Case Study: Technology

What is an Infrared Camera?

A thermographic or 'infrared' camera forms an image using infrared radiation. Infrared theory states that all objects emit a certain amount of radiation based on their temperature, called black-body radiation. In most cases, the higher the object's temperature, the more infrared radiation is emitted.

An infrared camera detects this radiation the way an ordinary camera detects and processes visible light. It works even in total darkness because the overall light level does not matter. Images from infrared cameras tend to be monochromatic because the cameras are generally designed with only a single type of sensor responding to single wavelength range of infrared radiation.

Infrared cameras can generally be divided into two types of cameras: those with cooled infrared image detectors and those with uncooled infrared image detectors.

Cooled Image Detectors are typically contained in a vacuum-sealed case and cryogenically cooled. Their sensitivity is increased because their own temperatures are much lower than the objects from which they are trying to detect radiation. Their sensors would be 'blinded' or flooded by their own radiation if they were not cooled.

Because of these 'cool' properties, they can provide superior image quality than uncooled infrared cameras. The drawbacks are that they are expensive to run and produce, using a lot of time and energy.

There are many models out there ranging from the most basic to more deluxe models, and the technology keeps getting better. Because of infrared technology, a firefighter could go into a burning building and rescue people, target hot spots, and see through the smoke. The range of uses for infrared technology keeps growing, and infrared cameras can now be used by a company or organization, and even an individual's home.

Uncooled infrared cameras are different than their cooler cousins because their sensors operate at room temperature. The sensors detect infrared radiation via an electrical signal that is sent back to them when they detect higher temperatures. Uncooled infrared cameras are smaller and less costly than cooled infrared cameras but their resolution and image quality tend to be lower. Uncooled infrared cameras can get noisier as they get hotter, but they can also stabilize to an operating temperature that reduces image noise

A concept that revolutionized camera technology, infrared cameras opened numerous new doors for security and intelligence operations. Once existing solely in the realm of science fiction, infrared technology has now become a standard facet of our everyday lives.

Uses

Infrared cameras have many practical uses. The most common application for the average user is security purposes. Because many night vision cameras are approved for outdoor use, they are ideal for allowing property owners to monitor their premises without adding another external lighting source.

a night vision camera with 104 LEDs

That’s not to say that infrared cameras do not emit light themselves. The size of the LED (light emitting diode) determines how visible the light is. Common sizes are 850nm and 940nm. The 940nm LEDs do not emit as much light and as a result, cameras equipped with them usually have more LEDs attached than their 850nm counterparts. In most applications, those being monitored would have to know where the camera is in order to see the light emitted from the LEDs.

Infrared cameras also have industrial uses. Firefighters often use them to “see” through smoke in order to locate people. An infrared camera can also be used by electricians to see if certain electrical systems are overheating, which is dangerous. And exterminators can use infrared camera to detect termites or other pests.

an infrared image of a dog with pseudo colour

Because night vision cameras emit minimal light, they are ideal for monitoring people or animals without interrupting their sleep. This is why infrared cameras are often used to monitor participants involved in sleep studies. The average user could monitor their sleeping babies or children much the same way. It is also possible to monitor nocturnal pets or other animals without disturbing them with much light.


More about infrared cameras here, the Wikipedia page.




Kinect : How Does It Work

Camera

Kinect’s camera is powered by both hardware and software. And it does two things: generate a three-dimensional (moving) image of the objects in its field of view, and recognize (moving) human beings among those objects.

Older software programs used differences in color and texture to distinguish objects from their backgrounds. The camera transmits invisible near-infrared light and measures its “time of flight” after it reflects off the objects.

Time-of-flight works like sonar: If you know how long the light takes to return, you know how far away an object is. Cast a big field, with lots of pings going back and forth at the speed of light, and you can know how far away a lot of objects are.

Using an infrared generator also partially solves the problem of ambient light. Since the sensor isn’t designed to register visible light, it doesn’t get quite as many false positives.

Kinect goes one step further and encode information in the near-IR light. As that information is returned, some of it is deformed — which in turn can help generate a finer image of those objects’ 3-D texture, not just their depth.

With this tech, Kinect can distinguish objects’ depth within 1 centimeter and their height and width within 3 mm.

 

Middleware

At this point, both the Kinect’s hardware — its camera and IR-light projector — and its firmware (sometimes called “middleware”) are operating. The Kinect has an on-board processor which is using algorithms to process the data to render the three-dimensional image.

The middleware also can recognize people: distinguishing human body parts, joints and movements, as well as distinguishing individual human faces from one another. When you step in front of it, the camera “knows” who you are.

Does it “know” you in the sense of embodied neurons firing, or the way your mother knows your personality or your confessor knows your soul? Of course not. It’s a videogame.

But it’s a pretty remarkable videogame. You can’t quite get the fine detail of a table tennis slice, but the first iteration of the WiiMote couldn’t get that either. And all the jury-rigged foot pads and nunchuks strapped to thighs can’t capture whole-body running or dancing like Kinect can.

That’s where the Xbox’s processor comes in: translating the movements captured by the Kinect camera into meaningful on-screen events. These are context-specific. If a river-rafting game requires jumping and leaning, it’s going to look for jumping and leaning. If navigating a Netflix “Watch Instantly” menu requires horizontal and vertical hand-waving, that’s what will register on the screen.

It has an easier time recognizing some gestures and postures than others. As Kotaku noted this summer, recognizing human movement — at least, any movement more subtle than a hand-wave — is easier to do when someone is standing up (with all of their joints articulated) than sitting down.

So you can move your arms to navigate menus, watch TV and movies, or browse the internet.

Audio

Kinect also has a stereo microphone to enable chat and voice commands. The tech on the audio capture is fairly well-known, but it’s worth observing that unlike the noise-canceling microphone you might have on your smartphone or laptop’s webcam, Kinect has a wide-field, conic audio capture.

This is because, unlike a smartphone, you wouldn’t want the Kinect’s microphone to capture only sounds close to it: It’d only pick up the sound of the television set. You want it to capture ambient speech throughout the room, such as that emitted by whole groups of people watching sports or playing games.

A traditional videogame controller is individual and serial: It’s me and whatever I’m controlling on the screen versus you and what you’re controlling. We might play cooperatively, but we’re basically discrete entities isolated from one another, manipulating objects in our hands.

A videogame controller is also a highly specialized device. It might do light work as a remote control, but the buttons, d-pads, joysticks, accelerometers, gyroscopes, haptic feedback mechanisms and interface with the console are all designed to communicate very specific kinds of information.

Kinect is something different. It’s communal, continuous and general: a Natural User Interface (or NUI) for multimedia, rather than a GUI for gaming.

Kinect's Wikipedia page.