New Frontiers of Color: Non-Spectral Colors

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What is the color of infrared? Is it red, or is that what the camera makes us see? Can infrared show another color then? What AIST (Advanced Industrial Science and Technology), Japan’s largest research organization, has realized is that infrared can act just like the light we see. Since it has different wavelengths and can reflect and refract, it can be used as a substitute for visible light!

Infrared Vision

If you have seen the average action movie, or played a stealth game before, then you probably know about night vision. Night-vision goggles have existed since World War II, and have since gone through many improvements.

It is because infrared is not seen by the naked eye, but detectable through other sensors, which then transform an infrared image to a visible one, that the first version of night vision goggles contained infrared emitters. Surveillance cameras too are aided with infrared lamps to get a high-resolution, monochromatic picture of the place they are monitoring at night.

According to the Black-body Radiation Law, any object that has a temperature above the absolute zero emits infrared. Thermography, which is superior in that it does not need to use any artificial emitters, utilizes the differences in temperature between these objects, such as a hot human behind a passive wall, and the relationship between that and the type and intensity of infrared emitted by each object to identify targets. This type of vision can work during daytime as well.

All these technologies have been developed many years ago, and are well-known to many; so what is new?

Night-Vision in Cars

In 2000, General Motors equipped the Cadillac Deville with a night vision system. Typical non-infrared night vision systems use an image intensifier, which gives you great detail on objects that have a tiny amount of light shining on them.

The problem with implementing that in cars is that a streetlamp or the headlights of a car coming the opposite way will lead to an effect known as “whiteout”. The light would be so strong in its amplified state that it will cover up the screen showing almost nothing but it.

The solution was to use thermography; instead of relying on already available light and amplifying it, thermal vision relies solely on the temperatures of the objects being filmed, and the amount of infrared they consequently produce. This gives a more consistent image regardless of the amount of illumination available at the scene. The image provided is, as expected, black and white; it is shown on a Heads-Up Display (HUD), which is a screen on the lower part of the windshield.

The technology has not stopped at that; in 2004, Honda added pedestrian detection. What it calls the “Intelligent Night Vision System” uses infrared cameras to not only show a decent black-and-white image in the dark, but also has a computer system that identifies pedestrians, surrounding the image of one in your way or about to become in your way with a box and making an alarming noise to prevent accidents.

Adding Color

Color is a blessing that we take for granted. It is not until you meet a color-blind person or watch a movie such as “Pleasantville” that you realize how important colors are to us. How else can you understand a color-coded map? Would doctors be able to treat wounds if they do not know their color? What if you are diffusing a bomb and do not know which wire is the red one?

Color is everywhere, and it is crucial to life. The people at Tenebraex, a Boston company, have realized that and, by 2007, they had invented color night-vision goggles. Through a complex mechanical system based on filters, a user of these goggles can now see in full color at night, in illumination as low as quarter-moon nights. In addition to the goggles, they have also developed software for color-blind people to help them identify colors they cannot see.

It did not stop at that however; in 2011, AIST invented color infrared-vision cameras. Infrared was always conceived as monochrome, but with a complex computer algorithm that analyzes patterns in the reflection of infrared from objects into three color components—Red, Green and Blue—they were able to produce a full color image at night. The camera relies solely on the infrared emitted from or reflected by objects; it needs no additional light source. The different intensities of the three colors analyzed are combined to obtain a pixel’s real color, in a system widely known as RGB.

So as you can see, color is not confined to what the visible spectrum of light shows us. There are numerous ways in which electromagnetic waves can be used to let us see so much more than we can see through visible light, and now, we can see all this in color.

References

vxm.com
world.honda.com
gizmodo.com
engadget.com
camouflage.com
zdnet.com
colormatters.com

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