Re: Page images of books (using a digital camera)
- From: Ron Gustavson <rongusss@[redacted]>
- Subject: Re: Page images of books (using a digital camera)
- Date: Wed, 07 Mar 2001 11:20:30 -0500
On Tue, 6 Mar 2001 17:15:32 -0500, "Harry Plantinga" wrote:
>The results aren't quite as good. There are two basic problems to deal
>with: lighting variation and geometric distortion. Also, the images may
>be a bit less sharp, especially if lighting is inadequate. (We're still
>tweaking the algorithm too.)
>
>We have an algorithm for making a nice bitonal image out of a page picture
>using local contrast thresholds, so the lighting variation isn't a problem
>for
>OCR. However, you'd have to do something different to correct illustrations.
>We're also working on an algorithm to correct geometric distortion inherent
>in the process (since some parts of the page are farther from the camera
>than other parts, and pages don't lie entirely flat).
A copy stand would help with both these issues.
In the past I've used an old photo enlarger, as it was taller
than a real copy stand, and could be used with a camcorder that
wouldn't focus as close as a 35mm camera. To do a proper job, a
macro lens would be ideal to focus on a flat plane, but I don't know
of any digital cameras that accomodate one, save the Nikon D1.
__________NO-∞-DO__________