The generic term » car night vision» refers to a number of loosely coupled technologies that can help raise awareness of situations where it is difficult to see the road in low light conditions.
These systems use thermographic cameras, infrared lamps and displays for head, to expand the driver’s perception beyond the limited range of the headlights. By alerting drivers to invisible hazards, car night vision can help prevent accidents.
What is car night vision for cars?
Uses thermographic cameras to detect thermal radiation.
Great for identifying vehicles, animals, people and other «thermal» objects.
Uses infrared light to illuminate darkness.
Shows objects that are much farther away than the headlights can see.
There are two categories of car night vision: passive and active. Passive systems use thermal imaging cameras that illuminate the heat emitted by objects, animals, and people. Active systems use infrared light sources to illuminate the darkness.
Both active and passive night vision systems rely on a spectrum of infrared light that is invisible to the naked eye. Each of them has its own advantages and disadvantages.
Passive night vision pros and cons
Shows people, animals and other vehicles well.
The visibility range is higher than that of active night vision.
Not very good at detecting inanimate objects such as rocks or barriers.
Less effective in warm weather.
Passive night vision systems rely on thermographic cameras to detect thermal radiation. Since thermographic cameras can «see» heat, it is easy for them to pick out the difference between a warm object, like a person, and a cooler object like a road.
Data from the thermal cameras used in passive systems is processed into a black and white image that provides the driver with an enhanced view of the road. Due to the reliance on heat emissions, passive systems tend to work very well with people, animals, and other vehicles, since they all emit a lot of thermal radiation. The drawback of passive systems is that they have trouble picking up inanimate objects that are roughly the same temperature as the surrounding environment.
The range of passive night vision tends to be higher than the range of active night vision. This is due to the limited power of the light sources used by active systems. However, the image quality produced by the thermographic cameras tends to be poor when compared to active systems. They also don’t work as well in warm weather since an increase in the ambient temperature will naturally cause normally cool objects, like road surfaces, to warm up during the day and then radiate heat after the sun goes down.
Active Night Vision Pros and Cons
Image quality generally better than passive night vision.
Can illuminate objects that are farther away than headlights can reach.
Does not work well in poor weather conditions, like snow and hail.
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 often do. This allows the infrared lights to illuminate objects that are much farther 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, like heavy snow or hail, as it can partially block the infrared light source. However, active systems can provide high contrast images of vehicles, animals, and even inanimate objects.
How Does Infrared or Thermographic Information Help You See?
There are different ways for night vision displays to 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 mounted on the dash, instrument cluster, or head unit.
Which 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 usually optional and 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, including 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 aftermarket systems available.