Technology

How to use your Video Camera as an Infrared Detector

Many modern video cameras have a “night” mode, which allows grayish video of close subjects to be taken, even in utter darkness. This feature means that such video cameras can be used as infrared (IR) detectors–they can pick up infrared light that is invisible to the human eye.

The video camera I’m using today is a Sony DCR-SR45. It’s not a high end camera, and I purchased it used, but it has “Nightshot Plus,” which I’m interested in today.

Here’s how the night mode works on these cameras:

1) An infrared light on the front of the camera illuminates the subject with infrared light. You might see the near-infrared output of this light as a faint red glow if you look directly at the video camera when it’s in night mode.

Infrared light source on video camera

2) The infrared sensor in the camera picks up on the reflected IR light to render the picture. If you’ve ever used such a camera, then you know the video it produces when you’re using night mode is grayed out and looks something like the following:

Nightshot Mode

So what can we do with this IR detector? Well, one of the easiest things we can do is check if our TV remotes are working. Most TV remotes work by broadcasting an IR signal to the TV. To the naked eye, this IR light is completely invisible, but not to our IR detector. Check out the side-by-side video captures of a TV remote without and with night mode:

IR remote through video camera with nightshot

If you want to try it for yourself, just point the TV remote at your video camera (which should be in night mode) and press a button on the remote. If you’re watching the screen on the video camera, you should see the little bulb on the tip of the remote turn into a rapidly flashing light.

To the naked eye, the infrared light from the TV remote should be completely invisible, but even video cameras without night mode may detect some infrared light (see the left picture above). Turn it into night mode, however, and the IR emission from the remote becomes practically blinding.

Another interesting use for your IR detector is to tell from a distance whether a heat source is radiating thermal energy in the form of IR radiation. Recall from physics class that heat is transferred three ways: conduction, convection, and radiation. If you run really hot water through a faucet and take a look at it through a video camera on night mode, you won’t notice anything unusual. This is because the hot water isn’t transferring much heat through IR radiation. If you hold your hand close to the stream of hot water you won’t feel much. Touch it, however, and the heat from the water is conducted into your hand. Now take a look at a radiative heater through your IR detector, and you’ll see something interesting. In regular video, the heat source in the heater appears orange but it’s well-defined. Turn on night mode, and the heat source turns into a bright diffuse glow. It’s particularly interesting, to watch such a heater warm up through a video in night mode. When the heating tubes (or coils) are cold they look well defined (but monochrome) in the video. As they heat up, they become enveloped in a diffuse, white glow.

Visible-IR Comparison of Radiative Heater

If you’re the nefarious type, you may find our IR detector very useful. Security cameras with nightvision capabilities usually illuminate their field of view with infrared LEDs. To the naked eye, this illumination is invisible, but point a video camera with night mode toward a house with nightvision security cameras, and those security cameras stand out like spotlights.

One thing I haven’t tried yet is to point the video camera in night mode toward a circling police helicopter to see if they’re using an infrared spotlight to illuminate the ground. Some day I’ll check it out. I’ve always been curious whether or not our local police chopper uses IR technology to track suspects.

Categories: Poor Mad Science, Science, Technology | Tags: , , , , , | Leave a comment

The Technology of Elysium

On Saturday night, my fiancee and I watched Elysium–the new sci-fi blockbuster featuring Matt Damon, Jodie Foster, and one or two other people. The word on the street is that Elysium carries a message about social disparity. It does, in an over-the-top and in-your-face manner. Personally, I think the “message” would be a little more impactful if it was a lot more subtle and nuanced. Anyway, enough about the social satire aspect, I want to talk about the technology of Elysium.

Image credit: Media Rights Capital and TriStar Pictures

Image credit: Media Rights Capital and TriStar Pictures

Exoskeletons

At one point, Matt Damon’s character puts on an exoskeleton suit and proceeds through some merry bad-guy pulverization. The powered exoskeletons depicted in the film are not that far from reality. Already, several companies have working prototypes of such suits. All that is really needed for the movie exoskeletons to become reality is the development of compact, mobile, and powerful power supplies to power the suits.

Cylindrical Surveillance Drones

At another point in the film, Matt Damon’s character is hunted down by nearly flat, cylindrical, unmanned, surveillance drones that look like miniature flying saucers. This technology could already be out there. Think a quadcopter in a cylindrical housing.

Image credit: Media Rights Capital and TriStar Pictures

Image credit: Media Rights Capital and TriStar Pictures

Police/Military Robots

The police/military robots in Elysium were very human-like in their behavior and fighting tactics. They didn’t have faux human hair or skin (i.e. they were obviously robots), so it’s not like their anthropomorphism was designed so they could be passed off as human. What then was the point of having them fight like measly humans? If the military develops fully autonomous fighting robots, I don’t think they will do uppercuts or roundhouse kicks. If they have appendages, they won’t be arms and legs, they will be guns, bone saws, and other more effective fighting limbs.

When fighting another human, it is reasonable to assume that decapitating him will result in the immediate cessation of all attempts to kill you. Not so with murderous robots. When Matt Damon’s character tore the head off of a military robot, I couldn’t help but wonder why he assumed the the robot’s computer and sensors were all located in its head.

Quite a few companies are working on human-like bipedal robots, and a few of them have build pretty amazing prototypes. The possibility of seeing them on the battlefield in the coming decades is not out of the question. However, I don’t think modeling them after humans would make the most effective killing machines.

Programmable Guns

In Elysium, Matt Damon’s character uses a gun that fires explosive rounds. Better than that, the rounds explode at a preprogrammed distance, making it possible to take out enemy soldiers even when he doesn’t have direct line-of-sight. Possible? Done! Yes, I know it’s scary.

Airborne Machine Guns

One of the bad guys in Elysium pecks at the good guys with a pair of rather boring machine guns on his space-capable shuttlecraft. They should have used something more impressive–something truly terrifying–like the M134 Minigun. I shiver every time I watch a video of that thing in action.

Elysium

Image credit: Media Rights Capital and TriStar Pictures

Space Station

The best tech of the film is, of course, the giant wheel of a space station. Artificial gravity is generated by the slow spinning of the wheel. Good so far. The ‘coolest’ aspect of the station is the open-to-space atmosphere. This allows shuttles from Earth to land right in the middle of grassy lawns on Elysium. Amazing, yes, but is it possible? I am not a physicist (yet), but I have my doubts about the viability of such an atmosphere.

Wouldn’t the solar wind blast the atmosphere away? Well, not necessarily. The station isn’t that far from Earth so it’s probably within the protection of Earth’s magnetic field.

On Earth, gravity keeps our atmosphere wrapped tightly around the planet. Elysium has gravity too, but it’s a fake gravity. It’s not the gravity caused by mass, rather it’s a pseudo-gravity caused by centripetal force (the spinning of the space station). Would this fake gravity be sufficient to keep the station’s atmosphere on the station? Would inertia and friction be enough to keep all that atmosphere from dissipating into space? To be honest, I don’t know.

Another potential problem is ultraviolet radiation. On Earth, our ozone layer protects us from the majority of the sun’s UV rays. Unfortunately, the Elysium creators can’t just inject a shitload (yes, that’s a scientific measure of volume) of ozone into their atmosphere because that stuff is pretty harmful to plants and animals. Earth’s ozone layer is many miles above the surface, so there’s no worry about breathing it in, but Elysium’s atmosphere is not deep at all. The people on Elysium could live without the protection of an ozone layer. All they would have to do is hop into their fancy medical scanners every few hours to get rid of their nasty sunburns. The plants, on the other hand, wouldn’t have that luxury.

Summary

Given current science, I think a lot of the tech depicted in Elysium is doable within decades. Some exceptions would be the medical tech and the shuttle propulsion. I’m not sure how those could be accomplished within the next 150 years, but of course that’s no reason to throw it out of science fiction.

All in all, I think Elysium is a pretty decent sci-fi movie. The storyline isn’t even close to the utter greatness of something like Star Trek (not the recent movie, I hated it), but it’s a good depiction of some of the technology that humanity is on the verge of developing.

Have you seen Elysium? If so, what did you think of it?

Categories: Technology | Tags: , , , , , , , | Leave a comment

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