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Browse Prior Art Database

Sequential Image Data Compression

IP.com Disclosure Number: IPCOM000116675D
Original Publication Date: 1995-Oct-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Ueda, H: AUTHOR

Abstract

A program is disclosed that a pre-processing program for lossless image data compression and decompression applied to a printer that has a page data buffer such as a laser printer. The program generates the correlation of consecutive page image data before lossless data compression to remove identical digitized image data in consecutive print pages. The program also calculates the correlation with previous page image data after lossless data decompression to restore the original digitized image data.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 68% of the total text.

Sequential Image Data Compression

      A program is disclosed that a pre-processing program for
lossless image data compression and decompression applied to a
printer that has a page data buffer such as a laser printer.  The
program generates the correlation of consecutive page image data
before lossless data compression to remove identical digitized image
data in consecutive print pages.  The program also calculates the
correlation with previous page image data after lossless data
decompression to restore the original digitized image data.

      An n-th page image data:  "Page(n)" consist of series of data
bytes or words that represents a digitized page image.  A previous
page image data:  "Page(n-1)".  consist of the same data structure as
the "Page(n)".  The n-th data byte or word in the "Page(n-1)"
represents the same coordinates of the digitized image as in the
"Page(n)".  When the "Page(n)" is the first page, the "Page(n-1)" may
be represented by a blank page.

      To generate the lossless compressed page image data, the
program generates the data "X-Page(n)" that consist of the result of
exclusive-or operation between the "Page(n-1)" and the "Page(n)" in
the order of byte or word.  The identical digitized image data in the
"Page(n)" and the Page(n-1)" are removed in the "X-Page(n)".

      "C(X-Page(n))":  the result of a lossless data compression is
performed on the "X-Page(n)" is expected to be smaller than
"C(Page(n))":  the result o...