Apparatus for measuring optical characteristics of a substrate and pigments applied thereto

• US 6,373,573 B1
• Filed: 03/13/2000
• Issued: 04/16/2002
• Est. Priority Date: 03/13/2000
• Status: Expired due to Term

• Current Assignee: JJL Technologies, L.L.C., RPX Corporation
• Original Assignee: LJ Laboratories L.L.C.
• Inventors: Jung, Wayne D., Jung, Russell W., Loudermilk, Alan R.
• Primary Examiner(s): EVANS, FANNIE L
• Application Number:
  US09/524,121
• Time in Patent Office: 764 Days
• Field of Search: 356/319, 356/326, 356/328, 356/416, 356/419, 250/226, 347/19
• US Class Current: 356/419
• CPC Class Codes: A61B 2560/0233 Optical standards
• CPC Class Codes: A61B 5/0075 by spectroscopy, i.e. measuring spectra, e.g. Raman spectroscopy, infrared absorption spectroscopy A61B5/0071 takes precedence
• CPC Class Codes: A61B 5/0084 for introduction into the body, e.g. by catheters A61B5/1459 takes precedence
• CPC Class Codes: A61B 5/0088 for oral or dental tissue
• CPC Class Codes: A61B 5/1034 by means of colour cards
• CPC Class Codes: A61B 5/4547 Evaluating teeth
• CPC Class Codes: A61C 19/10 Supports for artificial teeth for transport or for comparison of the colour
• CPC Class Codes: G01J 2003/1213 Filters in general, e.g. dichroic, band
• CPC Class Codes: G01J 2003/2869 Background correcting
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/0205 Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows
• CPC Class Codes: G01J 3/0218 using optical fibers
• CPC Class Codes: G01J 3/0229 using masks, aperture plates, spatial light modulators or spatial filters, e.g. reflective filters
• CPC Class Codes: G01J 3/0251 Colorimeters making use of an integrating sphere
• CPC Class Codes: G01J 3/0262 Constructional arrangements for removing stray light
• CPC Class Codes: G01J 3/0264 Electrical interface; User interface
• CPC Class Codes: G01J 3/04 Slit arrangements slit adjustment
• CPC Class Codes: G01J 3/10 Arrangements of light sources specially adapted for spectrometry or colorimetry
• CPC Class Codes: G01J 3/2803 using photoelectric array detector
• CPC Class Codes: G01J 3/46 Measurement of colour; Colour measuring devices, e.g. colorimeters measuring colour temperature G01J5/60
• CPC Class Codes: G01J 3/50 : using electric radiation detectors
• CPC Class Codes: G01J 3/508 : measuring the colour of teeth
• CPC Class Codes: G01J 3/51 : using colour filters
• CPC Class Codes: G01J 3/513 : having fixed filter-detector pairs
• CPC Class Codes: G01J 3/524 : Calibration of colorimeters
• CPC Class Codes: G01N 2021/6484 : Optical fibres
• CPC Class Codes: G01N 21/255 : Details, e.g. use of specially adapted sources, lighting or optical systems
• 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: G01N 21/6486 : Measuring fluorescence of biological material, e.g. DNA, RNA, cells G01N21/6428 takes precedence

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. Low cost and small form factor spectrometers, and methods for manufacturing the same, also are disclosed. Spectrometers and spectrophotometers embedded in printing and scanning and other type devices, as well as computer companion devices, scope-type devices and the like, also are disclosed. Data encoding based on such devices also may be implemented.

Claims

1. A system for applying pigment to a substrate, comprising:

a spectophotometer integral to the system supplying light to the substrate and receiving light from the substrate, wherein the light received from the substrate is spectrally analyzed by a spectrometer,

one or more pigment dischargers integral to the system, wherein the one or more pigment dischargers apply one or more pigments to the substrate;

wherein, the spectrometer spectrally analyzes the one or more pigments applied to the substrate or spectrally analyzes the substrate at one or more points on the substrate, wherein the one or more points on the substrate do not have the one or more pigments applied thereto;

wherein the spectrometer comprises;

an optical sensing circuit having thereon a plurality of optical sensors and one or more processing elements;

a plurality of filter elements fixedly positioned over at least a first group of the optical sensors, wherein each of the plurality of filter elements have spectral transmission characteristics over predetermined wavelengths;

an optical manifold fixedly positioned over at least certain of the plurality of filter elements, wherein the optical manifold has a plurality of exit windows and at least one entrance port, wherein light entering the entrance port is transmitted to an intenor portion of the optical manifold, wherein at least a portion of the light is transmitted from the exit ports through at least certain of the filter elements for sensing by at least certain of the optical sensors;

wherein light may be coupled from the substrate to the entrance port, wherein spectral data corresponding to the light is generated by the one or more processing elements, wherein the spectrometer is fabricated in a unitary manner.

2. The system of claim 1, wherein, in response to the spectral analysis of the one or more pigments applied to the substrate, data is fed back to the one or more pigment dischagers, wherein the one or more pigment dischargers operate responsive to the data that is fed back.

3. The system of claim 2, wherein, in response to the data that is fed back, an alarm is selectively activated.

4. The system of claim 2, wherein, in response to the data that is fed back, the one or more pigment dischargers are controlled to apply the one or more pigments to the substrate in order to produce desired spectral characteristics.

5. The system of claim 1, wherein the spectrometer spectrally analyzes one or more regions of the substrate prior to the applying of the one or more pigments to the substrate, wherein, in response to the spectral analysis of the substrate, data is fed back to the one or more pigment dischargers, wherein the one or more pigment dischargers operate responsive to the data that is fed back.

6. The system of claim 5, wherein the one or more pigment dischargers are controlled at least in part based on optical characteristics of the substrate.

7. The system of claim 5, wherein, in response to spectral characteristics of the substrate, the one or more pigment dischargers are controlled to apply the one or more pigments to the substrate in order to produce desired spectral characteristics.

8. The system of claim 7, wherein the one or more pigments are applied to the substrate in the form of patterns of dots in a unit cell, wherein, in response to spectral characteristics of the substrate, the one or more pigment dischargers are controlled to apply the one or more pigments to the substrate so that a dot pattern, a number of dots in the unit cell, and/or a size of the dots are varied to produce desired spectral characteristics.

9. The system of claim 7, wherein a quantity of the one or more pigments applied to a unit area of the substrate are controlled to produce desired speceral characteristics.

10. The system of claim 5, wherein the substrate is scanned by the spectrometer prior to the applying of the one or more pigments to the substrate.

11. The system of claim 10, wherein the one or more pigment dischargers are controlled at least in part based on optical characteristics of the substrate.

12. The system of claim 10, wherein, in response to the scanning of the substrate, one or more regions of the substrate are determined, wherein the one or more pigments are applied to the one or more regions.

13. The system of claim 10, wherein the entire substrate is scanned or predetermined portions of the substrate are scanned prior to the applying of the one or more pigments to the substrate.

14. The system of claim 10, wherein the substrate is selectively accepted or rejected based on the scanning of the substrate.

15. The system of claim 10, wherein a spectral map of the substrate is generated, wherein the one or more pigment dischargers operate responsive to the spectral map of the substrate.

16. The system of claim 10, wherein one or more regions of a first substrate are scanned by the spectrometer, wherein, in response to the scanning of the one or more regions of the first substrate, the one or more pigments are applied to one or more regions of a second substrate.

17. The system of claim 16, wherein in response to optical characteristics of the first substrate, the one or more pigments are applied to the second substrate to produce desired spectral characteristics on the second substrate.

18. The system of claim 2, wherein the substrate includes at least a first region and a second region, wherein the spectrometer spectrally analyzes the first region of the substrate on which the one or more pigments are applied, wherein, in response to the spectral analysis of the first region of the substrate, the one or more pigments are applied to the second region of the substrate.

19. The system of claim 18, wherein the one or more pigments are applied to the second region of the substrate in order to produce desired spectral characteristics in the second region.

20. The system of claim 18, wherein the first region of the substrate comprises a test region.

21. The system of claim 18, wherein the first region of the substrate comprises a region in a peripheral area of the substrate.

22. The system of claim 2, wherein the one or more pigment dischargers move with respect to the substrate, wherein the spectrometer is in a substantially fixed position with respect to the one or more pigment dischargers.

23. The system of claim 22, wherein, the one or more pigment dischargers apply the one or more pigments on a first region of the substrate at a first point in time, wherein the one or more pigment dischargers move with respect to the substrate and the one or more pigment dischargers apply the one or more pigments on a second region of the substrate at a second point in time, wherein, at least during a portion of the time that the one or more pigment dischargers apply the one or more pigments on the second region of the substrate, the spectrometer is spectrally analyzing the first region of the substrate.

24. The system of claim 23, wherein, in response to the spectral analysis of the first region of the substrate, data is fed back to the one or more pigment dischargers, wherein the one or more pigment dischargers operate responsive to the data that is fed back.

25. The system of claim 1, wherein, in response to the spectral analysis of the one or more pigments applied to the substrate, an alarm is selectively activated, an error message is selectively displayed, and/or operation of the one or more pigment dischargers is selectively interrupted.

26. The system of claim 25, wherein an indication that maintenance is needed for the system is selectively provided.

27. The system of claim 26, wherein an indication that the one or more pigment dischargers need to be serviced is selectively provided.

28. The system of claim 27, wherein an indication that one or more pigment discharging heads need to be replaced is selectively provided.

29. The system of claim 1, wherein, in response to the spectral analysis of the one or more pigments applied to the substrate, a processor estimates an estimated remaining service/life of the one or more pigment dischargers.

30. The system of claim 29, wherein the processor outputs the estimated remaining life in terms of an estimated number of substrates that may be processed by the system or an estimated time for replacement or servicing of the one or more pigment discharges.

31. The system of claim 29, wherein the processor selectively disables the one or more pigment dischargers in order to prevent undesired spectral characteristics from being produced on the substrate.

32. The system of claim 1, wherein, in response to the spectral analysis of the one or more pigments applied to the substrate, a processor selectively initiates a procedure for cleaning the one or more pigment dischargers.

34. The system of claim 1, wherein the system receives a print data file from a computing device, wherein the spectrometer selectively operates in response to data in the print data file.

35. The system of claim 34, wherein the spectrometer selectively shuts off if data in the print data file indicates that a monochromatic print operation is to be performed.

36. The system of claim 1, wherein a light source integral to the system provides light to the substrate, wherein the spectrometer spectrally analyzes light from the light souse that is returned from the substrate.

37. The system of claim 36, wherein a processor monitors an output of the light source.

38. The system of claim 37, wherein the spectrometer spectrally analyzes the substrate based on data generated based on the monitoring of the output of the light source.

39. The system of claim 36, wherein a calibration standard is integral to the system, wherein the spectrometer periodically spectrally analyzes the calibration standard.

40. The system of claim 1, wherein the substrate on which the one or more pigments are applied comprises, in whole or part, an image, an article for advertising, a passport, currency, a stock or bond certificate, a ticket for a sporting or other event, a coupon, or postage.

41. The system of claim 1, wherein an article is produced having one or more regions of known spectral characteristics, wherein the system couples data indicative of the known spectral characteristics to a remote computer over a network.

42. The system of claim 41, wherein at a subsequent point in time a spectral analysis of the article is performed to determine if the article is genuine.

43. The system of claim 42, wherein the spectral analysis of the article is performed at a location remote from a location where the article was produced.

44. The system of claim 43, wherein the article comprises an article on which postage is applied, currency, a stock, bond or other certificate, a passport or other government document, a ticket or a coupon.

45. The system of claim 1, wherein the one or more pigments comprise paint or ink.

46. The system of claim 1, wherein the substrate comprises paper, fabric, plastic or metal.

47. The system of claim 1, wherein the optical sensors comprise a plurality of light to frequency converter sensing elements.

48. The system of claim 1, wherein the filter elements each comprise a filter having a wavelength dependent optical transmission property.

49. The system of claim 1, wherein the filter elements each comprise a cut-off filter element.

50. The system of claim 1, wherein the plurality of filter elements comprise a color gradient filter or a filter grid.

51. The system of claim 1, wherein the light received from the substrate is spectrally analyzed without using a diffraction grating.

33. The system of clam 1, wherein a multi-pass pigment discharging operation is performed, wherein in a first pass the one or more pigments are applied to the substrate, wherein, in response to the spectral analysis of the one or more pigments applied to the substrate in the first pass, the one or more pigments are selectively applied or not applied to the substrate in the second pass.

52. A system for applying pigment to a substrate, comprising:

a spectrophotometer integral to the system supplying light to the substrate and receiving light from the substrate, wherein the light received from the substrate is spectrally analyzed by a spectrometer;

one or more pigment dischargers integral to the system, wherein the one or more pigment dischargers apply one or more pigments to the substrate;

wherein, the spectrometer spectrally analyzes the one or more pigments applied to the substrate or spectrally analyzes the substrate at one or more points on the substrate, wherein the one or more points on the substrate do not have the one or more pigments applied thereto;

wherein the spectrometer comprises;

an optical sensing circuit having thereon a plurality of optical sensors and one or more processing elements;

a plurality of filters fixedly positioned over at least a first group of the optical sensors, wherein each of the plurality of filters have spectral transmission characteristics over predetermined wavelengths;

an optical manifold comprising at least a fiber optic bundle having at least one input and a plurality of outputs fixedly positioned over at least certain of the plurality of filters, wherein light entering the input is transmitted to an interior portion of the optical manifold, wherein at least a portion of the light is transmitted from the outputs through at least certain of the filters for sensing by at least certain of the optical sensors;

wherein light may be coupled from the substrate to the input, wherein spectral data corresponding to the light is generated by the one or more processing elements, wherein the spectrometer is fabricated in a unitary manner.

53. The system of claim 52, wherein, in response to the spectral analysis of the one or more pigments applied to the substrate, data is fed back to the one or more pigment dischargers, wherein the one or more pigment dischargers operate responsive to the data that is fed back.

54. The system of claim 53, wherein, in response to the data that is fed back, an alarm is selectively activated.

55. The system of claim 53, wherein, in response to the data that is fed back, the one or more pigment dischargers are controlled to apply the one or more pigments to the substrate in order to produce desired spectral characteristics.

56. The system of claim 52, wherein the spectrometer spectrally analyzes one or more regions of the substrate prior to the applying of the one or more pigments to the substrate, wherein, in response to the spectral analysis of the substrate, data is fed back to the one or more pigment dischargers, wherein the one or more pigment dischargers operate responsive to the data that is fed back.

57. The system of claim 56, wherein the one or more pigment dischargers are controlled at least in part based on optical characteristics of the substrate.

58. The system of claim 56, wherein, in response to spectral characteristics of the substrate, the one or more pigment dischargers are controlled to apply the one or more pigments to the substrate in order to produce desired spectral characteristics.

59. The system of claim 58, wherein the one or more pigments are applied to the substrate in the form of patterns of dots in a unit cell, wherein, in response to spectral characteristics of the substrate, the one or more pigment dischargers are controlled to apply the one or more pigments to the substrate so that a dot pattern, a number of dots in the unit cell, and/or a size of the dots are varied to produce desired spectral characteristics.

60. The system of claim 58, wherein a quantity of the one or more pigments applied to a unit area of the substrate are controlled to produce desired spectral characteristics.

61. The system of claim 56, wherein the substrate is scanned by the spectrometer prior to the applying of the one or more pigments to the substrate.

62. The system of claim 61, wherein the one or more pigment dischargers are controlled at least in part based on optical characteristics of the substrate.

63. The system of claim 61, wherein, in response to the scanning of the substrate, one or more regions of the substrate are determined wherein the one or more pigments are applied to the one or more regions.

64. The system of claim 61, wherein the entire substrate is scanned or predetermined portions of the substrate are scanned prior to the applying of the one or more pigments to the substrate.

65. The system of claim 61, wherein the substrate is selectively accepted or rejected based on the scan of the substrate.

66. The system of claim 61, wherein a spectral map of the substrate is generated, wherein the one or more pigment dischargers operate responsive to the spectral map of the substrate.

67. The system of claim 61, wherein one or more regions of a first substrate are scanned by the spectrometer, wherein, in response to the scanning of the one or more regions of the first substrate, the one or more pigments are applied to one or more regions of a second substrate.

68. The system of claim 67, wherein in response to optical characteristics of the first substrate, the one or more pigments are applied to the second substrate to produce desired spectral characteristics on the second substrate.

69. The system of claim 53, wherein the substrate includes at least a first region and a second region, wherein the spectrometer spectrally analyzes the first region of the substrate on which the one or more pigments are applied, wherein, in response to the spectral analysis of the first region of the substrate, the one or more pigments are applied to the second region of the substrate.

70. The system of claim 69, wherein the one or more pigments are applied to the second region of the substrate in order to produce desired spectral characteristics in the second region.

71. The system of claim 69, wherein the first region of the substrate comprises a test region.

72. The system of claim 69, wherein the first region of the substrate comprises a region in a peripheral area of the substrate.

73. The system of claim 53, wherein the one or more pigment dischargers move with respect to the substrate, wherein the spectrometer is in a substantially fixed position with respect to the one or more pigment dischargers.

74. The system of claim 73, wherein, the one or more pigment dischargers apply the one or more pigments on a first region of the substrate at a first point in time, wherein the one or more pigment dischargers move with respect to the substrate and the one or more pigment dischargers apply the one or more pigments on a second region of the substrate at a second point in time, wherein, at least during a portion of the time that the one or more pigment dischargers apply the one or more pigments on the second region of the substrate, the spectrometer is spectrally analyzing the first region of the substrate.

75. The system of claim 74, wherein, in response to the spectral analysis of the first region of the substrate, data is fed back to the one or more pigment dischargers, wherein the one or more pigment dischagers operate responsive to the data that is fed back.

76. The system of claim 52, wherein, in response to the spectral analysis of the one or more pigments applied to the substrate, an alarm is selectively activated, an error message is selectively displayed, and/or operation of the one or more pigment dischargers is selectively interrupted.

80. The system of claim 52, wherein, in response to the spectral analysis of the one or more pigments applied to the substrate, a processor estimates an estimated remaining service/life of the one or more pigment dischargers.

81. The system of claim 80, wherein the processor outputs the estimated remaining life in terms of an estimated number of substrates that may be processed by the system or an estimated time for replacement or servicing of the one or more pigment dischargers.

82. The system of claim 80, wherein the processor selectively disables the one or more pigment dischargers in order to prevent undesired spectral characteristics from being produced on the substrate.

83. The system of claim 52, wherein, in response to the spectral analysis of the one or more pigments applied to the substrate, a processor selectively initiates a procedure for cleaning the one or more pigment dischargers.

84. The system of claim 52, wherein a multi-pass pigment discharging operation is performed, wherein in a first pass the one or more pigments are applied to the substrate, wherein, in response to the spectral analysis of the one or more pigments applied to the substrate in the first pass, the one or more pigments are selectively applied or not applied to the substrate in the second pass.

85. The system of claim 52, wherein the system receives a print data file from a computing device, wherein the spectrometer selectively operates in response to data in the print data file.

86. The system of claim 85, wherein the spectrometer selectively shuts off if data in the print data file indicates that a monochromatic print operation is to be performed.

87. The system of claim 52, wherein a light source integral to the system provides light to the substrate, wherein the spectrometer spectrally analyzes light from the light source that is returned from the substrate.

88. The system of claim 87, wherein a processor monitors an output of the light source.

89. The system of claim 88, wherein the spectrometer spectrally analyzes the substrate based on data generated based on the monitoring of the output of the light source.

90. The system of claim 87, wherein a calibration standard is integral to the system, wherein the spectrometer periodically spectrally analyzes the calibration standard.

91. The system of claim 52, wherein the substrate on which the one or more pigments are applied comprises, in whole or part, an image, an article for advertising, a passport, currency, a stock or bond certificate, a ticket for a sporting or other event, a coupon, or postage.

92. The system of claim 52, wherein an article is produced having one or more regions of known spectral characteristics, wherein the system couples data indicative of the known spectral characteristics to a remote computer over a network.

93. The system of claim 92, wherein at a subsequent point in time a spectral analysis of the article is performed to determine if the article is genuine.

94. The system of claim 93, wherein the spectral analysis of the article is performed at a location remote from a location where the article was produced.

95. The system of claim 94, wherein the article comprises an article on which postage is applied, currency, a stock, bond or other certificate, a passport or other government document, a ticket or a coupon.

96. The system of claim 52, wherein the one or more pigments comprise paint or ink.

97. The system of claim 52, wherein the substrate comprises paper, fabric, plastic or metal.

98. The system of claim 52, wherein the optical sensors comprise a plurality of light to frequency converter sensing elements.

99. The system of claim 52, wherein the filter elements each comprise a filter having a wavelength dependent optical transmission property.

100. The system of claim 52, wherein the filter elements each comprise a cut-off filter element.

101. The system of claim 52, wherein the plurality of filter elements comprise a color gradient filter or a filter grid.

102. The system of claim 52, wherein the light received from the substrate is spectrally analyzed without using a diffraction grating.

77. The system of clan 76, wherein an indication that maintenance is needed for the system is selectively provided.

78. The system of claim 77, wherein an indication that the one or more pigment dischargers need to be serviced is selectively provided.

79. The system of claim 78, wherein an indication that one or more pigment discharging heads need to be replaced is selectively provided.

103. A system for applying pigment to a substrate, comprising:

a spectrophotometer integral to the system supplying light to the substrate and receiving light from the substrate, wherein the light received from the substrate is spectrally analyzed by a spectrometer;

one or more pigment dischargers integral to the system, wherein the one or more pigment dischargers apply one or more pigments to the substrate;

wherein, the spectrometer spectrally analyzes the one or more pigments applied to the substrate or spectrally analyzes the substrate at one or more points on the substrate, wherein the one or more points on the substrate do not have the one or more pigments applied thereto;

wherein the spectrometer comprises;

an optical sensing circuit having thereon a plurality of optical sensors and one or more processing elements, wherein the plurality of optical sensors include an array of sensors each of which generates a signal having a frequency proportional to the light intensity received by the particular sensor;

a plurality of filters fixedly positioned over at least a first group of the optical sensors including at least a portion of the array of sensors, wherein each of the plurality of filters have spectral transmission characteristics over predetermined wavelengths;

a processing circuit, wherein the processing circuit receives from a plurality of the optical sensors at least a plurality of signals having a frequency proportional to the light intensity received by the particular sensors, wherein spectral data is generated by the processing circuit based at least in part on the plurality of signals.

104. The system of claim 103, wherein, in response to the spectral analysis of the one or more pigments applied to the substrate, data is fed back to the one or more pigment dischargers, wherein the one or more pigment dischargers operate responsive to the data that is fed back.

105. The system of claim 104, wherein, in response to the data that is fed back, an alarm is selectively activated.

106. The system of claim 104, wherein, in response to the data that is fed back, the one or more pigment dischargers are controlled to apply the one or more pigments to the substrate in order to produce desired spectral characteristics.

107. The system of claim 103, wherein the spectrometer spectrally analyzes one or more regions of the substrate prior to the applying of the one or more pigments to the substrate, wherein, in response to the spectral analysis of the substrate, data is fed back to the one or more pigment dischargers, wherein the one or more pigment dischargers operate responsive to the data that is fed back.

108. The system of claim 107, wherein the one or more pigment dischargers are controlled at least in part based on optical characteristics of the substrate.

109. The system of claim 107, wherein, in response to spectral characteristics of the substrate, the one or more pigment dischargers are controlled to apply the one or more pigments to the substrate in order to produce desired spectral characteristics.

110. The system of claim 109, wherein the one or more pigments are applied to the substrate in the form of patterns of dots in a unit cell, wherein, in response to spectral characteristics of the substrate, the one or more pigment dischargers are controlled to apply the one or more pigments to the substrate so that a dot pattern, a number of dots in the unit cell, and/or a size of the dots are varied to produce desired spectral characteristics.

111. The system of claim 109, wherein a quantity of the one or more pigments applied to a unit area of the substrate are controlled to produce desired spectral characteristics.

112. The system of claim 107, wherein the substrate is scanned by the spectrometer prior to the applying of the one or more pigments to the substrate.

113. The system of claim 112, wherein the one or more pigment dischargers are controlled at least in part based on optical characteristics of the substrate.

114. The system of claim 112, wherein, in response to the scanning of the substrate, one or more regions of the substrate are determined, wherein the one or more pigments are applied to the one or more regions.

115. The system of claim 112, wherein the entire substrate is scanned or predetermined portions of the substrate are scanned prior to the applying of the one or more pigments to the substrate.

116. The system of claim 112, wherein the substrate is selectively accepted or rejected based on the scanning of the substrate.

117. The system of claim 112, wherein a spectral map of the substrate is generated, wherein the one or more pigment dischargers operate responsive to the spectral map of the substrate.

118. The system of claim 112, wherein one or more regions of a first substrate are scanned by the spectrometer, wherein, in response to the scanning of the one or more regions of the first substrate, the one or more pigments are applied to one or more regions of a second substrate.

119. The system of claim 118, wherein in response to optical characteristics of the first substrate, the one or more pigments are applied to the second substrate to produce desired spectral characteristics on the second substrate.

120. The system of claim 114, wherein the substrate includes at least a first region and a second region, wherein the spectrometer spectrally analyzes the first region of the substrate on which the one or more pigments are applied, wherein, in response to the spectral analysis of the first region of the substrate, the one or more pigments are applied to the second region of the substrate.

121. The system of claim 120, wherein the one or more pigments are applied to the second region of the substrate in order to produce desired spectral characteristics in the second region.

122. The system of claim 120, wherein the first region of the substrate comprises a test region.

123. The system of claim 120, wherein the first region of the substrate comprises a region in a peripheral area of the substrate.

124. The system of claim 104, wherein the one or more pigment dischargers move with respect to the substrate, wherein the spectrometer is in a substantially fixed position with respect to the one or more pigment dischargers.

125. The system of claim 124, wherein the one or more pigment dischargers apply the one or more pigments on a first region of the substrate at a first point in time, wherein the one or more pigment dischargers move with respect to the substrate and the one or more pigment dischargers apply the one or more pigments on a second region of the substrate at a second point in time, wherein, at least during a portion of the time that the one or more pigment dischargers apply the one or more pigments on the second region of the substrate, the spectrometer is spectrally analyzing the first region of the substrate.

126. The system of claim 125, wherein, in response to the spectral analysis of the first region of the substrate, data is fed back to the one or more pigment dischargers, wherein the one or more pigment dischargers operate responsive to the data that is fed back.

127. The system of claim 103, wherein, in response to the spectral analysis of the one or more pigments applied to the substrate, an alarm is selectively activated, an error message is selectively displayed, and/or operation of the one or more pigment dischargers is selectively interrupted.

128. The system of claim 127, wherein an indication that maintenance is needed for the system is selectively provided.

129. The system of claim 128, wherein an indication that the one or more pigment dischargers need to be serviced is selectively provided.

130. The system of claim 129, wherein an indication that one or more pigment discharging heads need to be replaced is selectively provided.

131. The system of claim 103, wherein, in response to the spectral analysis of the one or more pigments applied to the substrate, a processor estimates an estimated remaining service/life of the one or more pigment dischargers.

132. The system of claim 131, wherein the processor outputs the estimated remaining life in terms of an estimated number of substrates that may be processed by the system or an estimated time for replacement or servicing of the one or more pigment dischargers.

133. The system of claim 131, wherein the processor selectively disables the one or more pigment dischargers in order to prevent undesired spectral characteristics from being produced on the substrate.

134. The system of claim 103, wherein, in response to the spectral analysis of the one or more pigments applied to the substrate, a processor selectively initiates a procedure for cleaning the one or more pigment dischargers.

135. The system of claim 103, wherein a multi-pass pigment discharging operation is performed, wherein in a first pass the one or more pigments are applied to the substrate, wherein, in response to the spectral analysis of the one or more pigments applied to the substrate in the first pass, the one or more pigments are selectively applied or not applied to the substrate in the second pass.

136. The system of claim 103, wherein the system receives a print data file from a computing device, wherein the spectrometer selectively operates in response to data in the print data file.

137. The system of claim 136, wherein the spectrometer selectively shuts off if data in the print data file indicates that a monochromatic print operation is to be performed.

138. The system of claim 103, wherein a light source integral to the system provides light to the substrate, wherein the spectrometer spectrally analyzes light from the light source that is returned from the substrate.

139. The system of claim 138, wherein a processor monitors an output of the light source.

140. The system of claim 139, wherein the spectroneter spectrally analyzes the substrate based on data generated based on the monitoring of the output of the light source.

141. The system of claim 138, wherein a calibration standard is integral to the system, wherein the spectrometer periodically spectrally analyzes the calibration standard.

142. The system of claim 103, wherein the substrate on which the one or more pigments are applied comprises, in whole or part, an image, an article for advertising, a passport, currency, a stock or bond certificate, a ticket for a sporting or other event, a coupon, or postage.

143. The system of claim 103, wherein an article is produced having one or more regions of known spectral characteristics, wherein the system couples data indicative of the known spectral characteristics to a remote computer over a network.

144. The system of claim 143, wherein at a subsequent point in time a spectral analysis of the article is performed to determine if the article is genuine.

145. The system of claim 144, wherein the spectral analysis of the article is performed at a location remote from a location where the article was produced.

146. The system of claim 145, wherein the article comprises an article on which postage is applied, currency, a stock, bond or other certificate, a passport or other government document, a ticket or a coupon.

147. The system of claim 103, wherein the one or more pigments comprise paint or ink.

148. The system of claim 103, wherein the substrate comprises paper, fabric, plastic or metal.

149. The system of claim 103, wherein each of the signals having a frequency proportional to the light intensity received by the particular sensor comprises a digital signal.

150. The system of claim 149, wherein the digital signals comprise a TTL or CMOS digital signal.

151. The system of claim 149, wherein the spectral data is generated based on measuring a period of a plurality of digital signals produced by a plurality of sensors.

152. The system of claim 149, wherein each of the signals having a frequency proportional to the light intensity received by the particular sensor comprises an asynchronous signal of a frequency dependent upon the intensity of light received by the particular sensor.

153. The system of claim 149, wherein the array of sensors comprise a plurality of light to frequency converter sensing elements.

154. The system of claim 149, wherein the filter elements each comprise a filter having a wavelength dependent optical transmission property.

155. The system of claim 149, wherein the filter elements each comprise a cut-off filter element.

156. The system of claim 149, wherein the plurality of filter elements comprise a color gradient filter or a filter grid.

157. The system of claim 149, wherein light received by the optical sensors is spectrally analyzed without using a diffraction grating.

158. The system of claim 149, wherein a probe having one or more light sources provides light to the substrate.

159. The system of claim 158, wherein one or more sensors determine a distance and/or angle of the probe with respect to the substrate.

160. The system of claim 149, wherein each of the signals having a frequency proportional to the light intensity received by the particular sensor is generated by an integrator coupled to or integrated into the particular sensor.

161. The system of claim 103, wherein one or more processing elements comprise a microprocessor, logic, a logic array or a programmable logic array.