In case anyone is interested I have a
directory full of photomicrography here:
http://www.science-info.org/pages/edfwill/
The videos in 'AVI' and the high resolution
in 'AP' might be interesting. The AP images
were taken at the limit of resolution for
light microscopy with visible light. The
lines on this diatom are spaced at about 220
nanometres. The dots (shown in some pictures)
are only 180 nm apart. To achieve this level
of performance extreme care and the very best
illumination and optics are needed. Emphasis
is on the care and I should add experience as
well. The learning curve for this kind of
work is as steep as it gets. I should add
that a simple modified web camera was used
for these pictures.
The videos were also made with this modified
web camera and the resolution is perfectly
adequate for high magnification. It is the
lower mags for which a camera with loads of
megapixels is needed. The *ist D is fine down
to about about 40X total magnification, after
this more pixels would be needed. There are
tables on the Nikon site for this determination.
Don
Rob Studdert wrote:
On 17 Feb 2006 at 9:51, Don Williams wrote:
Hi Rob,
The stacking of images has been done for a
long time in laboratories using electron and
light microscopes. We did this in the late
70s on an HP2000 system in my Institute. I
was able to entice a virologist from Holland
(despite Apartheid) to visit for a few
months. His work was mainly optical
transforms. We then developed a suite of
image processing programs using Tony
Crowther's (MRC Cambridge) ideas as a start.
But it took 8 hours or more to do a FFT, mask
and reverse FFT on a 512 x 512 matrix. I can
do it in a minute or two. And that time is
taken making the mask. The actual processing
is over before one's finger leaves the Enter Key.
Amazing, what scientists could have achieved years ago with all todays idle CPU
cycles boggles the mind :-)
The colour fringes are not a problem unless
one is concerned with aesthetics. I think it
would be less work to fix the final image
rather than the individual frames. I'll look
into this. What do you use for the job? The
collector, the condenser, the objective and
the eyepiece all contribute to the problem
and a combination of optics to eliminate them
entirely would cost about £20 000 at a rough
guess. As it is the objective I used for this
lists at about £1200.
Panotools could be used to batch process a set of images prior to stacking and
I would guess that once the correction parameters are determined they will
apply to all images captured with the same objectives and mag:
http://photocreations.ca/radial_distortion/ (outline)
http://www.abolais.nl/ca-cor.htm (more detailed and most suitable method for
your purposes)
There are less thorough options using GUI tools such as PTlens but the results
would be near as good.
http://epaperpress.com/ptlens/
Cheers,
Rob Studdert
HURSTVILLE AUSTRALIA
Tel +61-2-9554-4110
UTC(GMT) +10 Hours
[EMAIL PROTECTED]
http://members.ozemail.com.au/~distudio/publications/
Pentax user since 1986, PDMLer since 1998
--
Dr E D F Williams
__________________________________
http://www.kolumbus.fi/mimosa/index.htm
http://personal.inet.fi/cool/don.williams
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Updated: Added Print Gallery - 16 11 2005
