Translatable scanner calibration target
AssigneeHewlett-Packard Development Company, L.P.
InventorsWesley R. Schalk, Al Olson, Justin M. Roman, Jeffrey G. Bingham, Dennis J. Schissler, Andrew T. Davis
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Abstract
In one example, a document scanner has a fixed-position scan bar and a built-in translatable calibration target. The scan bar has a linear array of imaging elements aimed in an imaging direction. The calibration target is spaced apart from and parallel to the linear array, and has a planar surface orthogonal to the imaging direction spanning the length of the linear array. The target is translatable during a calibration in a direction in a plane of the surface.
Claims15
A document scanner, comprising:
- a fixed-position scan bar having a linear array of imaging elements aimed in an imaging direction;
- and
- a built-in translatable calibration target spaced apart from and parallel to the linear array of imaging elements, the target having a planar surface orthogonal to the imaging direction and spanning the length of the linear array, and the calibration target translatable in a direction that is in a plane of the planar surface and orthogonal to the imaging elements during a calibration operation including an imaging of the calibration target.
A method of calibrating a document scanner without a calibration document, comprising:
- controllably moving a flat translatable calibration target built into the document scanner a predetermined distance relative to a fixed-position scan bar of the scanner;
- during the moving, repeatedly imaging the calibration target with the fixed-position scan bar such that each imaging element of the fixed-position scan bar captures signals for a zone of a flat uniform color surface of the calibration target;
- and
- processing the captured signals from each imaging element to calibrate the scanner.
A document scanner, comprising:
- a scan bar array of overlapping staggered fixed-position scan bars each having a linear array of imaging elements;
- an array of overlapping staggered calibration targets translatable during a calibration operation and spaced apart from and parallel to the scan bar array, each target having a planar surface that spans a length of a corresponding imaging element array and is imageable by the imaging elements of a corresponding linear array;
- and
- a single drive system coupled to all the calibration targets to controllably translate the calibration targets relative and orthogonal to the fixed-position scan bars during the calibration operation.
Dependencies are inferred from the claim text.