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

Original ~600pg/hr, very portable scanner now achieving ~900pg-1100pg/hr

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.
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Mohib
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Re: Original ~600pg/hr, very portable scanner now achieving ~900pg-1100pg/hr

Post by Mohib » 28 Mar 2017, 20:07

In the mean time I decided to test out my original idea (a steel cable and turnbuckle) to hold the vertical assembly together (without the U-bolt and hose clamp), before I thought about the nylon strap and buckle.

It is very solid and I prefer it over the nylon strap, although that works very well and easier and faster to use, so I'll use that when travelling.
Scanner 900 - Vertical post cable clamp 2a.jpg
Scanner 900 - Vertical post cable clamp 2a.jpg (369.54 KiB) Viewed 834 times
Scanner 900 - Vertical post cable clamp 8a.jpg
Scanner 900 - Vertical post cable clamp 8a.jpg (391.33 KiB) Viewed 834 times
Scanner 900 - Vertical post cable clamp 7a.jpg
Scanner 900 - Vertical post cable clamp 7a.jpg (418.46 KiB) Viewed 834 times


dtic
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Re: Original ~600pg/hr, very portable scanner now achieving ~900pg-1100pg/hr

Post by dtic » 29 Mar 2017, 03:36

Mohib wrote:
28 Mar 2017, 19:20
Yes and no. It all depends on what one is willing to compromise and the scanning objectives.
Right, and also dependent on what more is at hand at the location.
Mohib wrote:
28 Mar 2017, 19:20
1) Vibration ... ... 3) Size - Height and reach

The flexible arm could grip another table, or a stack of books on another table or something secured to a wall/ceiling.
Mohib wrote:
28 Mar 2017, 19:20
2) Levelling

Don't move the phone or arm. Every 30-40 pages slide more and more sheets from a spiral notebook under the book, or between two rubbery mats under the book.
Mohib wrote:
28 Mar 2017, 19:20
5) Lighting
I wonder if there are battery powered LED lights with sufficient brightness and low weight to be clamped to the same arm as the phone. Or another such arm.

IKEAs suction cup wall mounted LED lamp also look quite portable but is only 40 lumen, http://www.ikea.com/us/en/catalog/products/60312292/

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Mohib
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Re: Original ~600pg/hr, very portable scanner now achieving ~900pg-1100pg/hr

Post by Mohib » 29 Mar 2017, 12:13

dtic wrote:
29 Mar 2017, 03:36
The flexible arm could grip another table, or a stack of books on another table or something secured to a wall/ceiling.
That starts to complex matters and makes the scanner dependent on what the environment has to available to make it functional instead of being self-contained and requiring only the edge of a table (which is almost never an issue, especially at a library for example - where the tables are usually in the middle of the room).

Furthermore, the moment you have to touch the camera to adjust anything the vibration will set in again.

The reviews on Amazon about these flexible mounts is mixed when it comes to vibration so they will require testing, and all may not be the same too. I think the idea is good for certain situations if vibration is not an issue.
dtic wrote:
29 Mar 2017, 03:36
Don't move the phone or arm. Every 30-40 pages slide more and more sheets from a spiral notebook under the book, or between two rubbery mats under the book.
That will be much slower and more inconvenient than a quick, precise turn of a knob on the macro focus rail, which also lets you see the page image while making the adjustment so you can get the change just right without experimenting and fiddling. And, once again, moving the book means it will have to be re-positioned back in the field of view. I think image scale is just a compromise one will have to accept with these flexible mounts, assuming vibration is not an issue.
dtic wrote:
29 Mar 2017, 03:36
I wonder if there are battery powered LED lights with sufficient brightness and low weight to be clamped to the same arm as the phone. Or another such arm.
The LED outdoor lamp I use is 900 lumen and is sufficient from 18" away, but really two are needed if even lighting is needed. However, for text only books processed by Scan Tailor, almost any decently bright lighting is good enough.

I toyed with the idea of attaching a bike lamp to the platen handle, but the problem is it is too close to the platen so sets up a hot-spot reflection in the image. The lighting needs to be further away to avoid that. Even mine hanging at the top of the vertical post is a bit close for larger books and the horizontal support should be a 3 inches longer to eliminate hot-spot reflections in the platen. But there are many bike lamps with over 1,000 lumen and have clamps that can help with attaching them somewhere.

Another option are those ultra-bright LED flashlights advertised on TV (if they are re-chargable, else I can see them getting expensive). The Bell & Howell Tac Light is 600 lumen and not re-chargable. Others on Amazon are 800-1000 Lumen and re-chargable, but they'll need some kind of adaptor to hold them.

But these battery lamps (bike or flashlight) can be quite expensive, and more so if you have to also get separate rechargeable batteries, but they are an option.

dtic
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Re: Original ~600pg/hr, very portable scanner now achieving ~900pg-1100pg/hr

Post by dtic » 29 Mar 2017, 17:13

Yeah there are pluses and minuses I suppose. I agree your design is more self-contained and already very compact, so good work.
the moment you have to touch the camera to adjust anything the vibration will set in again.
Yep a wireless trigger would be a must if a flexible arm is used.
that will be much slower and more inconvenient than a quick, precise turn of a knob on the macro focus rail
Slower yes but maybe only a few seconds extra per adjustment? Haven't tried it though.

Soon smartphone cameras probably have enough resolution and image quality to skip moving the camera down or the book up during a session. Instead we'd just zoom out until there is some extra space around the pages and afterwards software crop all images down to whole book pages and then resize all those pages down to the same pixel dimensions as of the last page.

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Mohib
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Re: Original ~600pg/hr, very portable scanner now achieving ~900pg-1100pg/hr

Post by Mohib » 29 Mar 2017, 17:37

dtic wrote:
29 Mar 2017, 17:13
I agree your design is more self-contained and already very compact, so good work.
Thanks!
dtic wrote:
29 Mar 2017, 17:13
Slower yes but maybe only a few seconds extra per adjustment? Haven't tried it though.
Based on my experience with just shifting the book while scanning (the pressure from the platen slowly pushes it left), a complete removal of the book to fiddle underneath it would be quite a break from scanning as you'd have to:

- move the book and rubber mat,
- place the filler stack of papers,
- place the book and rubber mat back,
- centre the book in the view finder,
- hope it's the right amount of filler stack and not have to repeat.

I think you'd be looking at a lost +/-1 min and the disruption of your rythm, and the hassle of papers. Also I'm not sure if a stack under the book will affect stability of using the platen as the book will not be sitting flat on the table and as the platen makes the book itself slide, it may end up falling off the stack of papers below causing more problems and delays.
dtic wrote:
29 Mar 2017, 17:13
Soon smartphone cameras probably have enough resolution and image quality to skip moving the camera down or the book up during a session. Instead we'd just zoom out until there is some extra space around the pages and afterwards software crop all images down to whole book pages and then resize all those pages down to the same pixel dimensions as of the last page.
Actually there's enough resolution even with my old iPhone 4s as this is only a very small movement (thickness of the book, from top to bottom). See the side-by-side example from the start and end of a book I posted here (taken with a camera with similar resolution to the iPhone 4s): viewtopic.php?f=14&t=3007#p17556

But yes, the real solution requires a software improvement. I made some suggestions and on how I think it could be done in Scan Tailor here: viewtopic.php?f=14&t=3007&p=17550#p17550

And in much more detail on their GitHub here: https://github.com/scantailor/scantailor/issues/89

But I'm sure those with more experience can work out better software methods.

dtic
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Re: Original ~600pg/hr, very portable scanner now achieving ~900pg-1100pg/hr

Post by dtic » 29 Mar 2017, 18:46

If I understand the issue correctly a small script could fix that prior to ScanTailor.

The script inputs would be the imagefolder path and the image resize percentage X needed to make the text characters on the last page to have the same pixelheight as characters on the first page.

The script would then loop over the input folder images and incrementally enlarge each image more until the last image is enlarged X percent.

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Mohib
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Re: Original ~600pg/hr, very portable scanner now achieving ~900pg-1100pg/hr

Post by Mohib » 29 Mar 2017, 22:44

Well character size may not be a reliable standard as font sizes may be different on early and late pages (due to title pages etc).

However, from what your'e describing it seems that all that would be needed is a calibration sheet (say a 1" checker board) that can be easily de-skewed and analysed. So you'd scan it first (placing it on top of the first page of the book) and again last, (placing it on top of the last page after scanning the book) and the size difference of the squares (by number of pixels) between the first and last image would give the image scale change which can then be applied across all pages proportionately.

It might not even need a special calibration pattern, but just a sheet with some bold pattern -- that Scan Tailor can consistently and accurately auto-content select -- that is just scanned as both the first and last page. Then, if there was an option in step 5 (so after the auto-content selection of step 4) to say first and last images are calibration pages, the scale factor can be determined -- by comparing the number of pixels (width or height) the auto-content selection found for the two calibration images -- and applied as part of the margin application process (since there is already scaling being done when they are applied).

dtic
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Re: Original ~600pg/hr, very portable scanner now achieving ~900pg-1100pg/hr

Post by dtic » 30 Mar 2017, 07:44

The chance of this niche feature being added to Scan Tailor is very small I think. Your best bet is an external script.

To get you started check out this quick proof of concept using Autohotkey and GraphicsMagick. Note: only tested very briefly, but seems to work as expected. I haven't examined how the resize affects image quality. It overwrites all jpg files in the folder you specify so backup the images first if you want to keep the originals. The script operates on the jpg files in file name order.

Code: Select all

#singleinstance, force

;RESIZE_INCREMENTAL
;autohotkey script
;----------------
;SETTINGS
;add full path to graphicsmagick gm.exe
gm = 
;example: C:\Program Files\GraphicsMagick-1.3.25-Q8\gm.exe

;add path to folder with jpg images to process
imgfolder = 
;example: C:\folder\some subfolder\

;measure the height (in pixels) of 6 lines of text
;on one early and one late image in the folder
firstimg =
lastimg =
;example firstimg = 438
;example lastimg = 420
;----------------

if !FileExist(gm) or !FileExist(imgfolder)
 exitapp
;get resize percent to equalize lastimg to firstimg pixelheight
lastresize := ( firstimg / lastimg ) * 100
Loop, files, %imgfolder%\*.jpg
 count++

Loop, files, %imgfolder%\*.jpg
{
if (a_index == 1)
 continue
tooltip %a_index%/%count% --- %thisresize% -- %A_LoopFileName%
thisresize := (lastresize - 100) * (a_index / count) + 100
RunWait "%gm%" convert "%A_LoopFileFullPath%" -resize %thisresize%`% "%A_LoopFileFullPath%",,hide
}
tooltip DONE
sleep 2000
exitapp

dpc
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Re: Original ~600pg/hr, very portable scanner now achieving ~900pg-1100pg/hr

Post by dpc » 30 Mar 2017, 12:35

Please don't take offense to my suggestion, but if your goal is to produce a single page scanner that can be easily setup in remote locations such as a library, I'd encourage you to build something like this.

It's dirt simple to build and operate, less expensive, far more portable, and doesn't have the varying image size problems that your design has.

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