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What is Automotive Night Vision?

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automotive night vision hud

Some cars have a night vision image on a heads up display.

Photo © Steve Jurvetson

The term “automotive night vision” refers to a number of systems that help increase driver awareness when it’s dark out. These systems extend the perception of the driver beyond the limited reach of the headlights through the use of thermographic cameras, infrared lights, heads up displays, and other technologies. Since automotive night vision can alert drivers to the presence of potential hazards before they become visible, these systems can help prevent accidents.

How Does Night Vision Work in Cars?

Automotive night vision systems are broken into two basic categories, which are referred to as active and passive. Active night vision systems uses infrared light sources to illuminate the darkness, and passive systems rely on the thermal radiation that is emitted from cars, animals, and other potential hazards. The systems both rely on infrared data, but each one has its own benefits and drawbacks.

Active Automotive Night Vision Systems

Active systems are more complex than passive systems because they use infrared light sources. Since the infrared band falls outside the visible spectrum, these light sources don’t cause oncoming drivers to suffer from temporary night blindness like high beam headlights can. That allows the infrared lights to illuminate objects that are significantly further away than headlights are able to reach.

Since infrared light isn’t visible to the human eye, active night vision systems use special cameras to relay the extra visual data. Some systems use pulsed infrared lights, and others use a constant light source. These systems don’t work very well in adverse weather conditions, but they do provide high contrast images of vehicles, animals, and even inanimate objects.

Passive Automotive Night Vision Systems

Passive systems don’t use their own light sources, so they rely on thermographic cameras to detect thermal radiation. This tends to work very well with animals and other vehicles since they emit a lot of thermal radiation. However, passive systems have trouble picking up inanimate objects that are about the same temperature as the surrounding environment.

The range of passive night vision tends to be significantly higher than the range of active night vision, which is due to the limited power of the light sources used by the latter systems. The image quality produced by the thermographic cameras also tends to be poor when compared to active systems, and they don’t work very well in warm weather.

How Does Infrared or Thermographic Information Help Me See?

There are a number of types of night vision displays that can relay infrared or thermographic information to the driver. The earliest night vision systems used heads up displays, which projected warnings and alerts on the windshield within the driver’s field of vision. Other systems use an LCD that's mounted on the dash, in the instrument cluster, or integrated into the head unit.

What Vehicles Have Night Vision Systems?

Automotive night vision systems have been around since 1988, but they are still found primarily in luxury vehicles. The technology is typically optional equipment, and it can be quite expensive. The first night vision systems were introduced by GM, but a number of other automakers now have their own versions of the technology.

Mercedes, Toyota, and Toyota’s Lexus badge all offer active systems. Other automakers, such as Audi, BMW and Honda, offer passive options. General Motor's Cadillac badge also offered a passive night vision system, but the option was discontinued in 2004.

There are also a number of systems available in the aftermarket.

Does Night Vision Really Help Reduce Accidents?

According to the European Commission for the Automobile Industry, nearly 50 percent of all accidents occur at night. Since the same study showed about 60 percent less traffic at night, it’s clear that a disproportionate number of accidents occur between dusk and dawn. Since night vision isn’t widely available, there is no conclusive data. A study performed by the National Highway Transportation Safety Administration even revealed that some people are willing to drive faster at night with the aid of these systems, which could lead to more accidents.

However, other technologies that increase nighttime visibility have been shown to reduce accidents. Since technologies like adaptive headlights have helped reduce nighttime accidents, it’s possible that a wider adoption of night vision could have similar effects.

Night vision systems can detect objects that are more than 500 feet away, but traditional headlights typically only illuminate objects that are about 180 feet away. Since the stopping distance of a car can easily be longer than 180 feet, it’s clear that the proper use of a night vision system can help an alert driver avoid certain collisions.

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