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Re: [ITRDBFOR] recommendation for scanner A3 ???


Chronological Thread 
  • From: Peter Groenendijk <peter.groenendijk AT wur.nl>
  • To: Daniel Patón <d.paton.d AT gmail.com>
  • Cc: itrdbfor AT itrdbfor.org
  • Subject: Re: [ITRDBFOR] recommendation for scanner A3 ???
  • Date: Fri, 15 Nov 2013 12:33:18 +0100

We've used the same scanner as Daniel Patón and scanned long cores and (sections of) discs up to 150cm long. It's a good scanner with a high resolution. It also has a focus option (maunal or automatic), which allows for scanning of not flat surfaces (e.g. discs).
For discs it was not possible to scan the entire length at once, so we scanned several 'pieces' and then stitched them together in Photoshop. Depending on the program used for measuring the rings (we used WinDendro), the stitches do not need to be perfectly overlapping. Often these programs have tools to cope with 'gaps' in the cores/discs (broken cores, cracked discs) and this function can be thus be used to bridge the stitch gap.
As a matter of fact, we often scanned samples over the width of the scanner (so not making use of the entire length of the scanner) as the scanning is then a lot faster. Scanning over the entire length of the scanner can take up to 30 minutes, but by turning the samples 90 degrees your scanning length is reduced to the width of your samples. Of course this results in shorter core segments scanned and more stitches. But my experience is that, with a bit of practice on Photoshop, it wins you considerable time.

Hope it helps,

Regards,

Peter Groenendijk

PhD candidate
Forest Ecology and Forest Management Group
Wageningen University - The Netherlands
Project:
http://tinyurl.com/bpxkfxw
+31 317486221





On Fri, Nov 15, 2013 at 10:01 AM, Daniel Patón <d.paton.d AT gmail.com> wrote:
On Fri, 15 Nov 2013 08:42:32 +0100
"Tobias Scharnweber" <tobias.scharnweber AT uni-greifswald.de> wrote:

> Dear all;
>
> For optical-scanning of long cores we are looking for an appropriate
> scanner-model (A3 format or larger). Ideally the margins of the scan surface
> should also be as plain as possible (our cores are up to 80 cm in length).
> All kind of experiences are welcome!
>
> Best regards
>
> Tobias

Hello,

I have an scanner Epson _expression_ 10000XL (used by FBI for detection of falsifications in documents) and give a very high resolution (2.400 x 4.800 dpi).

This model is very fast if you connect with an operating system that can manage the high quantity of memory that is required. I recommend you FreeBSD, the UNIX of Berkeley Software Distribution. This incredible operating system is the best in performance.

However, you can use an A4 flat scanner and scanning the cores in two or three sections. If you put a signal in the core you can measure until the signal. Probably this system is much better, because you can work to maximum resolution in files of less memory. I discover this after buy the scanner ;-).

Good luck

--
********************************************************
 Daniel Patón Domínguez
 Numerical Ecology. Ecology Unit
 Department of Plant Biology, Ecology and Earth Sciences
 Faculty of Sciences. University of Extremadura
 Avda. Elvas s/n 06071 Badajoz (Spain)
 http://unex.academia.edu/DanielPatonDominguez
 https://www.researchgate.net/profile/Daniel_Paton/
 http://sites.google.com/site/numericalecologyuex/home
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