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

Re:duh

[m50d]

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

cached link of video if it dies.

[Organized Konfusion]

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

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.

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:Not all cheap webcams have filters.

[Zinob]

In fact it does at least mine, but its quite crappy (besides IR is a bitch to block perfectly, haven't seen a single filter that is able to kill to 100% of it, so you will see a remote even though your camera has one). On my QuickCam express it is located behind the rearmost lens i.e. the one located closest to the sensor (which it glued to the housing) so you have to (carefully) pry that one loose (i used a really small screwdriver and an awl), then remove the little clear square of glass behind it (looking just as in the pictures(!)), and wollá! You have even better reception of IR (err considering the quality of the CMOS sensor i guess i should say "less bad").

Many high-end web-cams have day/night and pan/tilt

[Anonymous Coward]

We've been buying VB-C50iR cameras from NuSpectra for construction monitoring. We can do all this--perhaps not as cheaply!

Pan/tilt/zoom control, day night filter (changes to IR/Night mode on a schedule)... Plus 26x optical zoom rocks.

NuSpectra has a demo camera out of their office in San Francisco.. See demo in upper right corner of page.

We also use the SiteProxy software that lets us build time-lapse movies from all the camera's preset positions on the fly.

Check em out!

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: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.

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.

Re:The effects of IR on follicles

[Fishead]

What's really cool is looking at a person through a 3-5 Micro-Meter (aka "Far IR" thermal camera (think military and very expensive). Your hair looks black near the ends, and red near your scalp. Glasses appear black, veins are sometimes visible, and you can see 2 guys in a zodiac up to 20 miles away (which is why the military likes them so much).

This webcam mod is pretty cool, but only for us normal folk without $40,000 to spend on a REAL thermal camera.

See through camera

[MaxBlue]

Didn't Sony have an issue a few years back with their digital camera's seeing through bathing suits? Wasn't it have something to do with IR?

Was their fix to add IR filters?

Re:Look for heat loss?

[SmurfButcher Bob]

Nah, you don't need to spend that much. You can bottom-feed off the low end for about $13 grand for a fixed-notch greyscale bolometer type. Better ones will run up to 20 grand, and offer a full floating, variable width notch with false color representation.

Granted, these are all intended for structural firefighting, so they aren't cheap. But they *are* intended to be dropped, kicked, and roasted. Obviously, you'll trade weight for battery life and heat shielding - the Draegers have full Ni cladding and can survive long exposure, but they weigh a lot. The Scotts are much lighter, but don't get them above 600 degrees...

Warning: state of USB webcams on linux

[jago25_98]

I bought a sweex webcam like the one in the guide.

Indeed the usb chipset is supported (sn9c103), but the sensor isn't. So I'm sending it off to Italy for Luca the developer, well it's no use to me.

USB webcams can have different sensors within the exact same model, so you never really know when buying one whether it will work for sure.

Hopefully this will change if the USB video standard (similar to firewire video standard), comes about.

In the mean-time think about firewire cameras.

tried it(using just swiss) but whitout the film

[esoinila]

Hardest part was putting the Logitech QuickCam back together the right way -- because which ever way which part was was quickly forgotten in the process. I didn't have any film handy but the cam now shows security marks on 50 Euro bill quite nicely. The picture is more of black and whitish without the filter. It sees through things.

Now just good lighting. I have a bicycle led-light with individual lences for each led. One of these with proper leds might work nicely as home surveillance system.

But sure was and is fun....much thanks to the author.

Re:Burgler Cam??

[ebob]

Not so stupid.

A couple of months ago a guy in rural San Diego did exactly that and nabbed some identity thieves stealing folk's mail from their mailboxes at night. Here's the story from the San Diego Union Tribune:

http://pqasb.pqarchiver.com/sandiego/

Re:Burgler Cam??

[deacon]

Sure. But if you want to step up in image quality and view range:

Use this camera, illuminate with this device and use a C-mount lens from this page if you are comfortable with removing the electronic iris in some of these older, but superb qulity, lenses.

You will be able to read a license plate at 75 feet in complete darkness.

Their fix

[Anonymous Coward]

What they did was disable all the camera's exposure control and a few other features when night mode is on. That means that if you try to use the night mode in the day, the image is completely trashed.

There are ways around it, though. The main one is to add an IR-only filter to the camera so that it's dark as if it were night, and to stick one of the switches halfway, or solder it.

Re:duh

[budgenator]

basicaly the E4 process you expose the film

1. develope it the reduce the exposed silver halide crystals to metalic silver( results in an negative image)
2. bleach out the exposed silver( removes the negative image)
3. remove the film and expose it to light which exposes the undeveloped silver halide crystals
4. re-develope the film to reduce the exposed remaining silver halide crystals to metalic silver resulting in an positive image
5. fix the film to remove any undevelopes silver halide crystals
6. the silver reacts with the dyes in the film to become visible as color pixels

this results in a postive image or projection slide. The false color means the colors on the film don't represent reality.

Re:See through clothes!

[shish]

He has a picture of himself in a multicolour top; it shows up as a solid colour, but not see-through :(