What is thermal driving night vision, how does it work, and do I really need it in my next car?


Car thermal driving night vision, now that it can reliably detect and alert you to pedestrians, cyclists and deer beyond the reach of your headlamps, is well worth considering when you’re looking to buy your next car. The newest and best systems employ algorithms that determine whether an infrared hot spot is a living, moving thing near the roadway, then swivels a headlamp element to alert the driver — and the person or animal.

How passive thermal driving night vision works: long range, simpler image

Thermal driving night vision systems use an infrared sensor typically in the grille to look for warm objects in the roadway. The sensor is a video camera that captures the infrared spectrum just above visible light. The sensor outputs the moving image to a dashboard display. Increasingly, that’s coupled with sophisticated algorithms that detect humans and large animals, and most recently, that sound an alert. This is the case for all thermal driving night vision technologies.

The majority are passive thermal driving night vision systems. Think of passive meaning efficient, not weak or submissive. They measure the heat generated by living objects without the need for additional illumination. Warmer objects show up as lighter images on the car’s LCD, colder objects show up as dark. In between dark grays are the road and rocks emitting heat from the sun into the evening hours.

Passive thermal driving night vision wins hands down for claimed range, up to 1,000 feet or 300 meters. (At 60 mph on a country road, that’s theoretically more than 10 seconds of travel time.) Passive systems work better in rainy and foggy conditions. The majority of cars use passive sensors, including Audi and BMW. On the downside, passive systems work less effectively at warmer temperatures. They sense polar bears against snow better than camels against sand. BMW for instance says the upper range for effectiveness is 98F (35C). They’re also mounted low in the grille or under the bumper, so much so that when you pull up to a traffic light, you’re almost looking up to the level of the exhaust system on the car ahead. Lugers would appreciate the view.

How active thermal driving night vision works: shorter range, lifelike images

Active thermal driving night vision systems use an infrared illuminator, sometimes part of the headlamp cluster, to light up the road in the IR spectrum. The image can be higher-resolution than passive. Roads and buildings show up better. That’s why drivers initially think they’re watching black and white TV of the road ahead.

With active thermal driving night vision, it’s possible to mount the camera higher in the car, in the rear view mirror cluster, for a better view. As with normal headlamps, the range of active thermal driving night vision systems is reduced in rain, snow or fog, and effectiveness falls off with the square of the distance. The lifelike image might induce some drivers to think they can steer by the thermal driving night vision display alone; it’s just not possible except maybe for a few seconds on country roads where the illuminator clearly shows the pavement centerline and edge markings.

How it works on the road: Auto detection and alerting makes all the difference

I’ve driven night vision cars off and on since the early 2000s, including the first in the US, the Cadillac DeVille and then the Hummer. Every one impressed me at the time, in the sense of a dancing bear: You’re so impressed the bear is “dancing” that you ignore the question of how well. About five years ago, thermal driving night vision got better with pedestrian then animal detection, where a light-colored rectangle outlines the hazard. That evolved to actually colorizing the moving objects, typically yellow for humans, orange for animals.

The real advance is the proactive warning, an audible alert and a warning icon in the instrument cluster, or even better in the head-up display. Several times on back roads of Cape Cod and rural New York State in thermal driving night vision-equipped BMWs, the alert sounded before I saw a person or moving animal. I reduced speed, tried to peer farther ahead down the road, and eventually made out the object, most of the time. A couple times after the alert, I never saw the person or animal, and I couldn’t tell if it was a false positive or if the object had moved outside the warning zone by the time it could be picked up on headlamps.

This article comes from extremetech edit released

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