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#1
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infra-red and mirrors
Hello,
I am designing an aircraft for a university project. The specification states the aircraft needs camera capable of recording IR video, PAL format, 10cm rsolution. I am considering using a kind of periscope in stead of those big spherical "gimball" jobs. If I used a series of mirrors and the camera was embedded deep within the aircraft, would the infra-red camera still work? Any help would be greatly appreciated. Best Regards, Adam |
#2
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infra-red and mirrors
"Adam Chapman" writes:
If I used a series of mirrors and the camera was embedded deep within the aircraft, would the infra-red camera still work? If you mean near-IR, then probably yes. Simplest experiment is get hold of a camcorder with nightshot and point it at your bathroom mirror on IR and see what happens. |
#3
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infra-red and mirrors
The aircraft need to watch the ground from a height of 300m. I do not
quite understant what you mean by near-IR |
#4
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infra-red and mirrors
"Adam Chapman" writes:
The aircraft need to watch the ground from a height of 300m. I do not quite understant what you mean by near-IR IR refers to a range of frequencies. The higher IR frequencies are near the frequencies of visible light and are called Near IR. The lower frequencies are further away and are called far IR, thermal IR, etc. The ones in the middle are called medium IR. Imaging with thermal IR has traditionally required chilled sensors though I gather there's ways around that these days. Near IR imaging is not much different than ordinary photography. |
#5
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infra-red and mirrors
Thanks for the help. I really appreciate it.
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#6
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infra-red and mirrors
Adam Chapman wrote: Thanks for the help. I really appreciate it. Get a copy of "The Infrared Handbook" http://www.amazon.com/Infrared-Handb.../dp/096035901X You are going to need it. Scott |
#7
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infra-red and mirrors
Adam Chapman wrote: Hello, I am designing an aircraft for a university project. The specification states the aircraft needs camera capable of recording IR video, PAL format, 10cm rsolution. I am considering using a kind of periscope in stead of those big spherical "gimball" jobs. If I used a series of mirrors and the camera was embedded deep within the aircraft, would the infra-red camera still work? Any help would be greatly appreciated. Best Regards, Adam Yes, but you may need to watch the material used for the mirrors. For near IR normal mirrors should work. For thermal IR, gold is better, and the mirrors MUST be first surface ones. Glass and aluminum oxide protective overcoats will strongly absorb thermal IR. Aluminized mirrors, even first surface ones, will oxidize and eventually dim in the thermal IR so they are not really recommended. The amount of gold needed to coat a metal or glass substrate isn't really that much so is not prohibitively expensive. |
#8
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infra-red and mirrors
Don Stauffer in Minnesota wrote:
Adam Chapman wrote: Hello, I am designing an aircraft for a university project. The specification states the aircraft needs camera capable of recording IR video, PAL format, 10cm rsolution. I am considering using a kind of periscope in stead of those big spherical "gimball" jobs. If I used a series of mirrors and the camera was embedded deep within the aircraft, would the infra-red camera still work? Any help would be greatly appreciated. Best Regards, Adam Yes, but you may need to watch the material used for the mirrors. For near IR normal mirrors should work. For thermal IR, gold is better, and the mirrors MUST be first surface ones. Glass and aluminum oxide protective overcoats will strongly absorb thermal IR. Aluminized mirrors, even first surface ones, will oxidize and eventually dim in the thermal IR so they are not really recommended. The amount of gold needed to coat a metal or glass substrate isn't really that much so is not prohibitively expensive. I use aluminum coated first surface mirrors, standard ones off the shelf, uncooled in spectroscopy from 0.2 to 150 microns, that covers UV to far infrared. Uncooled mirrors are used in the thermal IR all the time, in the lab, on aircraft, on telescopes, and on spacecraft. Roger |
#9
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infra-red and mirrors
Thanks everyone, I was hoping i could coat the mirror in gold anyway because it will reduce the chance of being detected by radar |
#10
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infra-red and mirrors
The main reason I suggested the mirror periscope idea is because ny
aircraft needs to have a very low radar cross-section. A spherical gimbal would have the same radar cross section when the radar is looking at the aircraft from all directions, where as a simple flat plate mirror pokking out of the bottom would only have a significant radar signature over a very short range of directions. Any new ideas would be appreciated |
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