Cardboard box training rig - first book done!

[600dpi]

I completed my first full scan of a book with my carboard box training rig...

The Canon SX20is is running CHKD and I've put together a remote using a momentary pushbutton (Maplins,UK), a 3 AA battery holder and clip (maplins, UK) and all spliced together with a USB cable and some odd bits of wire. The switch is housed in an old film container.



I got a nice big box, sliced and spliced and reinforced with glassfibre tape. I used some Scotch 3M spray to stick some black card to the right hand side. I also made a "belt" of card to tuck the left hand side pages under (the test was a paper back, but no dice with a hardback!).



The tripod is mounted using a scrap piece of wood (with two holes drilled for the front two legs) and clamped to the bench (not shown here).

The glass "platen" is from a picture frame and has a "handle" made from 1/16 inch ply, some square softwood and a wedge of balsa underneath, all held together with 5 minute Epoxy and then sprayed black. I added an A4 black card to the end with scotch "Diamond" tape to mask the left hand pages.



I noticed a lot of the fancy designs have the two book cradle halfs moveable relative to each other for different sized books, and on some of the cardboard box designs, they're split along the "hinge" line. What I've done, is to find a range of "V" (and other) shaped inserts of various sizes (mostly balsa, some carbon fibre rods and off cuts of soft wood mouldings) here's an example:



These are now to be officially referred to as "V-serts".... Any ways, for the first runthrough with a book (160 page paperback) I used a small 1/4inch balsa triangle. The view from the camera (no zoom applied) is:



I got through the book in several sessions on Saturday evening. There were a few problems with each component: camera, USB remote, glass platen, the book cradle and it took way too long!

Getting the USB remote to work with CHDK and the Canon SX20is was a long-winded affair, and the main problem being the WIKI page that shows it all working with one 3volt CR2032 battery. Just couldn't get it to fire, then found some references to trigger voltages being >3.4volts, added an AA beneath the CR2032 and then it worked (and which is why it's using 3 AAs)! In use the camera tended to fire at times when I wasn't even holding the remote (during page changes), not at all sure why this was happening.

The black card at the end of the glass plate seemed a good idea at the time, but it didn't help hold the pages down and after initial tests the 4 inch wide belt was added. I also used a blank page underneath the right-hand page being photographed. So all this meant that changing pages was way too slow and long winded. I also needed to tug this a bit to flaten off the LH pages.

The lighting was a big variable, started off in the garage with a single Halogen task lamp and natural light and ended up in the dark with two halogen task lamps and the fluorescent strip light on.

The "Homer" suite of software worked flawlessly and after processing the images in Scan Tailor my first book was done. Whoo hoo! There are a few (five or so) duff pages (the text looks 'bold'). There's a lot to sort out, but this was a great training and educational run. The top priority is now making a proper V-shaped platen and making the page turning much slicker and more reliable and quicker. So it was off out tonight to get some 15 x 10 inch glass etc etc...

[rob]

Good job! I wonder if there's a way to make a cardboard scanner that has the glass on the top and the camera on the bottom. The biggest problem with paperbacks and a cradle is that paperbacks need a lot of force to stay open, which you've discovered

[600dpi]

I wonder if there's a way to make a cardboard scanner that has the glass on the top and the camera on the bottom.

How about:
Use just one side of the slit box
Cut a window slightly smaller than the glass pane at the apex
attach the glass with diamond "clear" tape, reinforce with glass fibre tape to the "roof" make sure the top edge of the glass is at the apex.
Get one dinning room table that splits apart for an extension.
Place the lighting directly underneath on the floor.
Put the camera on a tripod underneath the table and opposite the pane
Paperback now sits on the the top
- well its a thought

The biggest problem with paperbacks and a cradle is that paperbacks need a lot of force to stay open, which you've discovered

I probably shouldn't have attached the wide belt at both ends, but left if free at the front (so that it didn't slow down changing pages and which was really tricky for the left hand pages (pulling them out)....

[daniel_reetz]

I love the handle idea! I always fingerprint up the glass when I show the cardboard box scanner to people.

[600dpi]

I love the handle idea! I always fingerprint up the glass when I show the cardboard box scanner to people.

Yeh, the handle worked well. I still managed to get some fingerprints on it though! I'm tempted tweak the handle further by adding some side supports and an opposite piece or fence to hold the left hand pages down (which was my main problem). This would probably speed things up greatly.

[600dpi]

I decided to continue tweaking this cardboard box training rig. I need to get the page turning process quicker, so decided to beef up my integrated glass platen and handle. So here's version two. I added triangular sides and an end 'fence'. There's some triangular balsa supports for reinforcement and to spread the load around corners. It's all held together with 5minute epoxy. A quick sand and several dusting coats of black and she's ready to go!

I haven't tried it in anger yet, but it does seem to do the business with paperbacks holding them flat and open with ease. I'm wondering whether to add the remote button to the handle next?

[600dpi]

Decided to improve the lighting, since I only seem to be able to get half decent photos at high ISO settings >=400
Decided to get some halogen spotlights and whilst there were some GE ones in B&Q they didn't have any Edison screw fitting sockets. But the found that Maplins do Edison to Bayonet adaptors. The bulbs looked awesome so I got one of each:



and



So found some 3-core flex in the garage and a socket and put it all together on a scrap piece of wood and a cable tie to hold the cable out of the way. I clamped it to a conveniently positioned shelf about 1m or more above the book cradle. I didn't want to get "Arceye" when turning this baby on, so shielded my eyes. Pushed in the plug and!!>>>>.??? A TOTAL ANTI CLIMAX!!!

There just wasn't as much light as I thought, I was kinda hoping for a quantum leap, it IS more, just not as much as I hoped.

So I've also learnt that "Thou shalt have two 'alogen bulb thingies'. Anyhow, I guess the proof of the pudding is in the eating and we'll see what some photos look like later today...

[600dpi]

I guess appearances are deceptive. In use the new light worked well. I was able to drop the ISO value from 400 down to 100 but settled on 200.

I had a problem with the "improved" platen design in that the top of the ply fence opposite the handle (see image above) was being recognised by Scan Tailor as the edge of the page. This was inspite of having already added a sheet of black card to the outside of the ply 'fence', so to solve this I added another to the inside.

I did quite a few trial runs playing about with various camera settings and I have to admit that I'm now really just learning how to use the camera properly. Pages with little text were a problem, but I found that you can move the AF box about. I tried using manual focus, but this didn't work out well, since the combination of distance and zoom seems to be right at some lower limit or threshold and I couldn't bring it properly into focus. In the end I settled for Tv mode and speeds around 1/50 - 1/100 with F stops around 5.6 to 8.0 range and auto focus. Finally saving all this to the Custom (C) settings. There's a lot of similarity between my Canon SX20IS and the more recent SX40HS and there's a set of good tutorials for this camera by FatDragon100 on Youtube that I've found very helpful.

I re-did the same book that I did last week (a paper back with <200 pages but with a reasonable sized font). This time it took 46 minutes to complete the two passes. But then more than twice as long to sort out the images and end up with a set ready to feed into the "Homer" suite of apps. The problems I encountered were:

1) Missing pages (the sequential image numbering shows I turned two). Reviewing the output and identifying these takes time. So less haste more speed!
2) Sorting out multiple copies.
3) The CHDK remote firing off randomly. I really don't know what's going on here. It seems to happen throughout the session, but got much worse towards the end of the session: after taking a planned picture, the camera was firing off randomly whilst I was changing pages (and not even holding the remote switch). It felt like it was taking photos WHEN I was changing pages (motion detection?)! So the first pass of checking the images was deleting all the thumbnails images with my hands in.

Because sorting out the images too so long, I now need to pay attention to this aspect of the process. It might be worthwhile writing a quick directory listing utility to get a formatted worksheet of the images in a directory, in order to speed up image review and reduce the time of this stage of the process.

But after feeding the final sorted files through Homer:

The PDF produced is a significant improvement on my first attempt last week. The pages are all of a uniform quality, crisper and clearer and with no "bold" or duff ones.

[600dpi]

Just spotted something that I really don't understand.

The first attempt last week resulted in a PDF that was just under 10Mb in size.
The second attempt yesterday produced a PDF of the same book that is only slightly over 3Mb in size (a 1/3 the size).
All images were taken at the same resolution (4000 x 3000 pixels and all around 2.7Mb in size) and I used the Homer suite/Scan Tailor for processing the images and making the PDF?

Is it : Cleaner images = smaller size PDF?

[daniel_reetz]

That's possible - a clean, binarized (pure black and white image) takes less bits to encode than a color or noisy image.