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Comment by UI_at_80x24 | Hacker News Reader

Jumping on the 'agree' bandwagon. >The long term safer option will be to use both types of sensors before together

This 100% is the real target but I'd like to add to it.

Camera-based systems rely on ambient photons arranged in a pre-determinded configuration hitting a sensor. Lidar-based systems rely on reflected photons hitting a sensor.

What I would prefer to see is a LiDAR/RADAR combination. When both systems rely on "photons" you suffer the same inherited weaknesses of both. i.e. fog

But split it up and you can be SAFER.

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>What I would prefer to see is a LiDAR/RADAR combination. When both systems rely on "photons" you suffer the same inherited weaknesses of both. i.e. fog

Fog isn't the only problem with relying on ambient photos. "Nighttime" is a really big problem here.

I really don't get this idea that optical sensors and processing are the solution for autonomous navigation. I propose this simple test for the pro-camera people: get in your car at 1AM, drive to a very rural place with a windy road, then turn off your headlights, and try driving on that road at 55mph. If you survive, come back and tell us how safe you think that exercise was.

LiDAR doesn't have this problem, because it generates its own light source (a laser), and doesn't need overly-bright headlights to turn darkness into daytime, with all the problems that's now causing (light pollution, vision problems in people who drive at night from all the glare, etc.).

Why are we turning off our headlights in this exercise?

To illustrate the problems with optical sensors. What happens when the headlights fail, or if one of them fails, or if a bunch of snow or ice builds up in front of them?

I also addressed some of the problems with relying on headlights at the end of my comment: to get better visibility, you need more light. This doesn't come without costs to the environment and to other drivers (like those who don't have driverless cars yet); in fact, too-bright lights are making it unsafe to drive at night now.

As an aside, I think it should be illegal for anyone to have a car with non-halogen headlights without automatic high-beam dimming. Xenon and LED lights are great for illuminating dark roadways, but they're horrible when they on the car coming towards you, and that driver is too stupid or careless to dim their high beams. Temporary blindness is the result of this.

> What happens when the headlights fail, or if one of them fails, or if a bunch of snow or ice builds up in front of them?

What's expected of a normal driver when the headlights fail? Turning on the hazard blinkers, slowing down carefully, and finding their way to the shoulder?

There's also a reason there are two headlights.

Ah yes, I can't wait for my future where my car refuses to drive me because one of the headlight sensors shows it's failed when it's working fine and the other is fine.

If the cameras only see darkness, which would be a giveaway that the headlights are not working, I would prefer the car not drive itself

Correct, the visibility is the thing you'd want to look out for because it applies to a wide range of issues, including a camera with a blocked lens (either intentionally or by something like a wet leaf).

This is pedantic, but RADAR relies on photons as well - radio waves are just a different frequency of EM radiation vs visible light. A RADAR system emits photons that are reflected and hit a sensor like LIDAR does (or like a camera with a flash does). I think your point that having more diverse sensors is safer stands though.

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