Hewlett-packard Development Company, L.p.

Jorge Miguel Gomez Lucia

Justin M Roman

David M Berfanger

John Mark Hatcher

Hosein Ali Razavi

Russell Fredrickson

John Andrew Bryson

Example implementations relate to PRNU suppression. For example, PRNU suppression may include performing a calibration surface PRNU characterization using a scanning system, performing a document-based PRNU characterization using the scanning system, and determining a correction function for PRNU suppression for the scanning system based on the calibration surface PRNU characterization and the document-based PRNU characterization.

Photo response non-uniformity suppression

In one example, a document scanner having a document-receiving platen. The platen includes a plurality of alignment patterns disposed on the platen at known positions in a coordinate system. The scanner includes overlapping staggered scan bars disposed adjacent the platen, each scan bar fixed at a position to image a one-dimensional slice of a corresponding one of the alignment patterns. The scanner further includes a controller to determine, from the imaged slice, X and Y coordinates of each corresponding scan bar within the coordinate system.

Determining coordinates of scan bars

According to an example, an apparatus for controlling a media scan operation may include a first scan module to scan a section of a media, a tracking mechanism to track the media as the media is moved past the first scan module, and a controller. The controller may receive signals corresponding to the media movement from the tracking mechanism, determine, based upon the received signals, a current position of the media, and vary a timing at which the first scan module collects a scan of the section of the media based upon the determined current position of the media.

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Vancouver, WA, United States of America

Jorge Miguel Gomez Lucia