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A Short Introduction to Automotive Lidar Technology

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Re: A Short Introduction to Automotive Lidar Technology

#141

Post by flutas »

KaiserPro wrote: post #129
sroussey wrote: post #48

Earlier quoted context omitted.

I know we are talking about car type lidar, but the iPhone Pro has a type of one and gets a depth map of photos. So you’re shooting it everyone you are taking photos of.

I don't think the Lidar in apple's stuff is actually a lidar, I think its a structured light sensor.[1] What do I mean by that? lidar sends pulses of light and works out the difference between emission time and arrival time to work out how far the pulse has travelled. The structured light sensor emits a pattern or dots, and any distortion of that can be used to compute the shape of an object. [1] https://image-ppubs.…

They aren't talking about FaceID.

iPhone 12 introduced a lidar sensor in the back.

https://www.nature.com/articles/s41598-021-01763-9

Re: A Short Introduction to Automotive Lidar Technology

#142

Post by Symmetry »

hammock wrote: post #131
deepnotderp wrote: post #52

Earlier quoted context omitted.

No, there’s a class system for laser safety The rating is for you to stick your eyes right up to it for a long period of time and still be fine

What’s “a Long time”? Does it cover a 2 hour commute in traffic with 20+ cars around you blasting it continuously any direction you look, invisibly?

Laser safety ratings are based on what would happen if the laser was pointed directly at your eye continuously. In the case of general traffic each lidar is scanning in different direction and while manufacturers try to make the energy produced by their lasers instantaneously brighter than the sun in one specific wavelength but damage to your retina is caused by excessive heating and doesn't care about what wavelength the energy is coming in at in the IR except to the extend that it can get to the retina or not. In your morning commute I'd worry less about the lidars than the much larger amount of invisible IR radiation given off by the sun. And I'd worry much less about the sun's IR radiation than the sun's UV radiation, wearing sunglasses during a 2 hour commute is best for your eyes.

Re: A Short Introduction to Automotive Lidar Technology

#143

Post by hwillis »

deepnotderp wrote: post #46
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…

The SNR for flash Lidar is really low because you spread the beam out over such a large area. Most automotive Lidar already operate in a “photon starved regime”, ~200-300 photons per return[0]. If you spread that over the entire scene, your snr drops quickly. This forces you into 1550nm, and a large detector array and high power laser at 1550nm is extremely expensive. As for MEMS, it’s been a while but I think FOV/st…

> Most automotive Lidar already operate in a “photon starved regime”, ~200-300 photons per return[0]. If you spread that over the entire scene, your snr drops quickly.

Translating: Normally you have a large single sensor per laser, which makes measurements at a very high rate. With flash lidar, you split the sensor up like an image sensor. In a normal image sensor, each pixel can collect light for a long time, but if you do that with lidar you have no distance resolution. The sensor is sitting idle 99% of the time, and you pay in sensitivity and accuracy.

Array sensors, MEMs, and phased arrays all struggle because they're all really good at small-angle differences, while the reason for scanning lidar is large-angle differences. Maybe one day we'll start making curved dies and it'll be easier to have a really wide FOV without needing multiple sensors.

Re: A Short Introduction to Automotive Lidar Technology

#144

Post by 542354234235 »

jaimex2 wrote: post #109
bobsomers wrote: post #35

Earlier quoted context omitted.

Airplanes don't flap their wings and boats don't wag their tails. Assuming that all technology should imitate nature is a naive engineering principle. The solution should solve the problem within the given constraints.

Nature came up with something much better in both those cases. Portable, energy efficient, light, doesn't need refined oil, tightly steers... Boats and aeroplanes are terrible in comparison. They only work due to a huge network of global effort.

>They only work due to a huge network of global effort.

And horses don’t need roads like cars do and cars only work thanks to a huge network of global effort. What point are you trying to make? That we abandon planes until we can develop flight as efficient as nature? Abandoning LIDAR until we can develop visual light perception and processing equal to the human eye and brain?

Re: A Short Introduction to Automotive Lidar Technology

#145

Post by HPsquared »

raisedbyninjas wrote: post #124
rrr_oh_man wrote: post #122

Earlier quoted context omitted.

> Meanwhile, automotive companies aren't scared of moving parts. A car has loads of spinning parts already; they have mastered the art of making spinning things that can keep spinning for thousands of hours. Almost an understatement. A typical car wheel hub with a 20-27 inch tire diameter has experienced around 75-100M full rotations by the time it reaches 100K miles. Meanwhile, the engine probably has revolved ~5-10…

I may be wrong, but I think the concern was delicate components protruding from the body are susceptible to damage in urban areas.

Cars already have mirrors and lights etc. LIDAR is in the same family as those.

Re: A Short Introduction to Automotive Lidar Technology

#146

Post by denysvitali »

elictronic wrote: post #73
slt2021 wrote: post #72

LIDARs can be blinded by consumer grade laser pointers, I wonder if there are systems that protect LIDARs against adversarial attacks or DOS attacks

Drivers can also be blinded by consumer grade laser pointers. If someone starts attacking safety systems physically I would expect they will get quite a bit of jail time.

There are also (stupid) people who like to point laser pointers to helicopter pilots...

Re: A Short Introduction to Automotive Lidar Technology

#147

Post by Klaus23 »

tordrt wrote: post #121
Klaus23 wrote: post #44

Earlier quoted context omitted.

This is simply not true. Let's look at the best autonomous driving features available today, i.e. level 3: Mercedes Drive Pilot: Uses a lidar (and a dummy unit) up front. BMW Personal Pilot: Uses a lidar (and a dummy unit) up front Honda SENSING Elite: Uses 5! lidars They all use lidar, and some of the placement locations are downright hideous (Mercedes EQS). I think further development will require even more/better…

All of these are far less capable than FSD. They might have more advanced regulatory approval because they have strong limitations of when it can be used, but if you drive the same route and compare, its not even close.

I doubt it. Yes, FSD is more flexible and can also drive reasonably well on city streets, but there is a reason why it is not certified for level 3 on motorways. It would most likely fail certification. With a level 3 system, I can take my eyes off the road and watch a movie. Doing that with FSD, even in the best conditions, is suicidal. Level 3 vehicles must have an extremely low failure rate. Any crash would quickly be picked up by the media.

FSD is a versatile level 2 system, but at best a prototype for level 3. If we are talking about prototypes, it has to be compared to prototypes from other manufacturers like this https://www.youtube.com/watch?v=0uSph0asNsk> fully autonomous system from ... 11 years ago. The reason FSD is available to the average consumer is mostly a matter of philosophy, not technology.

Re: A Short Introduction to Automotive Lidar Technology

#148

Post by vel0city »

HPsquared wrote: post #145
raisedbyninjas wrote: post #124

Earlier quoted context omitted.

I may be wrong, but I think the concern was delicate components protruding from the body are susceptible to damage in urban areas.

Cars already have mirrors and lights etc. LIDAR is in the same family as those.

Mirrors and lights are generally cheaper than a whole LIDAR unit when I get lightly sideswiped.

Re: A Short Introduction to Automotive Lidar Technology

#149

Post by HPsquared »

vel0city wrote: post #148
HPsquared wrote: post #145

Earlier quoted context omitted.

Cars already have mirrors and lights etc. LIDAR is in the same family as those.

Mirrors and lights are generally cheaper than a whole LIDAR unit when I get lightly sideswiped.

I figure if the LIDAR is mass produced on every car, it won't be much more than a headlight. (Headlight prices notwithstanding)
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