Translatable scanner calibration target
AssigneeHewlett-Packard Development Company, L.P.
InventorsWesley R Schalk, Al Olson, Justin M Roman, Jeffrey G Bingham, Dennis Schissler, Andrew T Davis
Life of this patent
Estimating the term…
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.
Claims12
A document scanner, comprising:
- a fixed-position scan bar having a linear array of imaging elements aimed in an imaging direction;
- a built-in translatable calibration target spaced apart from and parallel to the linear array, the target having a planar surface orthogonal to the imaging direction and spanning the length of the linear array, and the target translatable during a calibration in a direction in a plane of the surface,
- a compliant bias plate having the calibration target;
- and
- a resilient member to urge the compliant bias plate toward the linear array.
A method of calibrating a document scanner without a calibration document, comprising:
- controllably moving a flat translatable calibration target built into the 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;
- after the processing:
- returning the calibration target to an initial position;
- feeding a document through the scanner between the fixed-position scan bar and the calibration target;
- during the feeding, sequentially imaging strips of the document with the fixed-position scan bar with the calibration target in the initial position;
- and
- processing the imaged strips to construct a digital representation of the document.
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 translatable calibration targets 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 the corresponding linear array;
- and
- a single drive system coupled to all the calibration targets to controllably translate the calibration targets relative to the scan bars during a calibration operation, and
- wherein the single drive system comprises:
- a rotatable cam shaft;
- a plurality of cams each fixed to the cam shaft at an angular position;
- and
- a plurality of cam engagement features each coupled to a corresponding one of the calibration targets and engaged with a corresponding one of the cams.
Dependencies are inferred from the claim text.