As any student with a research project probably knows, copying pages from a book at Kinko's
-- or anyplace else -- can be book-breaking work.
say they have a way to take the kinks out of Kinko's with a new computerized
copier program that makes picture-perfect copies of pages from bound books
without damaging their spines.
Hitting the Books Softly
"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
"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."
The result: a poor-quality copy that previous, expensive solutions have never much improved.
"The remote-sensing community has been applying image warping to invert geometric
distortions induced by lens aberrations and viewing geometry for four decades,"
said Wolberg, who authored Digital
, a leading text on image warping and morphing.
Xerox even tried correcting for warped images -- with mixed results.
"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
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.
"This work is unique in that it is driven by illumination and the
geometric optics model," Wolberg told NewsFactor. "The latter addresses the
magnification that is based on distance from the platen."
Better Read than Dead
Some people worry that reading books is a dying art, but consumers
still read books by the ream, and it is mainly for them that Xerox pioneered
the new book-scanning technology.
"The software is designed to work with the methodology that is commonly
used in consumer market scanners and copiers," Loce said.
But bookish Web giants, such as Amazon and Google, may also benefit.
"Google has announced plans to digitize a large collection of books
and has formed associations with several key libraries for the purpose of
bringing online a vast wealth of books that are currently offline," Wolberg
explained. "Any book-scanning technology must address digital correction
of warped pages of text."
The Xerox researchers presented the new scanning technology at the 5th International Conference on Imaging Science and Hard Copy last month in Xi'an, China.