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

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by dpc
31 Aug 2011, 15:27
Forum: Scanners and Build Threads
Topic: qbit's book scanner project
Replies: 8
Views: 5805

Re: qbit's book scanner project

If you zoom-in all the way and then move the camera position back, does the barrel distortion go away?
by dpc
19 Aug 2011, 14:35
Forum: Scanners and Build Threads
Topic: Fix Keystoning via hardware adjustments
Replies: 37
Views: 20075

Re: Fix Keystoning via hardware adjustments

Has there been a scanner build using a fixed cradle and allowed the platen to shift horizontally as well as move vertically? If you did this and then attached the cameras to arms attached to the platen (instead of to the base), you would get the page in the same location within the captured image ac...
by dpc
17 Aug 2011, 16:26
Forum: Scanners and Build Threads
Topic: Fix Keystoning via hardware adjustments
Replies: 37
Views: 20075

Re: Fix Keystoning via hardware adjustments

The Olympus camera that I'm using at the moment has the 'x' and grid overlays as an option out of the box. I haven't used CHDK so I don't know if it offers the same feature. BTW, in a V-shaped cradle, the center of the page will move during the course of a book scanning by the width of the spine (bo...
by dpc
21 Jul 2011, 16:06
Forum: Scanners and Build Threads
Topic: Fix Keystoning via hardware adjustments
Replies: 37
Views: 20075

Re: Fix Keystoning via hardware adjustments

@Eppi, That's probably the best way to ensure that things remain aligned. I suppose you'll have to be concerned with the camera casting a shadow depending on where your lights are positioned, but other than that it should work OK. My camera has an onscreen display where it will draw an 'X' across th...
by dpc
20 Jul 2011, 12:54
Forum: Scanners and Build Threads
Topic: Fix Keystoning via hardware adjustments
Replies: 37
Views: 20075

Re: Fix Keystoning via hardware adjustments

Now we established that c was 12 The degrees of the three corners are AB = 90° BC = 30° AC = 60° What will be the correct formula for calculating line a line b Length of 'a' = cos(AC) * c Length of 'b' = sin(AC) * c So with 'c' = 12... a = 0.5 * 12 = 6 b = 0.86025 * 12 = 10.4 Whether your trig f...
by dpc
20 Jul 2011, 01:38
Forum: Scanners and Build Threads
Topic: Fix Keystoning via hardware adjustments
Replies: 37
Views: 20075

Re: Fix Keystoning via hardware adjustments

To convert degrees to radians you multiply the number of degrees times the value PI/180: radians = degrees * (PI / 180) degrees = radians * (180 / PI) 30 = radians * (180/1.61803399) This is wrong, as you should be using the value of PI (3.1415927) instead of 1.61803399. 30 = radians * (180 / 3.1415...
by dpc
19 Jul 2011, 16:59
Forum: Scanners and Build Threads
Topic: Fix Keystoning via hardware adjustments
Replies: 37
Views: 20075

Re: Fix Keystoning via hardware adjustments

Use the Excel function RADIANS to convert a value in degrees to radians.


sine of BC (30 deg) should be 0.5.

cosine of BC should be 0.8660254
by dpc
16 Jul 2011, 19:21
Forum: Scanners and Build Threads
Topic: Fix Keystoning via hardware adjustments
Replies: 37
Views: 20075

Re: Fix Keystoning via hardware adjustments

If you have a right triangle and know the length of one side and one of the other angles, you can find the length of the other sides using sine and cosine functions. Given a right triangle with sides a, b, and c, with c being the hypotenuse, and BC being the angle formed by sides b and c: a = sin(BC...
by dpc
15 Jul 2011, 00:33
Forum: Scanners and Build Threads
Topic: Fix Keystoning via hardware adjustments
Replies: 37
Views: 20075

Re: Fix Keystoning via hardware adjustments

If you know the length (L) of the green line segment between the red and yellow camera direction vectors in the diagram below, then the vertical distance between those two lines (i.e. the amount you'll need to translate the camera) is simply L / cos(cradle_angle / 2). (The cradle_angle of the standa...
by dpc
30 Jun 2011, 17:55
Forum: Scanners and Build Threads
Topic: Aluminium build from Australia
Replies: 2
Views: 3649

Re: Aluminium build from Australia

Looks nice and clean. Will have any problems with reflections off all those shiny parts?