Unisys Corporation

Karen A Wilds

Robert D Klein

Michael J Higgins-Luthman

David C Williams

Debora Y Grosse

A digital image preprocessing method for eliminating background patterns and scenes from digitized gray level document image data. The method accepts multi-gray level image data as input and produces a gray level output image containing a 'white' background. Document image backgrounds are eliminated (or suppressed) by computing a separate (and typically different) threshold value for each gray level pixel of the original document image. Input image pixels whose gray level is greater (brighter) than the threshold value are assumed to be background picture data and are modified to be 'white' pixels in the output image. The pixel threshold value is determined dynamically pixel-to-pixel based on gray level pixel data observed within the input image. Additionally, the pixel threshold can be automatically controlled to insure retention of written and/or printed information present in the input image. Threshold control is accomplished by specifying a print contrast signal (PCS) parameter to the image preprocessing method. Documents which might use this preprocessing technique include, but are not limited to, bank checks, remittance documents, charge card slips, deposit slips and similar type financial documents.

Method for background suppression in an image data processing system

A method and apparatus featuring the compression and decompression of the video image data on a single application specific integrated circuit (ASIC) which utilizes typical Huffman coding techniques, but which defines a run count generally as a plurality of zeros between each pair of ones and which further uses a prediction window having substantially no directional biasing errors associated therewith. Additionally, the compression/decompression apparatus of this invention utilizes a reordering technique whereby all of the 'high confidence' predictions are placed in one end of the buffer and all the 'low confidence' predictions are placed in another end of the same buffer. This reordering, together with the unbiased window configuration and associated run length count definition, allows for high efficiency lossless compression and decompression of associated image data.

Growing community of inventors

Plymouth, MI, United States of America

Karen A Wilds