Posted by
Mario-2 on
URL: http://confocal-microscopy-list.275.s1.nabble.com/Re-Ana-alarming-amount-of-image-manipulation-tp592857p1313148.html
Re: An alarming amount of image manipulation - time
to fig
(I apologize if people are getting this message twice. My problem
is that my last couple of posts have not been acknowledged or sent
back to me as part of the list. Thanks for your patience)
Oh Criminy,
I have tried to stay out of this. I now feel compelled to
comment:
1. the human visual dynamic range under normal viewing conditions
is much less that 8-bits (256 levels); its more like 6-bits (64 levels
or worse). Thus, it is inevitable that microscopy images confocal or
W.F. will require manipulation in intensity and contrast (and gamma
correction) in order to generate prints or downloadable images that
demonstrate the experimenters claims. It is rediculous that
anyone should retract a paper because of minor intensity or contrast
changes. It would be nice to know what procedures were carried out on
an important data set and could be described in a few sentences.
Further, I agree with advocates that original raw image data be made
available by the journal and/or researchers upon request. In fact,
uncompressed raw image files should be provided to the reviewers of a
paper. Might save a lot time. As for Catherine Verfaillie and
colleagues, without knowing the details, it seems like a black eye on
common sense on the part of U of Minn. sorry don't mean to offend but
consider item 2.
2.As for journals, different publishers use different settings
for printing images. In my opinion, they must bear some of the
responsibility for getting the images to print as the authors wish,
but much of the time they tell the authors merely to enhance contrast
because the journal prints tend to lose contrast and images appear
washed out. I have experienced that even enhancing contrast to an
absurd degree resulting in an image that is grossly inappropriate on
my computer monitor, can still lead to inadequate contrast when
printed in a journal! On the other hand, my experience with the
journal Science was quite positive in that their Photoshop layout
person worked with me to get the right print quality. I think it would
be beneficial if all microscopy journals and others employing images
did the same.
3. When it comes to creating fraudulent images free of
manipulation artifacts, it is actually very time consuming and
difficult, and I don't know why anyone would even bother. (Well
actually, I do, but besides being immoral and unethical, it is not
worth the trouble. You will be found out and your career will go down
the drain). Anyway, before anybody gets paranoid, I know this from
doing digital reconstructions of damaged historically important
photographs (e.g., 90-100+ year old photogravures, metalochromes,
platinum prints, etc). I try to create replicas of images that are as
close to the originals as possible. Depending on the degree of damage
or artifacts in an original print, it could take several weeks to be
successful with a single 11"x17" original using the full
image processing arsenal including Fourier analysis, building notch
filters, etc.
Early in this thread it was mentioned that a histogram analysis
can often reveal selective image tampering. I also think that this is
a useful tool especially when it is applied with noise analysis on
subsets of an image. Areas that have been manipulated by sharpening,
blurring, selective intensity changes, and other types of local
manipulation will create tell tale features that might not be visible
to the eye but can be revealed by disproportionate statistical
inconsistencies within the image as a whole. Systematic errors due to
improperly adjusted PMT voltages or problems with amplifier gain
dependent noise in a CCD camera can also be detected.
Mario
The issue of the recent request by the
University of Minnesota to have Catherine Verfaillie retract her
publication is worse than tragic: it has all the elements of a
Puritanical witch-hunt, and all for the charge of changing the
brightness level of three images. Let me be quick to say
that Morayma Reyes, the graduate student who was picked out for the
"offense," changed brightness levels to conform the image
for publication, exactly what a printer at the printing press would do
(but somehow comes clean), and exactly what I advised her to
do.
Believe me, no list of ethical rules by
the Microscopy Society could EVER be written to have changed this
outcome--which was clearly an investigation for political
reasons--except one rule: no post-processing period (which is done
anyway at the press: are they accountable, too?).
It is especially disheartening because Dr. Reyes is among the best
researchers I have worked with. I cannot forget the day when she
called me into a room long after regular working hours and asked me to
look through the microscope. I saw a beating heart before this
had ever been done with the use of stem cells. I turned to her
and commented, "This is too large for a rat heart and too small
for a rabbit. What is it?" She smiled triumphantly
and said, "We made it on a scaffold."
I agree wholeheartedly with Johan: fight back. Especially for
this so-called violation on research that has since been corroborated
by other labs.
Jerry
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