Re: Minimum Camera for Book Scanning
Posted: 26 Jul 2011, 21:26
no apology needed really.daniel_reetz wrote:caelum, sorry to be absent from this discussion.
Good, glad to know my camera is 'capable' now to see if "I' am. LOL My brain was really lost in your pixel explanation. Whew.. But re-reading I almost 'get it' but not very functionally.Yes, 8MP is "enough" for smaller sized books. There is a little basic math that can help you with this. Let's say a good scan starts at 200 pixels per inch of paper (note that this is a low number). If your books are ten inches long, you need 2000 pixels to capture that page. (note that, to simplify, I am only dealing with one dimension (the long edge) of the paper)
igh ? well, sort of. I do realize the picture/scan will include a outside margin around the book. Most books I'm doing are 5 x 8 pages or so, but there may be an 8 x 10 one I may need to.Now the truth is that you never get to use all 2000 pixels. Only 60 to 70 percent of those pixels actually have the book page in them because of lens distortion, book misalignment, book shape not matching the image dimensions (like a long thin book) whatever. So you need some margin for error. Let's say your camera had 3000 pixels, now you can comfortably capture 10" documents at just above 200ish pixels per inch of paper.
The settings on my camera are almost correct except for the tungsten I can't find without the manual. I built the cardboard version today, two cardboard wedges. And have a glass and book ready to go. I even have a tripod we found years ago as a throw away. Do you use a flash with the picture/scans ? Or with all the lighting no flash at all ?
Well, if someone could actually help me with anything I would be most grateful! Not that I'm not willing to try work this out, but my brain can only take it so far. LOL where are these mechanical triggers in Norway ? Anyway to find him and would it be easy enough for me to use as well ?As far as the CHDK things, OMG, their wiki is AWFUL. Sorry about that. When you get to the trigger-stage, we can help you install CHDK or it's sister project SDM. And there are USB triggers you can buy from a guy in Norway? Or somewhere. I've never bought one but people here have been very happy with them.
With that said, do you ever build simple scanners and ship to us less-fortunate-technical-deficient people. ?Thanks for your patience with the masses of technical information spread all over this site. Believe me, I know that there are holes in the instructions and that it is quite hard to find things sometimes. But we are slowly getting to a point where that won't be a problem any longer, and I am working on that.