qbit's book scanner project

[qbit]

Here is my almost finished DIY book scanner project.

Main Materials:
Wood, plywood, aluminum channel, pexiglass

Cameras:
Canon A480 with CHDK

Software:
Scan Tailor
PhotoBatch (may possibly use it)
JPEGbox
Photoshop CS5.1
Adobe Acrobat Pro X


All I need to do now is semi-permanently mount the cameras in the current position (drill holes and add fasteners then remove the clamps).

The base unit is designed to translate horizontally a few inches off center if required for larger books.
There is a SPDT switch used to switch the +5VDC to the cameras' USB ports.
The cameras are powered by adapters
There is some black antislip matting on the black top of the book holder and as well as in front of the height adjustment of the pexiglass (had some reflections off of the metal fastener)
The pexiglass has a section cut out of the side closest to the stand to allow for the pexiglass to not hit the book as the pexi pivots upwards
There are white lines in the black plywood for image center
Also used are spacers that fit under the book to allow for larger books to remain flat in place
The camera mounts are made such that the cameras do not have to be removed for removal of the SD cards


I am amazed at the quality of scans that are achievable by this unit.
Using some minor post processing for image quality, converting the final scans to .pdf via Acrobat Pro X makes almost a perfect scan.

Scan Tailor deskews great, but there is a touch of a barrel effect from the camera's optics and some other minor optical deviations that were completely cleared up when converted to .pdf via Acrobat (using ClearScan).

... the results speak for themselves (from a cookbook copyright 1942 - hopefully this does not conflict with any applicable laws - if it does please remove the attachment)
look at the page number (for some reason not OCR'd) and you can see the individual pixels, whereas the main text employs ClearScan is nice and smooth.

Thanks guys for all the ideas - hope this helps others with building their own DIY book scanner

qb

STEPS IN CANNING FRUIT AND TOMATOES.pdf

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[dr1]

Looks great! Very clean and simple.

How did you join the plexiglass together? And how thick is it?

[qbit]

update: unit complete

Mounting screws now instead of clamps
I still might use the clamps on an odd-ball sized book, but for most applications the screws are perfect

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sample calibration picture

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and a camera view - I use lots of grids to make sure the image is square as possible
i would like to eventually output the camera video to a monitor for real time monitoring of the image quality

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with one of my most recent books, I did a DPI calculation at the different zoom levels
0 zoom = 250dpi
1 zoom = 285dpi
2 zoom = 350dpi
3 zoom = 430dpi

but only smaller books can be done at 2x; 3x is not usable
my scans are at 1x zoom

That is it!

[qbit]

Looks great! Very clean and simple.

How did you join the plexiglass together? And how thick is it?

the main plates are 3mm thick and the end pieces are 5mm thick

there is an acrylic glue that i used (bought from the place where i bought the pexi; they sold me a small amount of the can as that i didn't need much)
the solvent glue was incredibly thin and had to use a syringe to administer the solvent

you place the plates together and let slide just a small amount of this solvent into the 'to be' joined edges
the solvent will flow in quite easily so don't use too much (make sure your cut edges are nice and flat - this makes a better weld)

let set and it makes a really hard weld

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[daniel_reetz]

Really beautiful work Qbit - thanks for sharing, and for the specifics. I'm heartened to see your high-to-very-high DPI and other technical info here.

[dr1]

Hi qbit, thanks for responding before. I've drawn up some plans modelled after your build and put them on the forum. I'd appreciate your input.

I couldn't figure out how your base moved - does the whole thing move relative to the light stand, or do the two halves of the cradle move somehow? Also, how far away are your cameras from the page?

[qbit]

Responded to your thread.

The whole base moves relative to the light stand.
The black book supports are 17 3/4" away from the front of the camera (lens fully retracted)

I think that it would be neat if the two halves could move separately, but my work around was to keep them fixed and use the spacers that I made (simpler and works just as well)

edit: for those interested in my project, read the post in the other thread as it provides some very specific modifications to successfully address some issues

[dpc]

If you zoom-in all the way and then move the camera position back, does the barrel distortion go away?

[qbit]

I thought about using a longer distance between the image source and the camera and tried the max zoom.
There were lighting issues (resulting in poor image quality) apparent, plus keeping an exact center would of been a bit more difficult (not impossible).

I found that at the zoom I used I achieved a balance between lighting, barrel distortion, and the ability to lift the pexiglass without hitting the cameras. If you look at my sample pdf, using Adobe Acrobat cleared up the remaining barrel distortion.
I will be looking into using a photoshop plugin to remove any barrel distortion prior to production into a pdf in case Acrobat fails to process correctly when it processes a more complex image.