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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.'"
But who turns the page?
Reviewing just the first hour of video games.
Actually this isn't new. Back in college, around 1993-1994 I was working with a team that used stripe lasers projected forward from a vehicle. Then a pair of stereoscopic cameras would take a picture. Then software would analyze the deflection in the beams to determine the shape of terrain the vehicle was approaching. In fact the information from the previous images was translated through the system's model of the terrain as the vehicle moved around. It was quite clever.
One might check this paper (I am not the author of the paper):
http://tim.mcjunkin-web.org/mcjunkin_thesis_body.pdf