Diff for "EMAN1/FAQ/e2scannereval_results"

Differences between revisions 1 and 9 (spanning 8 versions)

Q) In this (scanned from film) image, what are the weird looking Fourier tiles indicative of? Also, should this question be in the EMAN2 section? I think that that region labelled B is normal but that A and C are strange, maybe film warping? I am using a Nikon super coolscan 8000 ED there is no mechanism for holding the film flat.

attachment:e2scanner_image.png

A) Very nice example of warped film in the scanner. You are seeing the MTF of the scanner lens when out of focus. This data may still be usable with sufficient averaging (ie - if you average by ~2, you will push the first ring in the MTF to almost Nyquist). This is exactly the sort of effect e2scannereval.py is designed to detect.

EMAN1/FAQ/e2scannereval_results (last edited 2009-04-22 14:42:55 by SteveLudtke)

-  ⇤ ← Revision 1 as of 2007-02-21 22:30:03 → 
  Size: 178
  Editor: bdh-granite
  Comment:
+   ← Revision 9 as of 2007-06-07 16:08:47 → ⇥
  Size: 704
  Editor: DavidWoolford
  Comment:
-Deletions are marked like this.
+Additions are marked like this.
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-I uploaded an image and it's called neg195_scannereval_lowres.png
+Q) In this (scanned from film) image, what are the weird looking Fourier tiles indicative of? Also, should this question be in the EMAN2 section? I think that that region labelled B is normal but that A and C are strange, maybe film warping? I am using a Nikon super coolscan 8000 ED there is no mechanism for holding the film flat.
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-I would like to put it here and ask the question
+attachment:e2scanner_image.png
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-What are the weird looking Fourier tiles indicative of?
+A) Very nice example of warped film in the scanner. You are seeing the MTF of the scanner lens when out of focus. This data may still be usable with sufficient averaging (ie - if you average by ~2, you will push the first ring in the MTF to almost Nyquist). This is exactly the sort of effect e2scannereval.py is designed to detect.