What is the Geometry of Endoscopic Vision?

[scott kirkpatrick]

Does anyone know what the world looks like from the tiny camera that sees out of an endoscope? Is it a fisheye view or rectilinear or something unique? What sort of depth of field? And how different is in vivo pathology from in vitro (looking at slices in dishes)?

Just curious, since this seems to be an extremely common medical tool now.

scott

[Asher Kelman]

Scott,

Fro Gastroenterology and bronchosocopy, where everything is round, it seems like the lens is fisheye.

Although the ENT (ear nose and throat does not show distortions for the vocal cords, so it seems rectilinear.

For laporoscopic surgery where complex decisions are needed to preform skilled cutting, stitching, cauterizing, stapling and so forth, I can imagine that it would be anything but rectilinear.

I haven't looked up any of the 'scopes but a search of laperoscopy instruments would give you the details.

Interesting. Are you going to do surgery now? Hmmm!

Asher

[Dawid Loubser]

Nah, he wants to build an adaptor to put one of those lenses on his SLR :-)
What would the crop factor be?

[Asher Kelman]

I don't know, but now perhaps I might look for an adapter.

The DOF is pretty good. I am not sure what the focus range would be but i guess it would be about 15 cm at the most. There's no control over aperture.

Asher

[Duke Beattie]

You may find this interesting--
http://www.innovision-optics.com/lenses.shtml
This one is just odd........
http://www.endoscopepartsplus.com/index.html

[Michael Fontana]

Some years ago, I had tested - for architecture modell shots - endoscope's on a SLR, and yes; some are fisheye's, others are rectalinear. Correct me if I' m wrong, but they went from 140 - 180 degrees

But the result didn't sadiesfied me. Instead of endoscope, I went for the Perspektar, a special lens, built on purpose for architecture modell shots, in a little serie only, during the 80ties. If you go on my website, klick on services, and chose the 2nd icon, you'll see how this looks like, it' s the right picture.

It provides a much better (bigger image circle), and less distorted picture than any endoscope, I found at that time.

[Carsten Wolff]

A little bit off-topic: But I also know of a researcher who used a long endoscope, connected to a camera to survey reef crevasses underwater. My kind of guy! And I think the BBC Nat. History unit used them as well. You can get different optics for them thats all I know.

[Asher Kelman]

Carsten,

I still have a rigid Storz endoscope. I'll have to see if I can dig it up! field just covers the vocal cords and a little more! I wonder what the resolution is. I doubt there are enough glass fibers to match my macro lenses!

Asher

[fahim mohammed]

I shall ask my gastro consultant. A super gastro-entrologist, trained in Germay. He would not even apply

a local coating of anesthetic as he manipulated his Siemens and Olympus endoscopes inside me.

Alters, he maintained, a patient's ( me ) behavior and responses which he insisted gave him information in

addition to the pretty pictures of my pyloric ulcer and other lacerations. Benign, I am happy to report.

A doctor's doctor. He seems to have mellowed with age and uses mild muscle relaxants nowadays. But I

am glad he does not do colonoscopies.