The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 21, 1999
Filed:
Aug. 29, 1997
Edward M Granger, Rochester, NY (US);
X-Rite, Incorporated, Grandville, MI (US);
Abstract
A technique for calibrating a scanner wherein once the scanner is calibrated, the scanner's device-dependent tristimulus values (e.g., RGB) for an arbitrary color are transformed to a device-independent representation (e.g., XYZ) of the arbitrary color in a computationally efficient manner. The scanner is characterized in a manner that a corrected device-independent representation of an arbitrary scanned color can be determined on the basis of a pair of chromaticity coordinates in a chromaticity space having (i) a pair of chromaticity coordinates that span hue and chroma (saturation), and (ii) a lightness coordinate that is a luminance correlate (monotonic function of luminance). A look-up table stores XYZ values and a lightness value. A set of XYZ values and a lightness value are retrieved from the table as addressed by a pair of chromaticity values corresponding to the scanned value. The XYZ values from the table are then scaled by the ratio of the scanned lightness value to the lightness value from the table to provide the XYZ values for the arbitrary color.