Colorimeter and calibration system
First Claim
1. A color measurement device for determining the color composition of a small predetermined area at an arbitrary position on an object having an exposed surface, the apparatus comprising:
- a variable wavelength light filter having a light-receiving surface, to receive an incident light beam from the object, the light having a plurality of wavelengths in a selected wavelength band, and to disperse the beam into a plurality of four or more narrow, non-overlapping wavelength pass bands, each pass band having a wavelength width no more than 20 nm, with a central wavelength λ
c (x) that increases monotonically with an increase of a position coordinate x measured in a selected direction lying on the light-receiving surface;
light restriction means that defines a small predetermined area for receiving and admitting light from a restricted portion of the object and for directing this light to the light-receiving surface of the light filter, where the light restriction means comprises a window that approximately coincides with the small predetermined area and has a first area transparent to light in the selected wavelength band and has a second area surrounding the first area that is substantially opaque to light in the selected wavelength band;
an array of photosensors, positioned to receive light that is transmitted through or reflected from the light filter so that each photosensor in the array receives light in a very narrow band of wavelengths having the central wavelength λ
c (x) and having a wavelength width no more than a wavelength width of a pass band of the light filter, for light received or transmitted at the position with coordinate x on the light filter, with each photosensor in the array issuing an output signal that represents the cumulative light energy received by that photosensor from the light filter; and
color measurement means for receiving the photosensor output signals and for determining the color or colors present in the incident light based on the relative amounts of light of different wavelengths received at four or more of the photosensors.
2 Assignments
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Accused Products
Abstract
Apparatus for monitoring, converting and calibrating the spectra displayed by a colored object, using wavelength dispersion provided by a variable wavelength filter. The apparatus may serve as a spectrophotometer, as a colorimeter, or as a spectroradiometer or other device that monitors and calibrates a light signal by decomposition of the signal into a wavelength distribution. The apparatus may also be used as part of a feedback network to monitor and correct colors displayed by a color monitor, color printer, color scanner or other similar peripheral device controlled by a computer that is part of the network.
393 Citations
28 Claims
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1. A color measurement device for determining the color composition of a small predetermined area at an arbitrary position on an object having an exposed surface, the apparatus comprising:
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a variable wavelength light filter having a light-receiving surface, to receive an incident light beam from the object, the light having a plurality of wavelengths in a selected wavelength band, and to disperse the beam into a plurality of four or more narrow, non-overlapping wavelength pass bands, each pass band having a wavelength width no more than 20 nm, with a central wavelength λ
c (x) that increases monotonically with an increase of a position coordinate x measured in a selected direction lying on the light-receiving surface;light restriction means that defines a small predetermined area for receiving and admitting light from a restricted portion of the object and for directing this light to the light-receiving surface of the light filter, where the light restriction means comprises a window that approximately coincides with the small predetermined area and has a first area transparent to light in the selected wavelength band and has a second area surrounding the first area that is substantially opaque to light in the selected wavelength band; an array of photosensors, positioned to receive light that is transmitted through or reflected from the light filter so that each photosensor in the array receives light in a very narrow band of wavelengths having the central wavelength λ
c (x) and having a wavelength width no more than a wavelength width of a pass band of the light filter, for light received or transmitted at the position with coordinate x on the light filter, with each photosensor in the array issuing an output signal that represents the cumulative light energy received by that photosensor from the light filter; andcolor measurement means for receiving the photosensor output signals and for determining the color or colors present in the incident light based on the relative amounts of light of different wavelengths received at four or more of the photosensors. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A color measurement system for monitoring and controlling the spectrum of colors presented by one or more computer peripheral devices controlled by a computer, the apparatus comprising:
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a variable wavelength light filter having a light-receiving surface, to receive an incident light beam from the peripheral device, the light having a plurality of wavelengths in a selected wavelength band, and to disperse the beam into a plurality of four or more narrow, non-overlapping, wavelength pass bands, each pass band having a wavelength width no more than 20 nm and having a central wavelength λ
c (x) that increases monotonically with an increase of a position coordinate x measured in a selected direction lying on the light-received surface;light restriction means that defines a small predetermined area for receiving and admitting light from a restricted portion of the object and for directing this light to the light-receiving surface of the light filter; an array of photosensors, positioned to receive light that is transmitted through or reflected from the light filter so that each photosensor in the array receives light in a very narrow band of wavelengths, with each such band having a central wavelength λ
c (x) and having a wavelength width no more than the wavelength width of a pass band of the light filter, for light received and dispersed at the position with coordinate x on the light filter, with each photosensor in the array issuing an output signal that represents the cumulative light energy received by that photosensor from the light filter;color measurement means for receiving the photosensor output signals and for determining the color or colors present in the incident light based on the relative amounts of light of different wavelengths received at four or more of the photosensors; and light calibration means for receiving the output signals from the photosensor array, for comparing the amount of light received by the photosensors in the array with a reference table of light values that should be received by each of the photosensors, or by a linear combination of at least two of the photosensors, and for generating and issuing a sequence of output signals that indicates the difference between, or the ratio R of, the reference table entry for a photosensor, or combination thereof, and the amount of light actually received by that photosensor, or a combination thereof, in the array; where the light calibration means output signals are received by the computer and, in response thereto, the computer adjusts color data signals that are received by or rendered by the computer peripheral devices, to reduce the difference between the reference table entries and the corresponding output signals from the color measurement means.
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16. A color calibration system for monitoring and controlling the spectrum of colors presented by one or more computer peripheral devices controlled by a computer, the system comprising:
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a variable wavelength light filter having a light-receiving surface, to receive an incident light beam from the peripheral device, the light having a plurality of wavelengths in a selected wavelength band, and to disperse the beam into a plurality of four or more narrow, non-overlapping wavelength pass bands, each pass band having a wavelength width no more than 20 nm, with a central wavelength λ
c (x) that increases monotonically with an increase of a position coordinate x measured in a selected direction lying on the light-receiving surface;light restriction means that defines a small predetermined area for receiving and admitting light from a restricted portion of the peripheral device and for directing this light to the light-receiving surface of the light filter, where the light restriction means comprises a window that approximately coincides with the small predetermined area and has a first area transparent to light in the selected wavelength band and has a second area surrounding the first area that is substantially opaque to light in the selected wavelength band; an array of photosensors, positioned to receive light that is transmitted through or reflected from the light filter so that each photosensor in the array receives light in a very narrow band of wavelengths having the central wavelength λ
c (x) and having a wavelength width no more than a wavelength width of a pass band of the light filter, for light received or transmitted at the position with coordinate x on the light filter, with each photosensor in the array issuing an output signal that represents the cumulative light energy received by that photosensor from the light filter; andcolor measurement means for receiving the photosensor output signals and for determining the color or colors present in the incident light based on the relative amounts of light of different wavelengths received at four or more of the photosensors, wherein the color measurement means is operatively associated with a remote imaging device and associated remote imaging device light source that produces and renders a color image of the object, and the apparatus includes remote device spectrum adjustment means for compensating for the wavelength distribution of light emitted by the remote imaging device light source relative to the wavelength distribution of a selected light source. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A color measurement device for determining the color composition of a small predetermined area at an arbitrary position on an object having an exposed surface, the apparatus comprising:
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a variable wavelength light filter having a light-receiving surface, to receive an incident light beam from the object, the light having a plurality of wavelengths in a selected wavelength band, and to disperse the beam into a plurality of narrow wavelength pass bands, with each pass band having a wavelength width of no more than 20 nm and having an central wavelength λ
c (x) that increases monotonically with an increase of a position coordinate x measured in a selected direction lying on the light-receiving surface;light restriction means that defines a small predetermined area for receiving and admitting light from a restricted portion of the object and for directing this light to the light-receiving surface of the light filter; an array of photosensors, positioned to receive light that is transmitted through or reflected from the light filter so that each photosensor in the array receives light in a very narrow band of wavelengths having the central wavelength λ
c(x) and having a wavelength width no more than a wavelength width of a pass band of the light filter, for light received and dispersed at the position with coordinate x on the light filter, with each photosensor in the array issuing an output signal that represents the cumulative light energy received by that photosensor from the light filter; andcolor measurement means for receiving the photosensor output signals and for determining the color or colors present in the incident light based on the relative amounts of light or different wavelengths received at four or more of the photosensors.
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28. A color measurement system for monitoring and controlling the spectrum of colors presented by one or more computer peripheral devices controlled by a computer, the apparatus comprising:
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a variable wavelength light filter having a light-receiving surface, to receive an incident light beam from the peripheral device, the light having a plurality of wavelengths in a selected wavelength band, and to disperse the beam into a plurality of narrow wavelength pass bands, with each pass band having a wavelength width of no more than 20 nm and having a central wavelength λ
c (x) that increases monotonically with an increase of a position coordinate x measured into a selected direction lying on the light-receiving surface;light restriction means that defines a small predetermined are for receiving and admitting light from a restricted portion of the object and for directing this light to the light-receiving surface of the light filter; an array of photosensors, positioned to receive light that is transmitted through or reflected from the light filter so that each photosensor in the array receives light in a very narrow band of wavelengths, with each such band having a central wavelength λ
c (x) and having a wavelength width no more than the wavelength width of a pass band of the light filter, for light received and dispersed at the position with coordinate x on the light filter, with each of at least seven photosensors in the array issuing an output signal that represents the cumulative light energy received by that photosensor from the light filter;color measurement means for receiving the photosensor output signals and for determining the color or colors present in the incident light based on the relative amounts of light of different wavelengths received at seven or more of the photosensors; and light calibration means for receiving the output signals from the photosensor array, for comparing the amount of light received by the photosensors in the array with a reference table of light values that should be received by each of the photosensors, or by a linear combination of at least two of the photosensors, and for generating and issuing a sequence of output signals that indicates the difference between, or the ratio R of, the reference table entry for a photosensor, or combination thereof, and the amount of light actually received by that photosensor, or a combination thereof, in the array; where the light calibration means output signals are received by the computer and, in response thereto, the computer adjusts color data signals that are received by or rendered by the computer peripheral devices, to reduce the difference between the reference table entries and the corresponding output signals from the color measurement means.
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Specification