Hewlett-packard Development Company, L.p.

Hosein Ali Razavi

David M Berfanger

John Mark Hatcher

Jorge Miguel Gomez Lucia

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

An illumination source comprises a plurality of groups of serially-coupled light emitting diodes (LEDs). The LEDs in each group have an emission-spectrum that is common to that group. At least one group has a different emission-spectrum from at least one other group and at least one group of LEDs has a different number of LEDs than at least one other group.

Illumination source comprising a plurality of light emitting diode groups

An illumination source for a scanner comprises a plurality of terminals and a plurality of light emitting diodes (LEDs) with at least two LEDs having different wavelengths. Each LED is coupled to a terminal and each LED is capable of being turned on and off via a signal provided to a terminal to which that LED is coupled. The number of LEDs is greater than the number of terminals.

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San Diego, CA, United States of America

Hosein Ali Razavi