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

Book Liberator beta

Built a scanner? Started to build a scanner? Record your progress here. Doesn't need to be a whole scanner - triggers and other parts are fine. Commercial scanners are fine too.
vitorio
Posts: 138
Joined: 30 Oct 2010, 23:56
Number of books owned: 0
Location: Austin, Texas, USA
Contact:

Re: Book Liberator beta

Post by vitorio » 12 Nov 2014, 00:56

Turns out there was latent adhesive gunk on either the acrylic or the cradle, because when I went to dust off the platen, there was residue on one of the cradle/acrylic sides. Very annoying, and it's not coming off great.

Anyway.

I moved the table and the Book Liberator directly underneath that overhead light, which is about 30" directly above it. In this configuration, it's far enough above the platen that it's not catching the light bulbs directly, and I could see it being usable for casual scanning, especially if you're just looking to capture text. More diffuse light higher up would be even better, but for rigorous work, you're going to want a blackout tent or pitch-black room, and an overhead lamp 36"+ directly above the BL (48"+ tall total off the table), similar to the old Sola Technical build.

Here's what that looks like:
bl1020test01.jpg
bl1020test01.jpg (136.47 KiB) Viewed 3818 times
(7136×5360 JPEG, 11.3MB)

As noted before, in the 4:3 38MP orientation, the cradle is 11.5" wide, ~5000 pixels,~430dpi, and you can see the entire cradle.

Here are some photos of test charts at 4:3 38MP. I used a full-size printout of this ISO 12233 chart, an 8.5×11 crop of it, and a full-size four-up of of the Bob Atkins chart that qv_ used. I did no other calibration at all; everything is automatic out of the Lumia Camera app. (You need to use the Lumia Camera app to get the full-resolution photos, not the stock Camera app.)
bl1020test02.jpg
bl1020test02.jpg (161.69 KiB) Viewed 3818 times
(7136×5360 JPEG, 12MB)
bl1020test03.jpg
bl1020test03.jpg (156.91 KiB) Viewed 3818 times
(7136×5360 JPEG, 11.5MB)
bl1020test04.jpg
bl1020test04.jpg (160.17 KiB) Viewed 3818 times
(7136×5360 JPEG, 12MB)

Here are the cradle and the full ISO 12233 chart at 16:9 34MP. Again, I did no calibration at all; everything is automatic out of the Lumia Camera app. The cradle width is ~5100px or ~440dpi, but you only get 9 or so inches of height. I'm not sure it's worth it for the extra hundred pixels or so.
bl1020test05.jpg
bl1020test05.jpg (105.04 KiB) Viewed 3818 times
(7712×4352 JPEG, 10MB)
bl1020test06.jpg
bl1020test06.jpg (130.71 KiB) Viewed 3818 times
(7712×4352 JPEG, 10.2MB)

Now, on the other hand, if you position the camera in portrait, in 4:3 38MP, you can just barely fit the entire cradle width into view at ~5300 pixels wide, just eeking out ~460dpi. (I did this by hand, not with the tripod adapter.)
bl1020test07.jpg
(5360×7136 JPEG, 12MB)

At 16:9 34MP, you can get perhaps 9" of the cradle width in view, ~2600px for 5.5", or ~470dpi.
bl1020test08.jpg
(4352×7712 JPEG, 10.9MB)

A portrait effort at either ratio is probably worth it if your book is the size of the cradle or smaller.

I know I don't have enough blackout cloth left to make a new tower, so that'll be an effort for another day.

kfogel
Posts: 4
Joined: 10 Oct 2014, 17:48
Number of books owned: 0
Country: USA

Re: Book Liberator beta

Post by kfogel » 28 Jan 2015, 03:10

Thank you for the measurements, and the photos! That helps. We're gathering data from other users too, but this is by far the most detailed feedback (as you might not be surprised to hear).

qv_
Posts: 39
Joined: 01 Jul 2014, 17:33
E-book readers owned: iRiver
Number of books owned: 1000
Country: Sweden
Location: Sweden, Södermanland

Re: Book Liberator beta

Post by qv_ » 07 Feb 2015, 17:50

That ISO chart can only show 2000 lines (pixel) in height if it´s the real stuff.
Home made is not that good.

This sensor is 5360 pixel (7712x 5260, 8,8mm x 6,6mm)

This means in practis that this ISO chart only work for a 6 mpix sensor if the sensor is a 8,8 x 6,6 (2933x2000)
so this chart can "only" show resolution from 0 - 2000 lines if all the lines are clear (or 1000 pair of lines).

In this case the chart on the picture is not using the "hole sensor height" so it can show more but you have to scale it again.

I did not look on the download pictures if all lines were clear so I can not tell if this 41 mpix sensor did make a 6mpix resolution but hopefully it did.

The amount of pixel you have in the (JPG)file is not equal to the real dpi on the picture in that file.
this sensor will create 5260 pixel in the file but that do not say that you can se 2630 per of lines (5260/2).

And that is the goal with scanning. To see all line pair on the picture.
/Jan

Post Reply