Hewlett-packard Development Company, L.p.

Purdue Research Foundation

Runzhe Zhang

Jan Philip Allebach

Mark Q Shaw

Richard Eric Maggard

Renee Jeanette Jessome

Yousun Bang

Minki Cho

Yi Yang

According to examples, an apparatus may include a processor and a memory on which are stored computer-readable instructions that, when executed by the processor, may cause the processor to access a master image to be printed and receive a scanned image corresponding to the master image. The processor may identify a defect in a scanned image region of interest (ROI) based on the master image. A type of the scanned image ROI may include a raster ROI, a symbol ROI, a background ROI, and/or a color vector ROI, and the identified defect may be associated with the type of the scanned image ROI. The processor may determine a severity of the identified defect of the scanned image and may output the determined severity.

Image region of interest defect detection

In an example method, an image of a printed document is descreened. The descreened image is separated into blocks. A smooth area of the descreened image is selected based on an averaging of localized color distance values of pixels in each of the blocks. A streak in a block of the smooth area is detected in response to detecting that a magnitude of a color distance projection of the block exceeds a threshold value.

Detecting streaks in printed documents using blocks

Growing community of inventors

West Lafayette, IN, United States of America

Runzhe Zhang