[DigiCam] Re: DigiCam for OCR

[dennisfey at attbi.com]

Thanks for the guidelines.  I get confused about determining my resolution 
requirement, because I work with just 2-bit (black/white) TIFF images, 
which at 300dpi scanning are at no more than 100Kbytes 
each.  Unfortunately, digicam mfr. specs appear dedicated to informing you 
about the camera's capacity for 16bit+ color depth TIFF images, which are 
very data intensive.

Now, only 300dpi is acceptable for my OCR.  Converting this to my 
resolution requirement for a digicam gets me mucked up.   If I'm scanning a 
8.5x11 page at 300dpi, this appears to be equivalent to 2550 pixels X 3300 
pixels.  Now, this might mean I need a 8 million+ digicam for 16-bit color 
shots, printable at 300dpi, but surely it doesn't mean I need that for 
shooting 2-bit, b/w, 300dpi-equivalent TIFFs!

How do I determine my resolution requirement at 2-BIT (b/w), NOT 16-BIT 
color depth?

Dennis

At 10:17 AM 6/1/2003 -0700, you wrote:
>A few things I would consider:
>
>To determine the resolution you will need, try to determine the ratio of the
>smallest type to largest page you will be photographing - 8 point on a 3
>inch page doesn't require as much resolution as 11 point on a 12 inch page.
>You can determine the total resolution you need by scanning a page at
>different resolutions and seeing the pixel dimensions that give acceptable
>results - if they are 1,200 X 1,600 pixels, then a 2 megapixel camera would
>theoretically meet your needs (1,200 X 1,600 = 1.92 MP).
>
>Another thing you may want to consider is if you will be doing any macro
>photography. Are any of the books very small? If so, you may want to compare
>how closely different cameras will focus.
>
>As to TIFF images - many cameras offer saving images in a TIFF format.
>However, many software applications can easily convert your JPEG images to
>TIFF - you would just need to be sure that you don't over-compress the
>JPEGs.
>
>It would probably make sense to make a Photoshop Action (or other
>automation) that converted the image to a grayscale TIFF. This would allow
>this to happen in the background, while you do other things, or during
>lunch, etc.
>
>If I were looking for a camera to do what you are doing, I would probably
>look at the Nikon line (the 4700 or even a used 990 or 995) - very sharp
>images, ability to save in TIFF (if you determine that is your preference),
>great macro capabilities, etc. The only weakness is that they don't focus
>well in low light - but that probably isn't a factor for your application.
>
>Good luck,
>
>George Reis
>--
>Imaging Forensics <http://www.imagingforensics.com>
>Specializing in digital imaging consulting, training, analysis and
>enhancement for the law enforcement, investigative and legal communities.
>
>
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