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How Google's High Speed Book Scanner De-Warps Pages
Hugh Pickens writes "Patent 7,508,978, awarded to Google, shows how the company has already managed to scan more than 7 million books. Google's system uses two cameras and infrared light to automatically correct for the curvature of pages in a book. By constructing a 3D model of each page and then 'de-warping' it afterward, Google can present flat-looking pages online without having to slice books up or mash them onto a flatbed scanner. Stephen Shankland writes that the 'sophistication of the technology illustrates that would-be competitors who want to feature their own digitized libraries won't have a trivial time catching up to Google.' First, a book is placed on a flat surface, while above it, an infrared projector displays a special mazelike pattern onto the pages. Next, two infrared cameras photograph the infrared pattern from different perspectives. 'The images can be stereoscopically combined, using known stereoscopic techniques, to obtain a three-dimensional mapping of the pattern,' according to the patent. 'The pattern falls on the surface of (the) book, causing the three-dimensional mapping of the pattern to correspond to the three-dimensional surface of the page of the book.'"
When is the patent office going to quit giving patents for obvious techniques? :)
How long before some particularly vengeful luddite publisher starts printing on treated paper stock that has an IR visible pattern, calculated to confuse these scanners, printed on it?
They've been making "anti-copy paper" designed to defeat optical scanning for years now, surely something similar in the IR band could be effected...
but to be honest this is at least worthy patent
-- if you mod me down, I will become more powerful than you can possibly imagine
That's modded funny, but take a look at this.
Maybe they use automated page turning machines for normal books, and turn pages by hand for older/more fragile works?
"Anyone who [rips a CD] is probably engaging in copyright infringement." - David O. Carson
Word.
I was involved in evaluating rare books back around the turn of the century.
I can personally attest that representatives of online book search companies were attempting to buy up one of a kind pieces for destructive scanning.
There was one dealer in possession of a somewhat flawed, but well examined Shakespeare folio that had to put the kabosh on a reputation making deal because he found out the buyer was going to slice the piece out of its binding for scanning.
I turned down a much smaller offer on a much less significant, but still very cool, two hundred year old angler's guide (with hand colored plates and original binding) for the same reason.
Quality scans without destruction can only help raise the profile of rare books and the value they offer society - not simply for their content, but as tangible examples of the evolution of the art of communication.
This trick has been used for 20 years in astronomy. You shine a really powerful laser of known metrics into the sky and measure the atmospheric distortion suffered by the beam.
Then you take those numbers and calculate what it would take to even out the beam, and you feed THAT set of numbers to a telescope with adaptive optics which will then correct for the atmospheric distortion. Bingo, suddenly your telescope is able to take sharp images without having the air screw it up.
The technique is very effective and results in ground-based telescopes that rival anything the Hubble can do. Plus they are easier to fix.
I want to say this is called Guidestar but I am not sure.
Anyway the similarity to Google's process is simply that you shine a light or image of known value on something unknown and look at how the image now deviates from what you expect. A little math and suddenly you know exactly the shape of the unknown object. Brilliant.