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A Short Introduction to Automotive Lidar Technology

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Re: A Short Introduction to Automotive Lidar Technology

#91

Post by Animats »

JayPalm wrote: post #85
Animats wrote: post #8

That's a reasonable basic overview. I'm surprised that rotating scanners are still used. It's been twenty years since Velodyne built their first one. They work OK, but cost too much. I was expecting flash LIDAR or MEMS mirrors to take over. Continental, the auto parts company, bought the leading flash LIDAR company over a decade ago, but the volume market a big parts company needs never appeared. Waymo is still using…

Continental is folding their automotive LiDAR division and is laying off everybody.

Not surprised. I don't think they sold many.

Re: A Short Introduction to Automotive Lidar Technology

#93

Post by Animats »

aftbit wrote: post #19
xnx wrote: post #10

Earlier quoted context omitted.

> They work OK, but cost too much. Costs have dropped dramatically in the past 20 years and continue to do so. > There needs to be a cheap, flush-mounted replacement for those things. Why? Corners are the optimal mounting position for maximum visibility. It allows the car to -in-effect- see around corners in ways no centrally mounted sensor can. > Waymo needs to solve that problem before they do New York. What? Becau…

Have you ever seen the corners of a car that has been parked in a big East-coast city? They will sustain damage during the course of normal operation and storage, and many people will not stop and leave their insurance information, especially if the damage is perceived as minor and happens while the car is parked and the owner not present. Currently, the corners of a car are relatively non-critical to its function an…

Right. It seems to have been Waymo's decision to have zero blind spots around the vehicle perimeter, even if that means having the sensors stick out.

Cruise had an accident where another vehicle knocked a pedestrian into a Cruise car, and the pedestrian was dragged. Cruise lost their California DMV autonomous license for that. So there's a good case for full perimeter coverage.

Humans don't have that. The same week as the Cruise incident, a NYPD tow truck dragged a pedestrian some distance because they were in a blind spot for the driver.

Re: A Short Introduction to Automotive Lidar Technology

#94

Post by maxbond »

fragmede wrote: post #37
itishappy wrote: post #31

Earlier quoted context omitted.

Time of flight ranging is used in nature by bats and whales/dolphins.

and humans! https://www.atlasobscura.com/articles/how-to-echolocate

My back of the napkin estimate is that a human using time of flight ranging would be unable to distinguish between an object directly in front of their face and 8.6 meters away[1]. I think human echolocation uses a different mechanism (presumably relating to amplitude)?

Skimming the Wikipedia article[2], it seems like animals do use time of flight, but also Doppler shifting.

(As a side note, some animals have apparently evolved active countermeasures to echolocation!? It seems obvious in retrospect but incredibly cool.)

There's interesting research into the mechanisms of human echolocation [3], but it was over my head. My impression was that the jury is out as far as the precise mechanisms involved but that there's a lot of evidence to be considered, I'm sure someone with a better background would get more out of it than I did.

(I'm just curious about the mechanism, I agree that LIDAR has natural analogs.)

[1] Speed of sound * 25ms, 25ms being the rule of thumb I've memorized for the minimum interval for two sounds to register as distinct from each other. This is just folk wisdom I've picked up hacking on audio, so perhaps I'm mistaken.

[2] https://en.wikipedia.org/wiki/Animal_echolocation

[3] https://durham-repository.worktribe.com/preview/1375913/1963...

Re: A Short Introduction to Automotive Lidar Technology

#95

Post by Filligree »

Animats wrote: post #93
aftbit wrote: post #19

Earlier quoted context omitted.

Have you ever seen the corners of a car that has been parked in a big East-coast city? They will sustain damage during the course of normal operation and storage, and many people will not stop and leave their insurance information, especially if the damage is perceived as minor and happens while the car is parked and the owner not present. Currently, the corners of a car are relatively non-critical to its function an…

Right. It seems to have been Waymo's decision to have zero blind spots around the vehicle perimeter, even if that means having the sensors stick out. Cruise had an accident where another vehicle knocked a pedestrian into a Cruise car, and the pedestrian was dragged. Cruise lost their California DMV autonomous license for that. So there's a good case for full perimeter coverage. Humans don't have that. The same week a…

Did the tow truck driver lose their license?

Re: A Short Introduction to Automotive Lidar Technology

#96

Post by rightbyte »

itishappy wrote: post #27
0_____0 wrote: post #22

Earlier quoted context omitted.

IIRC the data coming out of the Conti radars was preprocessed to give bearing, distance, and size of an object in the FOV of the unit. I don't know if I ever saw the true raw data out of one of them, but I'm curious what it looks like.

I'd be curious if the design of the Cybertruck affects readings at all. It's got angles straight outta an F-117.

I think "stealth" planes assumes the radar is under the plane on the ground? For the geometry. And they have some color or alloy that reflect less.

Re: A Short Introduction to Automotive Lidar Technology

#97

Post by tgaj »

fragmede wrote: post #86
fragmede wrote: post #29

Earlier quoted context omitted.

If we want the sell driving computer to be only possibly as good as a human. I can't see in the dark, can't see through fog, and have trouble with rain. Why is human visibility the bar to meet here?

Oh and the sun. I get blinded when the sun is in my eyes at sunrise and sunset.

And how many car accidents did you cause in your life? Probably still no a lot even with your flawed vision.

Re: A Short Introduction to Automotive Lidar Technology

#98

Post by tgaj »

ra7 wrote: post #64
xdmr wrote: post #54

Earlier quoted context omitted.

Is that because their vision fails to provide the information necessary to drive safely? Or is it due to distraction and/or poor judgment? I don't actually know the answer to this, but I assume distraction/judgment is a bigger factor. I'm not a fan of the camera-only approach and think Tesla is making a mistake backing it due to path-dependence, but when we're _only_ talking about this is _broadly theoretical_ terms,…

> Is that because their vision fails to provide the information necessary to drive safely? In certain conditions, yes. Humans drive terribly in dark and low light, something lidar excels in.

Still, millions of humans drive every night and only a miniscule percentage cause any accidents. So maybe we are not so bad at this.

Re: A Short Introduction to Automotive Lidar Technology

#99

Post by tgaj »

carbotaniuman wrote: post #60
tgaj wrote: post #24

Earlier quoted context omitted.

Theoretically if a human can drive a car using a pair of eyes connected to brain, it should be possible to do that using two cameras connected to some kind of image processing unit.

Theory isn't really all that applicable to this though - in theory nothing is stopping anyone from writing all code in assembly, but obviously that doesn't happen. I think more practically cars have adding driver assistance feature for a while now - more cameras, blind spot monitoring, ultrasound for parking, lane drift indicators. It is therefore not unreasonable to assume that adding more sensors is helpful (but ev…

To be honest, it's possible that having too much data can only cause problems in quick decision-making. Any redundant data will only slow down processing pipelines.

Re: A Short Introduction to Automotive Lidar Technology

#100

Post by tgaj »

xdmr wrote: post #54
knifie_spoonie wrote: post #36

Earlier quoted context omitted.

In practice humans aren't particularly safe drivers.

Is that because their vision fails to provide the information necessary to drive safely? Or is it due to distraction and/or poor judgment? I don't actually know the answer to this, but I assume distraction/judgment is a bigger factor. I'm not a fan of the camera-only approach and think Tesla is making a mistake backing it due to path-dependence, but when we're _only_ talking about this is _broadly theoretical_ terms,…

I totally agree, I think most accidents are caused by human nature (especially slow reaction time in specific conditions like being tired or drunk) and ignoring laws of physics (driving too fast). And some are just a pure bad luck (something/someone getting on the road right in front of the car).
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