Author Topic: High quality, high resolution digital optical USB microscope  (Read 1417 times)

Probeman

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    • John Donovan
Re: High quality, high resolution digital optical USB microscope
« Reply #15 on: June 05, 2018, 04:02:56 pm »
As posted earlier, with the lightbox we got this image of our reflective sample holder:



See the blurred/blackish area near the center of the sample holder?  That is from the black underside of the document camera as seen through the hole in the top of the light box and reflected in the sample holder surface.

So we then added a blank white mailing label to the underside of the camera (with a small hole for the camera to see through!) and now we get this:



We're happy now!
The only stupid question is the one not asked!

Ben Buse

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Re: High quality, high resolution digital optical USB microscope
« Reply #16 on: October 29, 2018, 07:10:12 am »
Hi John,

I guess you use thin sections, how does the camera work for them?

Have you tried using a light box under the thin sections, or a light shining through them - similar to that used for photograph negatives.

Thanks

Ben

Probeman

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    • John Donovan
Re: High quality, high resolution digital optical USB microscope
« Reply #17 on: October 29, 2018, 12:55:42 pm »
Hi John,

I guess you use thin sections, how does the camera work for them?

Have you tried using a light box under the thin sections, or a light shining through them - similar to that used for photograph negatives.

Thanks

Ben

Hi Ben,
For actual glass thin sections we always utilize our Nikon Coolscan slider scanner as seen here:

https://www.amazon.com/Nikon-CoolScan-LS-50-Film-Scanner/dp/B0001DYTVW

Ours is 15 years old, but still is 4000 DPI (~6 um pixels) and really designed for 35 mm photographic slides though it came with a holder for biological glass slides. We paid $2000 for it, but now they are around $1000.  We ended up making a holder for petrographic glass slides and it is perfect for geological thin sections.  We even made a holder with some polarizing sheets of plastic for obtaining a crossed polarized image.

That said one can find ultra high resolution pathology slide scanners that go to 20K or 30K DPI!  A bit more expensive though:

https://www.bioimager.com/uscopemxii.html

They claim 0.5 um optical resolution!

Yes, we've played around with using the document scanner and light box and it generally works but for highly reflective samples it can be problematic due to glare issues.  Here is a grain mount that we used recently and it worked by having the sample on a piece of white paper to reflect light through the grains. 



Of course the issue then is that even grains that are not intersected at the surface still show up.
The only stupid question is the one not asked!