-------- Original Message -------- Subject: Re: idea about image acquisition Date: Sat, 17 Sep 2011 06:17:50 -0400 From: Carmelo Fruciano <[email protected]> To: [email protected] morphmet <[email protected]> ha scritto:
-------- Original Message -------- Subject: idea about image acquisition Date: Thu, 15 Sep 2011 18:20:00 -0400 From: David Thulman <[email protected]> To: [email protected] I have used a decidedly low-tech method for image acquisition by using a flat-bed scanner. I've used this for bifacial archaeological artifacts (but they have a lenticular cross-section that looks like a fish). The scanner I've used is an Epson 4180 Prefection (cost was less than $100), but most scanners these days with a CCD should work fine. The scanner has a depth of field of at least 1 cm, and probably more than 2 cm. The error was less than .01 mm (tested with a digital caliper). The images were scanned at 600 dpi, which eliminated the need for a scale for the analysis I did. I used the images for a traditional morphometric analysis (length, width, ratios, etc.), but recently uploaded them into tpsDIG2 and have started reanalyzing with GM. Laying a fish on the scanner platen may get messy, but its an alternative that should produce precise images at low cost and fuss for the right kind of specimens.
There is a paper on the use of this techique on fish by Herler et al. (A simple technique for digital imaging of live and preserved small fish specimens. Cybium 2007, 31(1):39-44). If I'm not mistaken, there has been some other previous work using scanners on other organisms (I cannot remember it now, though). However, for large fish specimens there might be some problem (size of the plate, thick body and the like) and I would check also for "distorsions" along certain directions (Herler et al, again, talk about some of these problems). All the best Carmelo -- Carmelo Fruciano Dipartimento di Biologia University of Catania Tel. +39 095 7306023 Cell. +39 349 5822831 e-mail [email protected] http://www.fruciano.it/research/ ---------------------------------------------------------------- Universita' di Catania - A.P.Se.Ma. Servizio di Posta Elettronica
