Any home built thermal imager cameras?

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Roach
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Any home built thermal imager cameras?

Post by Roach » Sat Sep 06, 2008 8:07 pm

I see that many hand held thermal imagers exist. They are used in fire departments and construction..

Finding leaks, or hotspots..

I would like to make one from existing technology, anyone have any experience in this??

kalasek
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Post by kalasek » Sun Sep 07, 2008 1:58 pm

hi

I have had some success using old ccd cameras without their i/r filters and using two polorized filters as a adjustable light filter you must have to make sure the filters are not i/r coated.

bob

Roach
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Post by Roach » Mon Sep 08, 2008 10:24 am

kalasek wrote:hi

I have had some success using old ccd cameras without their i/r filters and using two polorized filters as a adjustable light filter you must have to make sure the filters are not i/r coated.

bob
Thanks, it's a start. Any particular brand? I am going to start scrounging, or I will look for some disco units at the chains.

regards,
R.

rshayes
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Post by rshayes » Tue Sep 09, 2008 11:49 am

Silicon photosensitive devices, such as those used in digital cameras, are sensitive to light with wavelengths shorter than .9 micron (900 nanometers or 9000 angstroms). Objects close to room temperature emit very little radiation in this region. This is considered "near infrared".

For longer wavelengths, atmospheric absorbtion, is high until a "window" of low absorbtion occurs between 3 and 5 microns. This is considered the "mid infrared" region. A usable amount of thermal radiation is emitted by room temperature objects in this region. Image detectors for this region are usually some type of bolometer array (for moderate sensitivity) or detectors made from materials such as Indium Antimonide or Lead salts, which are photosensitive in this region but usually require cooling substantially below room temperature for good operation.

The next "window" is between 8 and 14 microns. Most of the radiation from room temperature objects is emitted in this region, called the "far infrared". This makes it a good choice for "thermal" imaging. For moderate sensitivity, bolometer arrays can be used. High sensitivity requires special materials, such as Mercury Cadmium Telluride, cooled to temperatures in the neighborhood of 77 kelvin (boiling liquid nitrogen).

Th imaging systems sold to law enforcement are usually based on bolometer arrays. These are usually based on mechanical structures based on deposition, photolithography, and chemical etching processes. The fabrication processes are similar to those used to make integrated circuits, so it is unlikely that they can be duplicated at the hobby level. At best, these arrays cost hundreds of dollars to the manufacturer. They have mostly been developed over the past 15 years, and are probably rare to nonexistant on the surplus market.

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jwax
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Post by jwax » Tue Sep 09, 2008 1:56 pm

Fairly unuseable is the POS I built years ago, based on an "Image Convertor" tube, circa 1945. I think it was "Gen 1" of infrared imaging equipment. Maybe "Gen 1/2".
I bought a Gen2 (?) from a sporting goods store. Good for finding your keychain in a dark room, but very short range.
Military devices are up around Gen4 or Gen5.
What are you going to use it for?

Roach
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Post by Roach » Tue Sep 09, 2008 1:58 pm

[quote="rshayes"]Silicon photosensitive devices,

Good job!! Thanks for the info. I would think we have some folks who have access to these neat devices, but as you said, it may be too soon.

The hand held units I saw were in a contractors catalog. They can help find a water leak in a roof, or look for drafts, and poorly designed construction. Or, they can point out good construction too (glass half full approach).

My need is for the above primarily, but I have assisted in animal rescue. Having access to this technology would be helpful.

Regards, and thanks.

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kheston
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Post by kheston » Tue Sep 09, 2008 8:14 pm

Roach,

Sounds pretty neat!

What was the brand and model you saw in the contractor's catalog. Was the cost less than $10k? :)
Kurt - SF Bay

Roach
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Post by Roach » Sun Sep 21, 2008 4:31 pm

kheston wrote:Roach,

Sound pretty neat!

What was the brand and model you saw in the contractor's catalog. Was the cost less than $10k? :)
Yes, the price is still out of my need/league at about $4 to $6k.
Look under FLIR

www.flir.com/ contractor stuff

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