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

Issue that starts at step 5 - Margins

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Rhea27

Issue that starts at step 5 - Margins

Post by Rhea27 » 17 Mar 2011, 11:13

I just got my 2nd camera (not using SDM yet because I don't have the switch and cables yet). Everything was fine in Scan Tailor until I got to "Margins", where every other page turned into a tiny little image...obviously the pages from the 2nd camera. I tried to attach an image on this post, but am not sure I know how to do that. Any advise on what might be causing this issue?
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Tulon
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Re: Issue that starts at step 5 - Margins

Post by Tulon » 17 Mar 2011, 11:29

Obviously your camera is putting wrong DPI values into the pictures. The DPIs going from cameras are *always* wrong, as cameras don't know the real size of objects they photograph. When you create a project, tick the "Fix DPIs even if they look normal" option. On the "Fix DPI" dialog you may need to work on the "All Pages" tab rather than on "Need fixing", as some of them apparently look normal to Scan Tailor.
Scan Tailor experimental doesn't output 96 DPI images. It's just what your software shows when DPI information is missing. Usually what you get is input DPI times the resolution enhancement factor.

Rhea27

Re: Issue that starts at step 5 - Margins

Post by Rhea27 » 17 Mar 2011, 12:11

Thanks Tulon. I have been unclear on how to estimate DPI on the types of things I'm scanning. I built my DIY scanner to scan old photos albums, scrapbooks, etc...so I am not scanning books with lines of text which can be measured for DPI. How is DPI measured for the types of things I'm scanning?

Tulon
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Re: Issue that starts at step 5 - Margins

Post by Tulon » 17 Mar 2011, 15:37

You can scan a book page just to measure the DPI. It's going to persist until you change the zoom level of your cameras. Even better, scan a ruler, then measure how many pixels correspond to one inch. That would be your DPI.
Scan Tailor experimental doesn't output 96 DPI images. It's just what your software shows when DPI information is missing. Usually what you get is input DPI times the resolution enhancement factor.

Rhea27

Re: Issue that starts at step 5 - Margins

Post by Rhea27 » 19 Mar 2011, 13:21

Thank you. I think I've figured out how to determine DPI using Gimp. Which brings me to a new question...When I try to enter a value lower than 150 in Scan Tailor, the text is red and the APPLY and OK buttons are dimmed and unavailable. Is 150 the minimum that can be entered?

Tulon
Posts: 687
Joined: 03 Oct 2009, 06:13
Number of books owned: 0
Location: London, UK
Contact:

Re: Issue that starts at step 5 - Margins

Post by Tulon » 19 Mar 2011, 13:41

Rhea27 wrote:Thank you. I think I've figured out how to determine DPI using Gimp. Which brings me to a new question...When I try to enter a value lower than 150 in Scan Tailor, the text is red and the APPLY and OK buttons are dimmed and unavailable. Is 150 the minimum that can be entered?
The idea is that a DPI lower than 150 is likely to be the DPI of your screen rather than your scan, probably inserted by some image editor / converter / etc. If that's not the case and your DPI is really less than that, it's considered to be of too low quality to get anything good out of it.
I suggest you post an example shot here - then I'll tell you for sure where the problem is and what can be done about it.
Scan Tailor experimental doesn't output 96 DPI images. It's just what your software shows when DPI information is missing. Usually what you get is input DPI times the resolution enhancement factor.

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