Daniel Reetz, the founder of the DIY Book Scanner community, has recently started making videos of prototyping and shop tips. If you are tinkering with a book scanner (or any other project) in your home shop, these tips will come in handy. https://www.youtube.com/channel/UCn0gq8 ... g_8K1nfInQ

Math, Measurements, Ratios

Everything camera related. Includes triggers, batteries, power supplies, flatbeds and sheet-feeding scanners, too.
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Joined: 10 Mar 2011, 19:56
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Location: Tennessee River watershed

Math, Measurements, Ratios

Post by curious » 24 Mar 2011, 12:35

I'm starting this thread as a place to collect math, measurements, and ratios that we identify as unknown, and list them when we know them. Maybe this will consolidate to the wiki eventually ( http://diybookscanner.org/wiki/index.ph ... y:Hardware )
daniel_reetz wrote:To make a camera recommendation, can you tell us what size books you'll be scanning? There's a direct relationship between the size of the pages and the target DPI of your scans. (source http://diybookscanner.org/forum/viewtop ... =901#p9443 )
Translate megapixels to pixels per inch, needs to be above 300 ppi, and translate that to "page dimensions this can scan for A) human readable text, B) machine readable OCR-able, C) well-recorded images." (source = me).
vynx wrote:Is someone have calculation if the object is paper with size A4 then the camera is min. x Mega Pixel, or if the paper A3 then the camera is min. y Mega Pixel? (source http://www.diybookscanner.org/forum/vie ... 9627#p9627 )
Some of this information is on the wiki: http://diybookscanner.org/wiki/index.ph ... Resolution
daniel_reetz wrote:The exact distance of the lights above the platen is something that's easy to figure out after you've built the base - just lift up the floods until they don't appear in the camera image anymore. I'm sorry to say I've never done the math on that. If anyone else has info, I'd be glad to hear it. You could also take measurements from the New Standard, it works as described. (source http://www.diybookscanner.org/forum/vie ... =805#p7858 )
benjamin wrote:Initial setup and calibration is really the sticking point, ideally what I want is a prompt that just asks you to input book dimensions, then tells you how high to place the camera and sets zoom levels automatically. In a distant future this could even be done automatically- place the book or a calibration card on the platen, start the program, camera zooms out, takes a preview image and based on that system decides the vertical required to center it and the zoom level to crop out the borders. (source http://www.diybookscanner.org/forum/vie ... t=20#p4081 )

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