Infrared Webcam HOWTO

Geoff Johnson writes "Some of the Slashdot readers may be interested in this page I put together. It describes how to make an ordinary webcam see in the near infrared waveband."

Comments

duh

[oliverthered]

Let me guess, remove the IR filter from in-front of the lens.

Re:duh

[m50d]

Well, and replace it with one to block visible light. But yes, that's about it.

Re:duh

[oliverthered]

You don't need to for 'night vision', which is what I expect most people will be interested in.
Full colour (maybe a tiny bit washed out because of the extra IR) during daylight, and at night switch on the IR light and you've got an IR camera.

Near IR isn't that interesting, except humans cant see it, what would be cool is if the chips could pickup far IR so you could see heat.

Re:duh

[budgenator]

Cadillac has an interesting thermal system, I haven't really dug into it in depth, but basicaly the sensor is a bunch of capacitors similar to a ccd sensor. When the IR image is focased on the sensor, the heat causes the diaelectric between the capacitor plates to warm up and expand changing the charge on the capacitor and make it readable.

Sooner or later someone is going to hack the system for some serious geek factor. I could see someone hackering several of these different systems together for some cool false-color IR video. I used to do quite a bit of IR photography used Kodak's IR false-color slide film, green showed up as blue, red was green and IR was red if memory serves me correctly. The biggest problem was the film used the old-fassioned E4 process, so you either had to send it to Kodak or do it your self

Re:duh

[oliverthered]

Lots of things work, you can easily buy a IR pass filter.

I I've used purple sweet wrappers in an IR remote control, and often the plastic in the housing is good enough to block most visible light but pass IR.

Re:duh

[huge colin]

Cadillac's system was actually a Barium Strontium Titanate (BST) module, developed by Raytheon. It required a thermal differential in the scene from frame-to-frame to be able to see anything, and thus a "chopper" wheel (a rotating slotted disc) had to run in front of the detector. The picture would smear and was generally low-quality. The module used by Cadillac was also rather low resolution (160x120, I believe).

The alternative to BST is microbolometer technology, developed by Lockheed Martin / BAE Systems and others. A microbolometer array consists of vanadium-oxide bridges that vary their resistance when exposed to thermal radiation. The scene will occasionally need to be "shuttered" (i.e., zero all the pixels against the back of a shutter mechanism to cancel the thermal drift that creeps in over time.)

Unlike light-amp, true thermal imaging allows you to see in complete darkness. And unlike projected-IR, it isn't limited in range by any kind of IR-transmitter. And unlike either of those technologies, it allows you to very quickly find humans (or other mammals) in a scene, and it allows you to see where things used to be by the heat-shadow that they've left.

Can it see through clothing?

[Anonymous Coward]

Cause I'd really like to take my PC to the beach and get webcam shots of da honey's.

Re:Can it see through clothing?

[Anonymous Coward]

Im sure they wouldn't find anything suspisous about a guy with a laptop with webcam attatched.

Re:Can it see through clothing?

[anagama]

This was covered on slashdot a long time agao.

But yes, it can see through clothing to some extent.

infrared wecam!

[Anonymous Coward]

that's just fantatic!

Night Vision Linux Webcams All the Rage?

[filmmaker]

Infared web cam? Somehow I don't think Bubble Cam would be quite the same at night. :D

I do wonder what the most common applications for Linux/IrDA are, considering the trend I've observed where among the most commonly requested Linux HOWTOs recently have been 'laptop', 'infrared' and 'webcam'. Is everyone building infrared webcams?

cached link of video if it dies.

[Organized Konfusion]

http://homepage.ntlworld.com.nyud.net:8090/geoff.j ohnson2/2004-08-08.avi

The WEcam...

[mindriot]

...and, soon to come, the THEMcam!

SCNR... sometimes I'm amazed at what kinds of typos make it through to the frontpage.

But besides that, very nice article. I personally found IR very useful for some surveillance-type situations. A few years ago, my father set up an IR-sensitive camera and an IR diode in a birdhouse in our garden, which allowed us to watch the new-born ones without creating any disturbance.

Burgler Cam??

[GreyPoopon]

Does anybody think that coupled with a pure IR source of light this item would be useful in catching would-be prowlers without alerting them? OK, probably a stupid idea...

Re:Burgler Cam??

[shic]

There is a lot more to the idea of video security than the simple "alerting" or "non-alerting" you suggest.

For example, using your example of a car - I'd consider myself a madman if I opted not only to have a car alarm - but also to make it as obvious as possible that I am equipped with one. The snag, however with alerting alarms is that after a few "false alarms" it is widely understood that alarms signals will be ignored - people assume it is a technical fault... and the criminals know this too. Another problem with the alerting alarm is in automatically deciding at what point to take issue with someone's actions. For example, I'm aware of areas in which organised youths check all the car doors in a neighbourhood - hoping someone has forgotten to lock and alarm their car. Under these circumstances an alarm system does no good... It is important to discriminate... Burglar alarms also offer no protection from vandals - whereas a CCTV with night vision may well do - if only by identifying weaknesses in manned security. I imagine an infra-red video surveillance system would be an extremely good way to improve security for applications such as monitoring business car parks; monitoring entranceways to identify where layabouts trespass before any real harm occurs - as well as providing some way to counter graffiti tagging and other illegal unpleasantness.

I've long thought this would be a fun project - but as yet I've not found time to tinker.

Not all cheap webcams have filters.

[OneDeeTenTee]

If you're lucky the webcam won't have an IR blocking filter.

You may want to check it with a remote (or just put your IR passing filter in front of it) before you take it apart.

Re:WEcam HOWTO?

[InfiniteWisdom]

I've heard of a webcam, but never a wecam.
Hence the HOWTO, duh!

OK.....

[mr_z_beeblebrox]

So the article details a cool hack, props. What I want to know is.....why was I able to download the 6.9 MB AVI file at the end. Isn't his server supposed to die or something? I can never download the files referenced by a /. link. Is something wrong?

Re:Infrared Technology and the Chinese Threat

[nounderscores]

Lets hack some cams, stick them on $89 lcd handheld tvs and send them to tibet as freedom fighter nightvision goggles.

It might make the fight more interesting.

this is true of almost all modern cameras..

[Mark19960]

altho, most that ive seen ahve the IR filter directly attached to the CCD.
you would remove the CCD, then remove the 'piece of glass' from it.

some cameras achieve this effect differently, I have not quite worked out how they work.
For example, Sony camcorders that have 'nightshot'
also have an IR filter, but I suspect its something different. the switch not only engages some IR illuminators, but does something in the lens block itself. (switches something in/out mechanically)
I know that the IR filter at the CCD remains there, its in a fixed position.

I am now curious and have to dissasemble a sony lens block to see :)

I used to work on cameras, and I have removed the IR filters on cameras before for a bit of fun.

if you can get enough IR leds going you can get it pretty well lit.
Altho, the resolution is probably not going to be that great at a distance.

X-Ray Specs

[lildogie]

Wow, just like those funny glasses I bought from the ad in the comic book back in the 60's.

Re:Infrared Technology and the Chinese Threat

[budgenator]

Actualy this is pretty much WW-II style technology, the old Sniper-Scopes used active IR like this web-cam mod. Now the problem is passive IR is so common firing up an IR illuminator is like painting a bull's-eye on your forehead. It's so common, we put blue filter on our flashlights to block the near-IR and IR output; visible light is less damgerous the IR at night!

The day is still young...

[Shazow]

Everyone is still asleep from their late-saturday-night D&D sessions.

Give it time... :-)

One question

[gone.fishing]

Will this mod void the warranty?

(it's funny, laugh)

Look for heat loss?

[crow]

Will this capture the right range of infra red to detect heat? If so, then I could see using it with a laptop on a cold day to see where I need to improve the insulation on my house.

trashed my kensington videocam

[emptybody]

I unscrewed the lense end - the same way you fine tune the focus.

it then proceeded to fall over due to the usb cable coming free in back.

I now have a little stack of lenses that I need to figure out the proper way to orient.

2 lenses - 2 ways = 8 combinations.
a third lense further out = x2 more combinations.
a fourth lense on the outsite = x2 more combinations.

Total 32 possible ways to re-assemble this little bugger!! DAMN-YOU!!!!

Worst of it is, the pink lense is a lense and not a flat glass filter. I cant use this cam :(

Anyone have a blow-up of this cam -
Kensington VideoCAM VGA PC Camera
Model#67015

Disgruntled ISP customer?

[The-Bus]

This guy must just be mad at his ISP or whoever does his hosting.

The ~7MB video file at the end of the page doesn't even have anything to do with IR video. It's like he wants us to take the server down.

So do him a favor and just download it 8 times.

If you want a time-lapse capture app for free...

[maird]

...Get one here: http://www.mair-family.org/Downloads/ Geoff says the software he had isn't very good. I couldn't find anything I was prepared to pay for so I wrote my own and publish it at that link. Sorry Windows only and WMV output. You can read the feature list for yourself but, in terms of Geoff's difficulty, it will capture frames at between 4s and one hour per-frame (configurable) and create a 15fps WMV.

Go ahead, /. my web server...Hopefully my ISP is tolerant.

alternative approach

[tverbeek]

Or just accelerate your webcam enough (toward the object you wish to photograph) to blue-shift the infra-red into the visible frequencies. Put it on a really-high-speed ferris wheel or merry-go-round and synchronise the snapshots to its rotation if you want to keep it "stationary". Compensating for the doppler shift in the signal from the camera is left as an exercise for the reader. But no disassembly or modification of the camera needed!