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Infrared X-Ray Camera

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"I see you, a thief on the roof. My new satellite link has both infrared and the x-ray spectrum. I see your heart beating. I see you are afraid."
Gunther Hermann, Deus Ex

Whenever someone calls for the infrared camera on TV shows and film these days, either the handheld version or one mounted on Spy Satellites, the device will have amazing qualities, chief among them being able to see through walls. It's incredibly convenient for the good guys being able to make out what's happening inside the building. Sadly, real thermal imaging infrared cameras don't work like that at all. Heat simply doesn't go through walls in such a way to form a picture. Walls are generally supposed to stop heat from getting through them, which is why they are insulated. In fact an infrared camera meant for thermal imaging (as opposed to near-infrared), the kind most often seen on TV and movies, cannot even see through a sheet of regular glass that's perfectly clear to anyone using the Mark One Eyeball (this is the effect greenhouses are based on). Anyone looking at a sheet of glass with a thermal imager is more likely to see their own reflection. Steam is not good for IR either, but any light fog (which is usually cool) could be penetrable to an extent.

The truth is plainly obvious from all those televised high-speed chases in Los Angeles where the chase takes place at night so the Forward Looking Infrared camera on the police helicopter gets to show the Cool High Tech imagery. You can see the heat of the car engine, the tires, the ground where something hot has been, even the reflection of heat off the ground, yet you can't see the driver and his passengers although the few millimeters of metal making up the car body is a lot thinner than the several inches of material making up the average house wall. Not to mention, it conducts heat better. One can therefore conclude that either writers and directors don't watch Fox, or that it's yet another case of technology gone awry in the service of the plot.

The infrared spectrum is over three thousand times wider than the visible spectrum (visible = 400nm to 700nm; infrared = 700nm to 1,000,000nm) and has substantially different properties depending on which part of the infrared spectrum you are at. The infrared spectrum is typically divided into four groups:

  • Near-infrared (wavelengths of 700 nm to 1400 nm): Produced by objects that are glowing hot (light bulbs, the sun, fires). Most "night vision" cameras use this because the sensors are cheap (just stick a visible-light-blocking filter over a digital camera sensor) and because you can illuminate an area with IR-emitting LEDs without anyone noticing. Most greyscale night images are using this part of the infrared spectrum. Glass is quite transparent to this, as are many lightweight fabrics (most notably, those used in swimsuits). Metal reflects it, and most opaque objects block it. If you assume it behaves like visible light, you usually won't be wrong.
  • Mid-infrared (wavelengths of 1400 nm to 8000 nm): Produced by objects that aren't quite glowing hot (jet engines and the like). Used mostly by heat-seeking missiles.
  • Long-wave or thermal infrared (8000 nm to 15,000 nm): Produced by objects that are at "reasonable" temperatures. This is the band that is used by heat-detecting cameras. These cameras are quite expensive, and need to be cooled down below the temperature of the environment (otherwise, they'd see themselves rather than the world around them). Most solid objects will block or smear the IR from objects behind them, while adding their own heat to the mix.
  • Far infrared (15,000 nm to 1,000,000 nm): Produced by cold objects (think "liquid nitrogen" cold) and by specialized scientific equipment. Not much practical use.

Note, however, that there theoretically exist wavelengths on which the electromagnetic radiation behaves similarly to this trope. That's high-frequency microwaves (down from centimeter range), and imaging radars that use them. They are, however, very complex and expensive and are used only in some very specialized fields. Just one example would be the terahertz radiation (T-rays), which sits uncomfortably on the border between infrared and microwaves. It's hard to produce and hard to detect, but most non-conductive objects (walls, clothing, etc) are transparent to it while most conductive objects (metal, the water in your body) reflect it. Terahertz sensors (which, as noted above, have more in common with radars, rather than with the cameras), are already being used for airport security in a number of countries, and known as "nude scanners".


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    Anime & Manga 
  • Mobile Suit Gundam Wing is quite guilty of a variation of this, with heat sensors able to tell whether a mobile suit is manned. In space. Through several feet of armor. In a cockpit that is insulated enough to allow it to remain at a comfortable temperature even in space. Mobile suits have fusion reactors as well. And rockets all over. As well as using high-powered beam weaponry. But no, apparently the only source of heat on a mobile suit comes from the pilot.

    Comic Books 
  • The thermal vision in Batwoman's cowl works this way, though it doesn't produce crystal-clear images.

    Films — Animated 
  • Occurs in Lilo & Stitch when Dr. Jumba Jookiba tracks Stitch inside a dog pound via a pair of infrared binoculars. Possibly justified due to alien technology.

    Films — Live-Action 
  • Aliens: Averted, as the Aliens don't show up on infrared at all. It's also done as a bit of a gag at this trope's expense, as the Marines realize this while the Aliens are right in front of their faces, and completely invisible. This is carried over to the Alien vs. Predator franchise with the Predators being forced to switch between different modes to even spot the Aliens.
  • This was definitely popularized by, and may have come from, Blue Thunder and its TV spinoff, in which the eponymous super-copter mounts IR sensors that do precisely this. The infrared scanner can see through walls and shows the results on the usual color-coded display screen in the cockpit. One notable example from the series has the camera looking through the wooden walls of an old barn to detect an aircraft with a suspiciously warm engine.
  • Played straight in Eraser with the EM-1. Not only can the scope see through walls, but it also sees through people to specifically target a beating heart. It's notable that anyone can see the green spotlight that is, basically, the weapon's equivalent of the red dot. Kruger is able to hide himself and the witness by hiding behind a fridge. Presumably, both the metal and the cold foil the scope.
  • James Bond:
    • Averted in Thunderball. The camera Q issues to Bond just lets him take pictures of the Disco Volante's exterior, albeit in the dark and underwater.
    • A real Infrared Xray Camera appears in Licence to Kill, which Pam Bouvier nearly shoots Bond and Q with. It prints out an infrared xray picture of their two skeletons dodging for cover.
  • Navy Seals (1990): The SEAL Team sniper uses a .50 caliber rifle with a thermal scope with these miraculous capabilities. His call sign is (appropriately) "God".
  • Predator:
    • In the original Predator, this is subverted. Dutch realizes that the creature sees in infrared when it can't spot him covered in (cooler) mud which temporarily disguised his body heat. When the film shows scenes from the Predator's point of view, the body heat of the humans is blocked by cooler objects in the foreground such as vegetation, just like it really would be. However, in real life, the mud would warm up due to the body heat pretty quickly, as demonstrated by the MythBusters.
    • In Predator 2, however, a variant is seen where the Predator picks up a woman and after a black-out implying a switch, sees a fetus inside of her.
    • In Predators, it's stated that the Predators are learning to adapt; when Adrian Brody tries to use the same tricks as Dutch, the lead Predator switches vision modes to a heartbeat sensor.
  • Used in RoboCop (1987) to surreptitiously pinpoint the location of a hostage-taker; after that it's just a matter of reaching through the wall and grabbing.
  • Not a camera, but the monsters of Tremors 2: Aftershocks see in infrared. And subvert the usual X-Ray properties assumed to go with it; at one point the heroes hide themselves by holding doors in front of their bodies while moving, making themselves nigh-invisible to the beasties. A character also hides in the bucket of a backhoe which, as the monsters are short, they can't look over the sides to see into while milling around.
  • xXx: Xander uses special binoculars to peep through things, including a wall.

  • The Executioner: In the Phoenix Force story "Tooth and Claw", a KGB hit team tracks down Gary Manning to a hotel room and use one of these to spy on him, only to find he's suddenly disappeared from the screen. On investigating they find a mannequin with a remote-control battery-operated thermal unit that distributes heat to various parts of the 'body'. They also find a Booby Trap...
  • Fate/Zero: A dual-scope setup is installed on a WA2000 sniper rifle (that uses a tripod, no less) by the Cold Sniper Emiya Kiritsugu, the "Magus Killer"; one is night-vision, the other thermal. Done somewhat correctly, as it's used to track Magi, who when using magecraft will have an increased body temperature from the Circuits. The target in question is about 300 meters away, and the sniper switches over to night-vision to confirm his target before lining up a shot.

    Live-Action TV 
  • In 24, CTU (usually Chloe) regularly sends Jack a rundown of the occupants of a particular building and what their current location is, all by using infrared satellites.
  • A fourth season episode of Buffy the Vampire Slayer has the Initiative using an infrared scanner to spot the vampire Spike through the walls of a dorm. Doubly implausible in that his "room temperature" signature actually shows up as a blue spot, against the background heat of the room.
  • Burn Notice:
    • In an episode where Team Westen deals with a Mafiya human-trafficking ring, Fiona uses one of these to scope out the interior of a Russian restaurant. Sam asks where she got it; apparently her neighbor is a peeping Tom.
    • In another episode, a regular digital camera is used to spot the infrared laser being bounced off one of the apartment's windows in order to eavesdrop on Michael. In such a system, the laser can measure vibrations in the glass and output it as sound from inside the room. This is Truth in Television to an extent; digital cameras can see otherwise invisible infrared; point your remote at your camera and push a button while looking at the screen. Glass is opaque to infrared but plausibly the intensely focused laser may get some through.
  • In CSI: Miami, it is used to look into a boat.
  • The first episode of the second season of Knight Rider falls right into this trope; because the actual x-ray camera doesn't work through leaded plates, Michael needs to use a modified version of the infrared camera to see what's going on inside.
  • A Law & Order episode uses infrared scanner imaging to secure a search warrant on a mosque. The defendant's lawyer successfully argues that the technology violates the Fourth Amendment without a warrant specifying its use and gets the evidence seized there thrown out.
  • An episode of MythBusters shows the inability of infrared to look through glass when an infrared sensor is spoofed by placing a small pane of glass in front of it, allowing access to a monitored hallway. On the other hand, another episode shows a thermal infrared camera able to see through a dust cloud that obscures visible light. It isn't until the team uses a set of CO2 extinguishers to obscure body heat that they're able to fool it.
  • In NCIS, it is used to look through the walls of a house.
  • This is subverted in the NCIS: Los Angeles episode "The Watchers" when we find out that Hetty installed heaters in the roof of the boatshed to prevent this.
  • NUMB3RS used a variant when body-heat signatures pinpointed survivors trapped in the wreckage of a train crash. Arguably might've been justified, in that Charlie sent small camera-armed robots into the wreck to observe the trapped victims directly, rather than through intervening walls. Unfortunately, the signatures of two unlucky victims vanished within seconds of their demise, whereas a real body's heat would take many minutes to disperse.
  • The X-Files: The episode "Fallen Angel" features invisible aliens, and one of them is seen through a heat-source sensing device through walls.


    Tabletop Games 
  • Many species in 1st and 2nd Edition Dungeons & Dragons have "infravision"; the fifteen years of arguments and debates about how exactly this power worked and what you could and could not do with it led to the "darkvision" power in 3rd edition.
    • Darkvision is itself unrealistic, as it apparently shows shapes just fine but lacks color information... which actually acts more like sonar than anything else! This does, however, provide an interesting explanation for Dwarves' predilection for carved runes — writing on paper is a color difference that is not visible to darkvision, while chiseled runes (which have a depth difference) are.
    • Alas, many Tabletop Games took their inspiration and many of their buzzwords directly from 1st edition, so it's exceedingly common to find "infravision" in any non-realistic game. The arguments continue, of course.
    • Creatures with infravision usually are also described as having glowing eyes when it's active. Granted, some illumination wouldn't hurt if they want to see walls, but how it can work in eyes...
    • And that's nothing compared to the races who instead got "ultravision", the ability to see via ultraviolet wavelengths. Ah yes, the ability to see by direct starlight...
      • Which became simply "Low-light vision" in 3rd edition, and is simply an improved ability to see in dark conditions (like what cats and other nocturnal animals actually have).
  • Mutants & Masterminds averts this trope, noting that it works largely like regular sight and is blocked by walls (although they fail to note that glass blocks it), only allowing Infravision as an alternative to regular sight. Of course, it is possible to get Penetrates Concealment Infravision by paying a few more points but this is also a game where it's possible to get Eye Beams, so physics has little to do with it.

    Video Games 
  • The Alien vs. Predator games force the Predator to switch between four vision modes (one of them being normal human sight, probably for gameplay purposes) to highlight enemies; the IR scan won't highlight Aliens. Later adopted in AVP: Alien vs. Predator, where the Predator is distinctly shown switching vision modes to track Aliens instead of humans. The later Alien vs. Predator game also has three vision modes (normal visible light, infrared, green vision thingy) in order to see humans and aliens when they try to hide, but neither can be seen when they are behind walls.
  • Nanovision in Crysis 2 is a combination of night and infrared visions that can see through dust and smoke (not perfectly, but still better than the naked eye).
  • Smart vision in Deus Ex: Human Revolution, in keeping with the Shown Their Work theme for the workings of augmentations, explicitly uses the previously mentioned T-rays which can feasibly behave this way. From the in-game description: "...provides the implanted prosthesis with the ability to match visual silhouettes and body kinetics to micro-thermograph and t-wave lens modules, thus providing a limited degree of “x-ray vision” through walls and light cover."
  • F.E.A.R. 2's elite power armor has a fairly realistic false color thermal imaging mode; it doesn't exclusively show people, as fire and other power armor (which are incredibly heat inefficient) also shows up.
  • The thermal vision in Ghost Recon: Advanced Warfighter doesn't see through cover, although the HUD can display the sillhouettes of concealed enemies that have already been spotted by other means.
  • In Ghost Squad, you can actually use the infrared goggles to snipe through the walls of a straw hut. Why they had infrared goggles on a daylight mission is left unanswered.
  • Averted in Metal Gear Solid 3: Snake Eater. The thermal imaging scope cannot see through obstructions.
  • Downplayed in Metroid Prime, as the thermal visor can't see mechanical targets (turrets, drones, etc.) or things you've shot with the Ice Beam, can be overloaded by enemies that generate large quantities of heat, and is mostly (but not completely) useless in lava areas. You can see electrical conduits in the walls, though - evidently the Space Pirates bought really cheap wire and/or put too many appliances on the circuits. The cheap wiring fits with evidence the Scan Visor gives in Metroid Prime 3: Corruption that the Space Pirates seem to cheap out on maintenance quite a bit.
  • Perfect Dark has the X-ray Scanner (which can see through walls) and the IR scanner (which can show cloaked enemies). Both are useful, but limit the player's field of vision.
  • Most of the Rainbow Six games avoid this. Infrared goggles and thermal scopes don't see through anything solid, and the vision gets less distinct as distance increases. Enemies further away will be only slightly brighter colors than the background haze, and if sufficiently far will blend in entirely. They are mostly useful for seeing enemies in smoke-filled areas.
  • Averted in Shadow of the Tomb Raider, as the game explicitly says that IR-equipped enemies can't see Lara through walls. Lara can also smear herself with mud to mask her own heat signature.
  • Silent Scope 2 has both a thermal scope and an X-ray scope. Both can see through walls.
  • Used in Soldier of Fortune: Double Helix. The infrared goggles allow you to see people and dogs (and nothing else) in range as bright red silhouettes, even through walls.
  • Averted in the Splinter Cell series, as you can't see through walls or objects with infrared — even enough air provides an opaque obstacle, as its lower temperature masks the heat from the target. However, in one mission in Chaos Theory, you can see through thin paper walls (thin as in "reach through and grab somebody" thin). The thermal signature is really faint, so it may very well be plausible. Oddly, compared to the realism of most of the series, glass is thermally transparent — unless, of course, there's a light shining through it.
  • The Steyr AUG in Syphon Filter: The Omega Strain has a false-color infrared scope with this effect. Same for the infrared goggles in Dark Mirror.

  • In Jupiter-Men, one of Arrio's spells, "Ojo de Fuego" (Eye of Fire), lets him see the infrared spectrum to locate others through their heat signatures. This also lets him see through walls to see the silhouettes of people behind them.

    Web Original 
  • In Curveball, Street Ronin has a set of these built in to his visor. At one point it's implied that the enemy has them as well, as Street Ronin watches them redeploy on the roof in response to his own movements.

    Western Animation 

    Real Life 
  • An actual "X-ray camera" does in fact exist. Although it uses terahertz microwaves rather than infrared or X-ray to function, and has more in common with radar than anything else, it can still see through walls and clothing, but not metal.
    • Terahertz waves have wavelengths of a few tenths of a millimeter and can see through non-metallic materials up to a few millimeters thick. To see through thick walls requires centimeter wavelengths; at which point one is using something between a radar and a wifi transmitter.
  • The KGB developed an X-Ray that could show the lock of a safe while it was being cracked; its drawback was the high levels of radiation produced. It was joked in the KGB that you could tell a veteran safecracker by their lack of teeth.
  • Astronomers have of course used cameras of various wavelengths for some time. Generally more useful for looking at stellar objects rather than through walls, mind you.
    • Also an example of some of the problems with infrared: astronomy at infrared frequencies languished for decades until satellites could carry telescopes and new observatories were built on high mountaintops because the infrared light could not penetrate far through air.
    • That's why there're X-ray telescopes mounted in satellites orbiting the Earth (like Chandra); X-rays coming from celestial bodies cannot penetrate Earth's atmosphere.
  • Some materials are transparent to infrared, but opaque to the visible spectrum, so this trope is in play some of the time. Potassium bromide is one of those things. Many chemists and students have taken infrared spectra of reaction products by grinding up those products in a mortar with some potassium bromide, pressing that mixture into a wafer, and projecting infrared light through that wafer.
  • Thermal imaging cameras make use of long-wave infrared to detect the temperature of objects, which often allows the user to see things hidden to the naked eye. In fact, FLIR (the world's largest thermal camera maker) calls thermal imaging "the world's sixth sense." However, they are very expensive due to high demand and low supply.
  • Pit vipers have a biological version of this. Their name comes from small pits in their heads that let them sense infrared. While they can't see through objects, this sense allows them to hunt prey and avoid predators at night.
  • Some Sony cameras feature "Nightshot" modes, that allow to take images in absolute darkness using infrared wavelengths. It's more of a gimmick, though.