See in total darkness at low cost?

[cgng]

Hi all.

I am thinking of a way to allow a low lux camera to see at a range of 1 km in total darkness and at low cost.

Any body can help.

Thanks
:o

[bearcreek]

Well it depends on your definition of "total darkness" and "low cost". If $10,000 is low cost you can buy an infrared thermal imaging camera like law enforcement agencies use, though it might be a bit heavy for your aircraft. If there are a few stars in the sky or a partial moonlight then a .0001 lux ccd camera with a high gain lens and possibly a several second exposure time such as the astronomy hackers do with their telescope cameras would be nice, though I am not sure about all the electronic specifications on doing it (or if it would be compatible with a normal video receiver). Also an image intensifier like night vision or illumination from a million candlepower search light depending on what your application is.

[cgng]

Thanks for the reply.

"low cost" means to use low lux camera and not FLIR.

I have try using a 0.002lux ccd to see in the night with full moonlight but can hardly see anything at long range (say 1km).

Thinking of using laser (laser can travel 1km, i think) to illuminate the scene and use the 0.002lux ccd to see.

Any idea this will work? any article that was written on this?
Sorry for asking so many question. I am really a newbie in this area.

Thanks a lot

[bearcreek]

That laser idea is intriguing. The thing is that it seems that a laser would only get light into a small area per unit time, so maybe if you hooked the camera up to something like a telescope that could slowly scan the entire area it might work, but then it would be much slower than video frame speed.

I have seen some ordinary ccd cameras that were slowed down to like 20 second exposures and the light sensitivity was unbelievable, but for a moving vehicle we need fast frame rates.

There is a thermal infrared FLIR helmet camera on ebay today for $2750 buy-it-now http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7595787055

It would at least be neat to see what the neighbors are doing behind their house walls!

[JettPilot]

The laser thing will not work, you will not be able to light up a large area with a couple mw of light. You dont get something for nothing, a laser will go a long ways and make a dot, it will just not light up a large area.

If you want to see at night, just get a night vision scope with video output...

[bearcreek]

How wide a field of view do you need at 1 km? 100mw Infrared laser diodes with collimating lenses are inexpensive and can usually be refocused to diverge the beam slightly like a flashlight. It wouldn't be bright, but possibly similar to moonlight for a narrow FOV.

[Tuner]

Ahh wounderful great question.
You need to state a price range though. Because I know of some great CCD's that are not IR sensitive and cost 10+ thousand to buld the camrea/
Also Weight Is HUGE Factor.

Use High dynamic Range Imaging. You will need to Digitize the video and this step is crucial the better converter you use the better your low light.
Once you digitize the signal for One frame of video you take multiple exposures and then combine all these frames so you can see the details in the bright areas and dark areas. This will not help though if you can not see what you are looking for in the dark areas with you exposure turned all the way up Iris Wide open and your frame rate reduces as much as possible.

Also I would love to know what CCD you are using as I am very well versed in camera electronics and .002lux CCD seems like a marketing scam either that or it has a photo multiplier OR it is awful with well lit areas and great with dark this is possible I guess!???

Asking for an inexpensive VIDEO Rate CCD to perform well in low LUX environment is like asking for Cheap Telescope that can see planets in other solar systems.


Id love to see the actual CCD specs. Or part number brand...

That said when dealing with optics you learn the joys of the law of squares.
Basiclly the intesity of light eminating for a point source is exponential.

A Laser would work if scanned in a conical pattern fast enough but would not show depth very well as would any light source that is close to your camera due to the shadows angle being parrallel to the lightsorce.
Also Lasers are very low power light sources the only reason they seem bright is because all that power is focused in a small beam spread that beam out and its nothin. But If you scan it that could be another story and it is a technique done by military equiptment. "I was involved in designing a laser tracking system myself"

The reason I asked about weight Is you can Use either a Large parabolic Mirror or Large Camera Optics to intensify the image.
In Fact i am willing to bet you can easily double to quadruple your scenes intensity with the proper optics but once agian what are you willing to spend and how much can it weigh.

Also Cooling a CCD can reduce its self noise in the dark areas.

In the end YOU ARE SCREWED.

Not to mention Moonlight is very bright relative to just starlight and what do you do when you are not near a city and its completely overcast.

Lots and Lots of research goes into this topic not to discourage as I think you can work something out that suites you needs
You are just dealing with fundumental limits of physics at these levels where the thermal vibration of electrons starts to be your main noise source.

A photo Multiplied CCD is your best choice in my opinion.
But I have no idea why you would not want an IR based CCD setup it has so many more advantages and flexibility.

PM me if you have any specific question or want to rap about this in detal.

Scott

[Tophinater]

Maybe what your after isnt nesseccarily a camera. Have you thought about using Ladar? There are many military robots under R&D right now that are having great success with it. Im not sure about the cost or elecontrics of it tho.

[Tuner]

LADAR is great but WOW is it heavy. Maybe a hobby version can be lightweight.

Another term to use is 3D Laser scanning or interferometry.

A wounderful technique.

Once again I still think finding a PhotoMultiplied carmera(Starlight night vision NON I.R.) on eBay.

[patrickegan]

Not only doe’s the laser beam idea not sound plausible but flying around with the laser beam could scare the general public or heaven forbid it be seen by pilots of commercial carriers. Then you have the AOPA, if any of those guys saw or got wind of it that would probably be enough to push them right over the edge. Man the switch board down at the FAA would be lit up like Vegas on a Saturday night!

[lvspark]

Perhaps a small nightscope with your std ccd at the viewfinder :confused:
I picked up a small one for $99 at the sporting goods store a couple years ago. I went outside tonight and just held my digicam up to the viewfinder... test pic below

[lvspark]

Encouraged with my test last night, I went by the sporting goods store today to see what they had..
They had a digital model around $200 with a composite video output!
Without the batteries in, it was pretty light... The specs say9.3oz but I don't know if that was with or without batteries..
I have read good user reviews on this model, with a complaint that it does not have an auto off feature :D
I have seen some online for less than $200...
http://www.weaveroptics.com/nightview/index.html

[muc]

After looking at the specs on the weaveroptics website I think they’re just using a sony ccd camera with exview. These are available as small board cameras. They include the filters to give the different colors on the LCD display. But, $200 is just a little more than what the board camera would cost so it might be worth buying just to get the LCD and other parts.

[crux12]

Hi all.

I am thinking of a way to allow a low lux camera to see at a range of 1 km in total darkness and at low cost.

Any body can help.

Thanks
:o

It can be done for about 35 grams camera and illuminators total. You do not require high powered lasers in fact I'd recommend going with lower power as they are more eye friendly.

We are discussing radio shack type of technology here and it is not that difficult once you have the components layed out.

I'm using 4-5 SMT IR emmiting LEDs (Wavelength omitted) and a low lux imager with the IR filter removed. basically image apears as if one is walking around with a high power flashlight, or flood depending upon the angle of your emmiters. Also can put a laser on target from a 100 gram gimbal, but that is yet another toy.

[cgng]

Hi. Really thanks all for your creative suggestions. I am really touch for everyone to share their knowledge.

Crux12: can you share your design. Any diagram or report to your design? What do you mean by removing the IR filter? What is the purpose for doing so? Is the 4-5 SMT IR emmiting LEDs sufficient to radiate 1 km range?

Sorry if I ask to much. Your solution seems to suit my application. Thanks

Hope to hear from you soon

[crux12]

Hi. Really thanks all for your creative suggestions. I am really touch for everyone to share their knowledge.

Crux12: can you share your design. Any diagram or report to your design? What do you mean by removing the IR filter? What is the purpose for doing so? Is the 4-5 SMT IR emmiting LEDs sufficient to radiate 1 km range?

Sorry if I ask to much. Your solution seems to suit my application. Thanks

Hope to hear from you soon

Yes ther are IR emmiters that can illuminate at that distance and further, but why do you require that specific range? What is your application?

The technology is relativly cheap ~$300 for that range with imager. However it is not something to be taken lightly. PM and give specific detail of your project and purpose. Also who is this for?

[ElectroLawndart]

What kind of field of view at 1 km are we talking about?

Dart

[Tuner]

Not to be a sceptic but I have done a lot of work with low lux cameras and removing the IR filter from them(a must for what you are doing) and using IR LEDs to illuminate the environment.

The Number one issue I have always ran into is DISTANCE. I have Used high watt 60-90 led Arrays and with lenses to narrow the beam and we were not getting sufficient illumination at 1000 meters. 100 meters ok its possibe and yes 1000 meters if you build a good reflector and/or optics and you have a very narrow area of illumnation. One problem is you will have to have some power settings for your LED becuase it will blow out the CCD when it illuminate objects close up.


Now If you use a SureFire Flaslight the M-6or4(not sure) is thier most powerful I could see this working bareley at 1 KM. Now you are flying around with a visible spotlight. Honestly make sure your CCD is sensitive in the Infra Red before you go out and buy a bunch of IR Leds.
Seriously check these flashlights out they have an excellent reflector makes for a wonderful beam expesive though.

I think the big question is WHY? 1Km that is a strangely long distance. I could see 100meters but a 1000??

If you need help with this I can point you to some great sources for GOOD IR LED. Roithner Laser Tech is one, its in germany.

Scott

[Nixie]

It takes a lot of energy to light up a large area at night.

A kilometre, if I may say, is a bit ambitious. But if you really must get such long range views at night then you might try a regular lamp of say 800 watts (normally 66 amps at 12 volts) and pulse it on for 10 milliseconds, during it's time on, take a pic. By pulsing it on for 10 mS every second you can save energy, have a much smaller battery, get a distant view, but you are only able to have a set of images which will appear quite 'flickery'. There's a number of problems with this idea, but I think you get the idea.

One problem is that a much smaller battery won't be able to provide the 66 amps you need for 10 mS, so you'd need to use something like a supercap to store energy and discharge the supercap's energy into the lamp.

BTW, a laser won't light up the night sky. They are only a few milliwatts and don't have sufficient energy to illuminate a large area.

A Xenon tube has a huge amount of energy, but only lasts for less than a millisecond or so. They are great for cameras at night, but unless you get one that is much higher powered it would be nearly useless. They are available in a big variety of powers.

IR could be the best option. Pulse an IR lamp and take pics during the on time. But remember it's monochrome.

[Unterhausen]

if you need to see a kilometer away, why not fly over there and look?

I saw a lecture where it was mentioned that you could get laser range finders that weighed a few ounces. I guess that was something that only measured the distance at a point. I've been looking since then, and the only flying ladar I've seen was (i think) Carnegie Mellon flying with a Sick on their giant yamaha helicopter UAV. Since a Sick weights about 10lbs, I guess that's not a solution for most of us. Sick rangefinders measure the distance in a plane for 180 degrees.

[joelhaasnoot]

Hey,
I've come across several links to this before. Apparently, you can mod USB Webcams and remove the infrared filter. Add some infrared LEDs, and you might be able to get some cheap infrared shots. One link is here:
http://homepage.ntlworld.com/geoff.johnson2/IR/
But just google 'infrared webcam photography' and lots of hits come up.
I have also seen people do this with the PV2 Digital 'Disposable' Cameras that have been hacked to be reusable (http://camerahacking.com)

[Tuner]

Infra red is a tricky term. They are techninally Near Infra red. 780-820nm wavelenght range. witch is just outside of the red but not quite infra red.