A system comprising: an infrared projector; a pattern mask located in an output path of the infrared projector; a stereoscopic camera to generate images of opposing pages of a document from which a three-dimensional image of a surface of the opposing pages of the document is generated; and control logic to process the three-dimensional image to locate a groove that is defined by the spine of the document and located between the opposing pages of the document.
The patent is based on application 10/938,727, filed 13 Sept 2004. It is not clear that there is a corresponding published application. This would suggest that there will NOT be ANY foreign counterpart patents to the '978 (and people would be free to use the system OUTSIDE the US!). Further, there was an amendment AFTER notice of allowance on 18 Dec 2008.
from CNET news:
Sometimes overlooked in the Sturm und Drang about Google Book Search is any consideration of the mechanics of economically scanning the books in the first place, but a patent awarded to Google gives insight into how the search behemoth accomplishes the task.
In short, Google has come up with a system that 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.