How about some infrared images

[Tin Can]

Useful

[jdaivpmed]

Good Morning Nodda,

Great explanation! I would like to just add a couple thoughts.

The bands of infrared wavelengths that Nodda is describing are not the only wavelengths that IR energy is active, there is still energy occurring in the wavelengths between those bands. These bands are defined not because of the limitations of emission of IR energy, but because of limitations to its transmission through our atmosphere. In other words, these bands coincide with "windows" in the atmosphere which allow for the transmission of IR energy in those respective wavelengths. Outside these windows virtually all IR energy is blocked, mostly due to water vapor, carbon dioxide, and ozone. As such, we design our detectors to work within these specific windows (in most cases, either the MWIR or LWIR bands). If we were operating in a vacuum then there would be no need to break the IR spectrum into these bands as there would be nothing to interfere with transmission of the IR energy.

Detector deseign and resolution has progressed greatly in the last two decades and there are now a great variety of systems available in the MWIR and LWIR bands. Each band has advantages over the other and as such they tend to be selected for a specific application. I believe that most of the uncooled microbolometer based systems still operate in the MWIR band, but there are certainly LWIR units out there now too.

This is an interesting crossover subject for me because my company (Bison Aviation) specializes in servicing airborne infrared (thermal) camera systems, primarily FLIR (Forward Looking InfreRed) units. Most of our clients use these systems for spotting bad guys on the ground, but there are other applications, such as utility surveys, animal population monitoring, and fire mapping. The vast majority of the airborne systems we service utilize cryogenically cooled LWIR focal plane arrays, though there are a few MWIR systems out there. By utilizing a cooled detector these systems achieve much higher sensitivity and thermal resolution than their microbolometer based counterparts. Of course that resolution and sensitivity comes at the cost of added mechanical complexity and of course financial expense. Currently the cheapest airborne system on the market costs about four times the price Nodda mentioned!

Despite their expensive and technologically advanced nature, I have yet to see a FLIR system that offers even the most basic view camera movements. Pan and tilt (actually elevation and azimuth in the FLIR world) is about all you're going to get with these cameras. Maybe I should gather up some spare parts and build the first thermal imaging view camera! Ha ha

John IV

[Nodda Duma]

Great follow-up and you are spot-on, John.

One thought about IR windows..I've found a growing interest in the (normally unused) 2-3um band for mining applications. I'm not too familiar with the details, but from what I understand there's better differentiation of minerals of interest from the surrounding rock in those wavelengths. The imaging ranges are short enough (30 ft or less) that atmospheric absorption isn't an issue.

[StoneNYC]

Definitely an interesting discussion, you should start a thread about non-traditional spectrum imaging, this is fascinating! Thanks for sharing both of you and for correcting my error on "seeing like snakes" I'm not so good with abstract, low contrast, blurry imagery so shooting "like snake vision" wouldn't be my best work hah!

I'm sad I only have 42 sheets of 8x10 left before I have to stick with 4x5 IR. I wouldn't be SO bummed if Rollie made theirs in 8x10, alas the market just isn't there for them plus the special precautions and difficulty with such thin sheets.

Something is better than nothing!

[mat4226]

Afternoon Glow, Highbanks Metro Park, Columbus, OH



Tachihara 8x10 + Fujinon W 250mm f/6.7 w/ R72 filter
Efke IR820 in Pyrocat HD 2:2:100

[uphereinmytree]

efke IR 4x5

[uphereinmytree]

efke ir

[StoneNYC]

efke IR 4x5

efke ir

Were these shot without an IR filter?

[uphereinmytree]

Shot with a b+w 092 filter which lets in some of the regular spectrum and keeps the contrast down some

[mat4226]

Winding Trail, Highbanks Metro Park, Columbus, OH



Tachihara 8x10 + Fujinon W 250mm f/6.7 w/ R72 filter
Efke IR820 in Pyrocat HD 2:2:100