Assuming that the pictures were taken at the same magnification, were not
enlarged on processing into prints, and scanned at the same resolution, they
should be all at the same scale. However, a small variance is to be
expected due to analogue to digital conversion, in particular how the edges
are dithered.
Your best bet is to simply acquire the images digitally from the start.
A good 'benchmark' might be to have an object of known dimension in the
corner of each image to compare to.
- Justin Walker
University of Maryland
-----Original Message-----
From: ImageJ Interest Group [mailto:
[hidden email]] On Behalf Of Hector
Merchan
Sent: February 4, 2009 6:08 PM
To:
[hidden email]
Subject: [IMAGEJ] Pixel by mm equivalence in multiple pictures
Hello all,
People say there's no such thing as a stupid question. I don't know if I
agree with that completely, but I'll use it to my advantage. I'm new to the
analysis of images and pretty new to ImageJ, so, a lot of technicalities are
still beyond my grasp. But I'm getting there (I hope). One of those
technicalities is whether the number of pixels per mm is equal in all
images, provided that the images were taken under the same condition. To
make things clear, I have pictures of specimens that were scanned in the
same scanner, with the same size standard and under the same resolution. We
I use the "Set scale" I realized that the measurements are usually between
93-95 pixels/mm, and wondered if they should be the same to all images. If
not, I wonder if there's a way to standardize that.
Thanks for your help.
Alejandro Merchan
--
Hector Alejandro Merchan
Ph.D. Student
North Carolina State University
Department of Genetics
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