How does CamScanner, Genius Scan, and JotNot work? [closed]

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Improve this question 开发者_如何学JAVA

I was looking at CamScanner, Genius Scan, and JotNot and trying to figure out how they work.

They are known as 'Mobile Pocket Document Scanners.' What each of them do is take a picture of a document through the iPhone camera, then they find the angle/position of the document (because it is nearly impossible to shoot it straight on), straightens the photo and readjusts the brightness and then turns it into a pdf. The end-result is what looks like a scanned document.

Take a look here of one of the apps, Genuis Scan, in action: http://www.youtube.com/watch?v=DEJ-u19mulI

It looks pretty difficult to implement but I'm thinking someone smart on stackoverflow can point me in the right direction!

Does any know how one would go about developing something like that? What sort of library or image processing technologies do you think they're using? Anyone know if there is something open source that is available?

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I found an open source library that does the trick:

http://code.google.com/p/simple-iphone-image-processing

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It probably is pretty difficult, and you will likely need to find at least some algorithms or libraries capable of detecting distorted text within bitmaps, analyzing the likely 2D and 3D geometric distortion within a text image, image processing to correct that distortion with its inverse, and DSP filtering to adaptively adjust the image contrast... plus use of iOS APIs to take photos in the first place.