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Night Vision Systems

Basic Description

Night vision systems use infrared image sensors to detect and produce images of objects that are difficult to see in the absence of sufficient visible light. There are two main categories of automotive night vision systems, active and passive. Active night vision systems use infrared light to illuminate dark surroundings, while passive systems rely on thermal radiation emitted by humans, animals and other objects at a temperature different from the ambient.

Active night vision systems operate at infrared wavelengths near the visible spectrum (0.7 - 3.0 μm). These systems have their own infrared light source that illuminates the objects at a significant distance ahead on the road where the headlights cannot reach. The reflected infrared light is captured by infrared cameras. Light is emitted by these systems in two forms, gated and non-gated. Gated systems emit pulses of infrared light while non-gated systems emit constant infrared light. Active night vision systems provide clear monochromatic images of the road ahead and its surroundings.

Passive night vision systems operate at longer infrared wavelengths than active systems (8 - 12 μm). They detect the thermal radiation emitted by humans and animals using thermographic cameras. They are not capable of detecting obstacles at the ambient atmospheric temperature. Passive systems can generally detect objects at longer distances compared to active systems and are better at seeing through fog.

Automotive Night Vision Demonstration: Clemson AuE835 Class Project by Fan Zeng

Sensors
Infrared image sensor
Actuators
Image display, infrared lights (active systems), headlights, warning chime or tone
Data Communications
Typically, closed-circuit systems that do not use standard automotive data communications networks, but may use CAN or LIN to interface with headlights.
Manufacturers
Autoliv, Bosch, BrightWay Vision, Continental, Flir, Protruly
For More Information
[1] How In-Dash Night-Vision Systems Work, Josh Briggs, How Stuff Works, Jan. 26, 2009.
[2] Mercedes-Benz S-Class Night View Assist Night Vision Video, YouTube, July 16, 2009.
[3] Audi Night Vision Assistant - How does it work?, YouTube, Oct. 24, 2011.
[4] Bosch Night Vision - Night Vision Plus, YouTube, Mar. 22, 2011.
[5] Night-Vision Systems Compared from BMW, Mercedes, and Audi - Car and Driver, YouTube, June 14, 2012.
[6] Night Vision with Dynamic Light Spot and Animal Detection - BMW Group, YouTube, Sep. 16, 2013.
[7] FLIR Night Vision System EXCLUSIVE - Fast Lane Daily, YouTube, Sep. 24, 2014.
[8] Driving a BMW with night vision proves illuminating, Consumer Reports, Oct. 2014.
[9] Consumer Reports: Night-Vision Car Technology, WFMY News, Jan. 16, 2015.