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US 6,556,932 B1Granted
System and method for reconstruction of spectral curves using measurements from a color sensor and a spectral measurement system model
AssigneeXerox Corporation
InventorsLingappa K. Mestha, Yao Wang, Fred F. Hubble, III, Tonya L. Love
Life of this patent
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Abstract
By using a reconstruction algorithm, based on the spectral characteristics of the illumination source and a color sensing system, a spectral curve reconstruction device converts measurements from a non-fully illuminant populated color sensor into a fully populated spectral curve. This is done using a spectral measurement system model, which may use basis vectors.
Claims15
A spectral reconstruction system comprising:
- a spectral characteristic determination device that determines a reflectance spectra of a substrate from at least one illumination device and a spectral measurement system model, the spectral measurement system model being defined as:
- V i = k i ∫ 0 τ i ∫ λ min λ max S i ( λ ) R ( λ ) D ( λ ) ⅆ λ ⅆ τ + V i o ,
- where, for an ith illumination device, τi is an integration time for an illumination device switching event, Vi is a measure of the amount of integrated light flux at the output of a detector circuit, Vio is a sensor offset, ki is a scaling factor, R(λ) is a collective reflectance spectra of a color, D(λ) is a detector spectral response, and Si (λ) is a spectra of the ith illumination device.
A spectral reconstruction method comprising:
- determining a reflectance spectra of a substrate from at least one illumination device and a spectral measurement system model, the spectral measurement system model being defined as:
- V i = k i ∫ 0 τ i ∫ λ min λ max S i ( λ ) R ( λ ) D ( λ ) ⅆ λ ⅆ τ + V i o ,
- where, for an ith illumination device, τi is an integration time for an illumination device switching event, Vi is a measure of the amount of integrated light flux at the output of a detector circuit, Vio is a sensor offset, ki is a scaling factor, R(λ) is a collective reflectance spectra of a color, D(λ) is a detector spectral response, and Si (λ) is a spectra of the ith illumination device.
A spectral reconstruction system comprising:
- a spectral characteristic determination device that determines a reflectance spectra of a substrate from at least one illumination device and a spectral measurement system model that is based on an integration time for an illumination device switching event, a measure of the amount of integrated light flux at the output of a detector circuit, a collective reflectance spectra of a color, a detector spectral response, and a spectra of an illumination device.
Dependencies are inferred from the claim text.