least one output signal based on the light received from the object or material;

a bias light source, wherein the bias light source controllably provides light to one or more of the sensors that is not received from the object or material; and

a processor coupled to receive the at least one signal, wherein the processor determines the characteristic based on the at least one signal.

43. The apparatus of claim 42, wherein the at least one signal comprises a digital signal.

44. The apparatus of claim 43, wherein the digital signal comprises a TTL or CMOS digital signal.

45. The apparatus of claim 42, wherein the light passes through one or more filters prior to being coupled to one or more of the sensors, wherein spectral characteristics are determined based on measuring a period of a plurality of digital signals produced by a plurality of sensors.

46. The apparatus of claim 42, wherein the signal comprises an a synchronous signal of a frequency dependent upon an intensity of the received light.

47. The apparatus of claim 42, wherein the one or more sensors comprise a plurality of light to frequency converter sensing elements.

48. The apparatus of claim 42, wherein the light passes through a filter prior to being coupled to one or more of the sensors, wherein the filter comprises a plurality of filter portions having a wavelength dependent optical transmission property.

49. The apparatus of claim 42, wherein the characteristic comprises a spectral analysis based on light received from the object or material.

50. The apparatus of claim 42, wherein the light passes through a filter prior to being coupled to one or more of the sensors, wherein the filter comprises a plurality of cut-off filter elements.

51. The apparatus of claim 42, wherein the light passes through a filter prior to being coupled to one or more of the sensors, wherein the filter comprises a color gradient filter.

52. The apparatus of claim 42, wherein the light passes through a filter prior to being coupled to one or more of the sensors, wherein the filter comprises a filter grid.

53. The apparatus of claim 42, wherein the light passes through one or more filters prior to being coupled to one or more of the sensors, wherein the received light is spectrally analyzed without using a diffraction grating.

54. The apparatus of claim 42, wherein the light is received by a probe, wherein a plurality of measurements are taken at a plurality of distances of the probe with respect to the object or material.

55. The apparatus of claim 42, wherein a probe having one or more light sources provides light to the object or material, wherein light from the one or more light sources is received by one or more light receivers from the object or material.

56. The apparatus of claim 55, wherein one or more sensors determine a distance of the probe with respect to the object or material.

57. The apparatus of claim 55, wherein one or more sensors determine an angle of the probe with respect to the object or material.

58. The apparatus of claim 55, wherein one or more sensors determine a distance and an angle of the probe with respect to the object or material.

59. The apparatus of claim 42, wherein the at least one signal having a frequency proportional to the light received by the one or more sensors is generated by an integrator coupled to the one or more sensors.

60. The apparatus of claim 42, wherein the sensors comprise a photo detector.

61. The apparatus of claim 60, wherein the photo detector comprises a photo diode.

63. The apparatus of claim 42, wherein the light passes through one or more filters prior to being coupled to one or more of the sensors.

64. The apparatus of claim 42, wherein the processor comprises a microprocessor.

65. The apparatus of claim 42, wherein the processor comprises logic.

66. The apparatus of claim 65, wherein the logic comprises a logic array.

67. The apparatus of claim 65, wherein the processor comprises a programmable logic array.

68. The apparatus of claim 42, further comprising one or more light receivers for receiving light from the object or material, wherein the one or more sensors receive light from the one or more receivers.

69. The apparatus of claim 42, wherein the object or material comprises a non-gaseous material, skin, non-skin body tissue, paint, fabric, a photograph, a dental object, a printed object, hair, or makeup.

70. The apparatus of claim 42, wherein the one or more sensors are controlled to sample received light at a minimum sampling period.

71. The apparatus of claim 70, wherein the bias light source provides light to one or more of the sensors that is not received from the object or material at a level to ensure that the one or more of the sensors generate a signal in the minimum sampling period.

72. The apparatus of claim 71, wherein the signal in the minimum sampling period comprises a signal having a predetermined minimum number of transitions.

73. The apparatus of claim 72, wherein the predetermined minimum number of transitions comprises at least two transitions.

74. The apparatus of claim 70, wherein the bias light source is controlled so that the at least one signal has a frequency so that a measurement is taken by the one or more sensors in the minimum sampling period.

75. The apparatus of claim 74, wherein the measurement comprises measuring at least the frequency and period of the at least one signal.

76. The apparatus of claim 42, wherein the bias light source comprises a light source that also provides light to the object or material.

77. The apparatus of claim 42, wherein the bias light source comprises a light source different from a light source that provides light to the object or material.

78. The apparatus of claim 42, wherein the bias light source comprises a broadband light source.

79. The apparatus of claim 42, wherein the bias light source comprises a monochromatic light source.

80. The apparatus of claim 79, wherein the bias light source comprises an LED.

81. The apparatus of claim 42, wherein a bias tracking sensor is provided that receives light from the bias light source but not light received from the object or material.

82. The apparatus of claim 81, wherein the bias tracking sensor provides an output that is used to correct for fluctuations in the light output from the bias light source.

62. The apparatus of claim 0, wherein the photo detector comprises a photo diode array.