http://imagej.273.s1.nabble.com/Optical-artefact-removal-tp3702076p3702082.html
photography are bad things for microscope microphotography). Well,
exposure with the speed. After this you will need also to play with
Le 18 juil. 06 à 15:22, Vasseur Monique a écrit :
> Hi
>
> Hi Jacqueline,
>
> Looking at your image, I think you have sort of a light leek
> somewhere in your optical . Do you have 2 light sources on your
> microscope? Or one port that is not light proof? I had that
> problem with a fluorescence Nikon upright microscope when we where
> acquiring images in transmitted light and that the mercury lamp was
> on (at that time we where missing an empty filter cube in the
> filter turret) but we could avoid the diffraction effect by closing
> the manual fluorescence shutter on the microscope.
>
> But for your actual images, I guess you could easily do a shading
> correction by:
>
> 1- getting a background image (a spot on your slide but out of the
> specimen area) with the same parameters of exposure time and
> binning than your specimen image
> 2- than you divide your specimen image by the background image to
> get your shading corrected image.
>
> Monique Vasseur
> Microscopie et imagerie
> Département de biochimie
> Université de Montréal
> tél. (514) 343-6111 poste 5148
> -----Message d'origine-----
> De : ImageJ Interest Group [mailto:
[hidden email]] De la part
> de Jacqui Ross
> Envoyé : 18 juillet 2006 02:41
> À :
[hidden email]
> Objet : Optical artefact removal
>
> Dear All,
>
>
>
> I have had an enquiry from someone from another Department who has an
> artefact affecting their imaging which looks like a diffraction effect
> (e.g. Newton rings) when doing transmitted light microscopy.
>
>
>
> I had a look at their microscope and camera system and even when
> Koehler
> illumination is set up properly, you still get this effect. The
> microscope is a rather old Nikon inverted microscope with a Coolpix
> attached. The objectives, (phase contrast), are not infinity corrected
> and I'm assuming that there is also a problem with the tube length for
> the camera. The rings are there irrespective whether specimens are on
> glass or in plastic dishes. I don't think much can be done optically
> (correct me if I'm wrong) but I wondered if some image processing
> could
> help.
>
>
>
> My ImageJ question is this:
>
>
>
> Is it possible to use some kind of image processing (e.g. image
> subtraction) to remove this artifact? I have tried a few things out
> (e.g. Image calculator, rolling ball) without much success so far.
>
>
>
> I have posted 2 images at the following address:
>
http://www.health.auckland.ac.nz/biru/exptal_images/index.html
> There are
> also links to larger images although the original images are even
> larger
> than these.
>
>
>
> Please note that I do know that these images are appalling! I asked
> one
> of the students to send me one image with tissue (glass slide) and one
> without at the same focal plane and this is what I got! I don't think
> they set up the microscope very well. However, you can see the rings
> clearly on both images so I hope they will inspire someone to
> suggest a
> solution.
>
>
>
> I would be very pleased to hear of any potential solutions.
>
>
>
> Cheers,
>
>
>
> Jacqui.
>
>
>
> Jacqueline Ross
> Biomedical Imaging Research Unit
> School of Medical Sciences
> Faculty of Medical & Health Sciences
> The University of Auckland
> Private Bag 92019
> Auckland, NEW ZEALAND
>
> Tel: 64 9 373 7599 Ext 87438
> Fax: 64 9 373 7484
>
>
http://www.health.auckland.ac.nz/biru/> <
http://www.health.auckland.ac.nz/biru/>
>
>
>
Laboratoire des Rickettsies du Pr. RAOULT
Fac. de Medecine de la Timone