The E-Sylum:  Volume 7, Number 52, December 26, 2004, Article 3

XEROX RESEARCH COULD END SPINE-CRUSHING PHOTOCOPYING

  A software solution from Xerox labs, announced last month 
  at a conference in Xi'an, China, may hold a part of the 
  solution to Google's daunting book-scanning problems, and
  should delight librarians and researchers as well.  From
  a recent article:

  "If you've ever copied pages from a book, you're familiar
  with the problem -- dark, distorted words where the page 
  is bound into the book," said Xerox spokesperson Bill 
  McKee. "To correct it, most of us use the 'brute force' 
  method for getting readable copies -- pushing the book to
  flatten it against the glass scanning surface, called the
  platen." 

  Library science 101 at the elementary grade level   
  emphasizes one point above all else -- don't bend the book
  and damage the spine.  Xerox researchers Beilei Xu and 
  Robert Loce have proposed a simple solution that should 
  make librarians everywhere stand up and cheer -- a 
  mathematical formula incorporated in the software of 
  common scanners that eliminates the book-breaking problem. 

  "The programming of a mathematical algorithm to correct 
  for the book's warped appearance on a copy machine will 
  work," said City College of New York computer science 
  professor George Wolberg. "The challenge is to find the 
  spatial transformation that accurately models the distortion, 
  and this is precisely where the Xerox method excels." 

  "When a book page is not in uniform, intimate contact with 
  the scanning surface, there are actually two distinct 
  problems," Loce explained. "The variation in illumination 
  causes some portions of the copy to be darker than others, 
  and the variation in distance from the scanning surface 
  causes letters or objects farther from the surface to look
  warped." 

  "At one time, Xerox sold a copier with an angled edge and 
  articulated cover so people could copy pages without 
  cracking books all the way open," McKee told NewsFactor. 
  "Another solution is dedicated book scanners with height 
  sensors, so the book lies face up, and scanning takes 
  place from above it." 

  Instead of changing the hardware, Xu and Loce decided to 
  look at an easier solution. 

  They changed the software, inexpensively. 

  "Since the Xerox solution requires no special apparatus and
  all corrections are based solely on the digital image itself,
  this has huge implications on cost. It can be applied 
  directly on very low-cost scanners," Wolberg explained. 

  Using the same light that copy scanners shine and analyze, 
  "we use the sensed light to also determine the distance of
  the book from the platen for each pixel on the page," Xu 
  told NewsFactor. "Normally the light only provides 
  information on the reflectance of the original document." 

  The new copier software mathematically compensates for 
  variation in distance from the platen along a bound book 
  page. 

  It eliminates the darker portion of the copy where the 
  page is bound into the book and "de-warps" the normally
  distorted words running along the center of the page."

  To read the full article, see: Full Story

  Wayne Homren, Editor

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