Night Vision System
Even with properly adjusted headlights, pedestrians, cyclists, and animals on the road ahead can be difficult to detect in the dark. And, the problem is worse if it's raining or if there is glare from the headlights of oncoming vehicles.
Night vision systems use the same technology employed by the military in nightime combat situations, and by search and rescue personnel working at night, to let vehicle drivers "see in the dark" and identify potential hazards on the road ahead.
How do they work?
Night vision systems use video cameras that are sensitive to infra red to detect the heat given off by humans and animals against the colder background of the roadway environment. Infra-red emitters may also form part of the vehicle's headlights to help detect objects at greater distances than is possible using only the naked eye with conventional lighting.
An in-vehicle display mounted in the instrument panel, or a head-up projection system showing the image on the windshield in the driver's direct field of view, shows the road ahead as a grey-scale image.
Potential hazards, such as pedestrians walking along the edge of the road, or animals crossing the road directly in the vehicle's path, show up as bright objects against a darker background.
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Are there any risks?
Drivers must be aware that night vision systems are secondary to their direct view of the road ahead. In the dark, high beam headlights should be used where practicable to provide the greatest possible range of illumination.
In urban locations, the presence of street lighting and illuminated commercial signs can reduce the contrast between target objects and the surroundings making interpretation of the night vision display more difficult.
There is potential for the night vision display to be a distraction, especially when the technology is initially being used. Drivers must make a conscious effort to focus on the regular driving tasks, especially scanning the road ahead, and only take only occasional glances at the night vision display to assimilate the additional information that this can provide.
What can science tell us?
Automotive night vision system; Nancy S. Martinelli and Richard Seoane; Proc. SPIE; Vol. 3700; April, 1999
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While only about one-quarter of vehicle miles are driven at night, over half of vehicle related fatalities occur in the hours of darkness. Having the goal of improving nighttime driving safety, Cadillac along with Raytheon Systems Company and Delphi-Delco Electronics have developed a night vision system consisting of a passive infrared sensor, a head-up display, and display controls.
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Night vision enhancement systems: What should they do and what more do we need to know?; Kåre Rumar; The University of Michigan
Transportation Research Institute; Report No. UMTRI-2002-12; June, 2002
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This report outlines the two main types of night vision enhancement systems. Active or near infrared (NIR) systems require an infra red source but give a complete picture of the scene in front of the driver. Passive or far infrared (FIR) systems do not need an infra red source but only enhance relatively warm objects (such as people and animals). There are three main display alternatives: a contact analog display with the
camera view superimposed on the direct view of the road by means of a head-up display (HUD), a separate HUD on the top of the dashboard, and a head-down display (HDD) in the dashboard. The report analyses what a NVES should do to improve night visibility, highlights potential problems, and discusses issues requiring future research.
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Useful links
Night Vision System (Autoliv)
Night Vision System for Cars (Siemens)
See through the darkness (BMW)
Cadillac Night Vision System (Marlow Industries)
Next Generation Thermal Infrared Night Vision System
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Quick Facts
- An infra-red camera detects the heat from pedestrians, cyclists and animals
- A detected object shows as a white image against the dark background of the roadway environment
- A night vision system is a secondary aid to the driver's direct view of the road
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