infrared under water

I received my Master's in Remote Sensing and the infrared spectrum barely penetrates water.
Infrared doesn't travel any distance through water. Now blue-green will travel a lot farther through water.
 

HI: Obviously nfunk knows what he is talking about. My suggestion is to remember what IR is and it's freq. range. Then remember that H2O is used to quench it, i.e. put out the fire, cool the engine etc.,

Of course much would be depend upon what you intend to use it for? Specialized close up photography ?

Don Jose de La Mancha
 

nfunk said:
I received my Master's in Remote Sensing and the infrared spectrum barely penetrates water.
Infrared doesn't travel any distance through water. Now blue-green will travel a lot farther through water.

Hi nfun,

i am intrigued, by your comment on having a masters in remote sensing, in what context or scope does that degree encompass ?. as that could cover soo many different types of targets (metals,military,people,planets,etc.), equipment or methods, scale or to what degree (nano-freq-thermal, UHF,VHF, PI, spectrum) ?,

there is a reason that i'm asking... but... i won't bother going into details just yet. but given the site we are on i'm assuming that you had your eye's set on metal or treasure sensing capabilities :wink:

i also noted that you have a plane as your avatar, could that be your working platform ?.
 

Lobsterman,

My Master's is in Geography, but the vast majority of my work have been remote sensing of water, specifically HABS (hazardous algae blooms). When I say remote sensing it encompasses multispectral and hyperspectral satellite imagery (MODIS, LANDSAT, SeaWIFS, ASTER, etc) low altitude hyperspectral imagery (AVIRIS flown on the U2, TR2 aircraft)with in situ water quality analysis. The spectrum includes very long IR (thermal) through the ultraviolet and includes microwave (radar).

In this context infrared spectrum penetrates only centimeters while the blue green spectrum can penetrate many meters.

As for the plane, yes it is a Piper Cherokee 180 which is mine.
 

Goday !

Check in with Randy Wayne White. In his last novel, his character utilized this device for night diving and low light work. It does exist, only at great expense. Just don't light it up if you are diving in a IR critter hungry environment.

Joe
 

nfunk said:
Lobsterman,

My Master's is in Geography, but the vast majority of my work have been remote sensing of water, specifically HABS (hazardous algae blooms). When I say remote sensing it encompasses multispectral and hyperspectral satellite imagery (MODIS, LANDSAT, SeaWIFS, ASTER, etc) low altitude hyperspectral imagery (AVIRIS flown on the U2, TR2 aircraft)with in situ water quality analysis. The spectrum includes very long IR (thermal) through the ultraviolet and includes microwave (radar).

In this context infrared spectrum penetrates only centimeters while the blue green spectrum can penetrate many meters.

As for the plane, yes it is a Piper Cherokee 180 which is mine.

So i just came back across this old thread and i got to thinking... Could large gold deposits actually be found from the air, or even from space, by using modern remote sensing technology ??.
Obviously wrecks have been found using google earth, but i am talking about natural gold ore deposits. Is there something like groung penetrating radar or sonar that can be done from the air ??. Given the density of gold, and the advancements of the past 10-20 years, i wouldn't be suprised if the technology to find it exists.
 

Good morning fisheye. For some reason I couldn't find any reference to IR usage, just a green light and a light amplifier, which is in line with what lobster man posted, and my limited knowledge .

Incidentally, I enjoyed your data in your post, fascinating, and has given me new ideas which are applicable to my projects.

Lobster man, yes it does exist, and I have used it.

Don Jose de La Mancha
 

IR night vision devices have been around for a long time.I think it was invented in 1936.I have a working 1942 IR night vision snooper scope that was used on a M-1 garand.Spec ops guys used them.ordinary navy,army and jar heads didnt even know they existed back then.I showed my uncle this scope,he told me if he had one he could have shot down more jap planes and sunk more battleships flying at night.He was a ACE hellcat pilot on the lexington.Satans kittens was the name of his squadron.VF19
 

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Yes,

contact Randy Wayne White of Sanibel Island Doc Ford's fame. Randy is available to through the restaraunt.

ep wright
 

Someone must be confused about what is IR and what is not. There was no mention of IR in the underwater article.
 

Why use IR lighting ? IR can be used when you want to see something but you do not want to be seen . When diving in dark water and you want to see a subject you have to aim a light on it . Only Blue and green light is the right lighting for this purpose ( it travels the greatest distance ubder water ) . So why use an IR light with an IR receiver ? Cornelius ( ps , my ROV has green and blue lights on it )
 

Yes, IR light cannot be seen by people. You need an IR emitter, and a reciever such as a night vision, or a camera that processes IR. I have 2 Sea View UW video cameras that have IR emitting LEDS, you cannot see the light, it does not make murky water clear, you can only see as far as you can with a facemask, and you need a special reciever to see it. If diving, you need visible white light. I am sure you could use blue or green lights, but the color is very distorted, and white makes visible sense. Plus all the underwater lights have white light.
 

Real de Tayopa Tropical Tramp said:
Good morning fisheye. For some reason I couldn't find any reference to IR usage, just a green light and a light amplifier, which is in line with what lobster man posted, and my limited knowledge .

Incidentally, I enjoyed your data in your post, fascinating, and has given me new ideas which are applicable to my projects.

Lobster man, yes it does exist, and I have used it.

Don Jose de La Mancha

Hi Real,
I am sorry for pulling up an old topic but what is the technology used for such long range sensing called ??, is it done by using planes with some type of off the shelf sonar or something for imaging high density areas ??, or does it use satelite and photo IR type of info sensing ??? sort of like this nasa imaging program... http://visibleearth.nasa.gov/view_rec.php?id=1887
I sure would like to get or use some of the government's geological info or imaging from over Alaska !!!.
 

Stevemc . White light does not travel under water as far as the colors green and blue . So a combination of these two colors gives you the best result . Cornelius
 

I'm going to try modified digital camera, have one being shipped to me right now. From what I understand, a blocking device to filter out IR and UV installed inside digital cameras, by manufacturer because the sensor without is full spectrum. I've looked at some photos taken by modified digital cameras & camcorders, I can't see a difference from other images by IR photography film or devices.

I don't know about usefulness of underwater IR/UV photography, full spectrum digital IR you would think could combine visible, UV, and IR for the low light levels underwater. In some tests on fishing lures underwater, colors affected the most by UV light remained visible down deeper. Anyway, I'm going to work with it some on land, see what can be accomplished, different light levels.
 

This is all new to me, you read conflicting comments on this subject in some threads. I'll have to do my own tests.
 

Red Desert,

Digital cameras MAY have a filter before the sensor to block IR. This would be uncommon these days. A very easy way to know is just get any remote control device that uses IR...and press the buttons while looking at the screen on the camera. Most will show the IR signal 'light'
Now what you have to do, is buy an IR filter for the lens. This will block the non-IR freq from reaching the sensor. (you will have to set the camera to record the image RAW or Black and White)
The resulting image will be of just the IR freq response...

When underwater, it would be best to match the frequency of your torch to an IR range. You should have a very powerful source, that will have IR bands in the frequency, that way, your image will record the reflectivity properly.

good luck!

(what you are seeing is basically the modified cameras have had the filter removed, and then a filter is added to the lens...it is far easier to avoid the expense, and the result is the same)
 

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