| US 7,589,837 B2 | ||
| Multiple tile calibration method for color sensors | ||
| Yao Rong Wang, Webster, N.Y. (US); Lalit Keshav Mestha, Fairport, N.Y. (US); Peter Michael Gulvin, Webster, N.Y. (US); and Pinyen Lin, Rochester, N.Y. (US) | ||
| Assigned to Xerox Corporation, Norwalk, Conn. (US) | ||
| Filed on Dec. 01, 2006, as Appl. No. 11/606,985. | ||
| Prior Publication US 2008/0130009 A1, Jun. 05, 2008 | ||
| Int. Cl. G01J 3/46 (2006.01) | ||
| U.S. Cl. 356—402 [250/252.1] | 18 Claims |
| 1. A method for calculating a scaling factor for a sensor, comprising:
(a) providing a white tile with known reflectance Rw(λ) over a spectra having wavelengths λ;
(b) providing two or more color tiles with known reflectance Ri(λ) over said spectra;
(c) obtaining, via the sensor, measurements Vw(λ) for the reflectance of said white tile at each wavelength of said spectra;
(d) obtaining, via the sensor, measurements Vi(λ) for the reflectance of each of said color tiles at each wavelength of said spectra;
(e) calculating a wavelength dependent adjustable constant A(λ) for each wavelength of said spectra as a function of Rw(λ) and Vw(λ) for said white tile and Ri(λ) and Vi(λ) for each of said color tiles; and
(f) calculating a scaling factor f(λ) for each wavelength of said spectra, as follows:
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