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How the LIDAR tech GM just bought probably works

arstechnica.com

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Re: How the LIDAR tech GM just bought probably works

#41

Post by Symmetry »

madengr wrote: post #3

I assume LIDAR is needed since the AI isn't advanced enough to do depth perception? If I can drive with two eye balls, then I'd think a circular camera array would be plenty. Maybe this is what Tesla plans on using (in combination with RADAR).

If you're moving through easy to distinguish objects then optical flow is usually enough to provide depth and avoid hitting things. But not always. Your eye+retina are still a better camera and processing system than anything we can produce artificially at tasks like this. I'd bet a machine could do as well in 5 years or so but not now.

Re: How the LIDAR tech GM just bought probably works

#42

Post by leohutson »

madengr wrote: post #3

I assume LIDAR is needed since the AI isn't advanced enough to do depth perception? If I can drive with two eye balls, then I'd think a circular camera array would be plenty. Maybe this is what Tesla plans on using (in combination with RADAR).

By analogy, why don't we make planes that are flappy winged ornithopters? It works for birds.

Re: How the LIDAR tech GM just bought probably works

#43

Post by alkonaut »

baybal2 wrote: post #28

I genuinely don't understand obsession with LIDARs in the autonomous vehicle community, a millimetre wave radar is late seventies tech, does the job many times better, for less money, and can be made by an electronics engineering undergrad from radio shack parts. Commies had them in such abundance that they put millimetre wave imagers (and that was in seventies) on thing as cheap as vision aids for tank drivers, fiel…

What's the difference in e.g. surface ice handling between optical and radar?

I worry that these modern cars will be basically requiring fighter jet storage in order to work. I need something that works in a snowstorm when the car is covered in ice.

My "parking sensors" (the cheap little distance sensing thingys mounted around most new cars) are screaming every time there is a little surface ice over them. I work around this by simply ignoring it. But if a car would require these sensors to function, which would be the case if it was autonomous, I'd be starting my morning drive by somehow getting the ice off them.

Re: How the LIDAR tech GM just bought probably works

#44

Post by alkonaut »

xbryanx wrote: post #20
generj wrote: post #2

One of the advantages for solid-state LIDAR has to be an increase in reliability. Nobody wants to buy a car which requires a new LIDAR to be installed after 100,000 miles for the sum of $7,000. Hopefully once production starts and yield rates increase the unit costs can shrink small enough to being becoming feasible for integration into lower-end products like cell phones or laptops. I think there are a lot of cool a…

That brings up an interesting thought. Self-driving cars are going to have to come with automated tests that must be passed for the car to even start. You won't be able to make a choice about whether to drive around with a slightly broken car part like that. Some parts of the system will have to not only work, but work near perfectly or require service.

> You won't be able to make a choice about whether to drive around with a slightly broken car part like that.

As I mentioned in another post: cars already have these sensors in the form of short range (ultrasound?) sensors for parking. These are regularly covered with ice if you live in a winter climate, and in that situation the parking sensors will continuously beep when you have the car in reverse. A human driver just ignores that and backs out anyway, because you look with your eyes and see nothing, so you assume the warning is false and due to ice. The device isn't even broken, it's just temporarily not able to work until the ice has melted, which is a few hours away when the sun comes up.

An autonomous car could just say "I don't trust the readings from the sensors so you are on your own kid" and I'd drive. And that would be sort of fine (although it can't be several dozen mornings then it's annoying).

But an autonomous taxi can't do that. This is why I think assistant drivers such as teslas autopilot, that can just defer driving to a human, will be around for a very long time (Decades) before we have fully autonomous cars that can drive without backup driver.

Re: How the LIDAR tech GM just bought probably works

#45

Post by dllu »

baybal2 wrote: post #28

I genuinely don't understand obsession with LIDARs in the autonomous vehicle community, a millimetre wave radar is late seventies tech, does the job many times better, for less money, and can be made by an electronics engineering undergrad from radio shack parts. Commies had them in such abundance that they put millimetre wave imagers (and that was in seventies) on thing as cheap as vision aids for tank drivers, fiel…

I don't see how you can say millimetre wave radar "does the job many times better".

State-of-the art 79 GHz automotive radar: 0.2 m range uncertainty, 5 degree azimuth angular uncertainty, dozens of points per second.

Spinning lidar: Radar definitely has its uses as it can see through weather conditions and tell velocity, but lidar is the vastly superior sensor otherwise.

Re: How the LIDAR tech GM just bought probably works

#46

Post by mikeha »

joshvm wrote: post #31
Animats wrote: post #9

Interesting. Frequency-modulated continuous-wave LIDAR is easy to do as a one-point device. Many such devices have been built. But they're usually short range, such as the discontinued Swiss Ranger, and don't reject ambient light as effectively as pulse systems. Being both eye-safe and sunlight-tolerant is hard. Eye-safe is easier if you can increase the diameter of the outgoing beam. Eye safety is measured based on…

The Mesa Imaging SwissRanger is an amplitude modulated system, not frequency modulated. It's also not really LIDAR, as it uses LED illumination, but AMCW LIDAR is more or less the same principle. A better comparison might be laser tape measures - these often use phase modulated LIDAR rather than direct ToF. You can also buy phase shift scanning systems from people like Leica Geosystems. In a ToF camera (at least some…

Leica Geosystems used to sell phase-based scanners. These units were actually rebadged Zoller+Frohlich scanners. But the partnership ended a few years ago when Leica introduced the Pxx series. Today the company only makes time-of-flight scanners.

source: I work at Leica Geosystems.

Re: How the LIDAR tech GM just bought probably works

#47

Post by baybal2 »

dllu wrote: post #45
baybal2 wrote: post #28

I genuinely don't understand obsession with LIDARs in the autonomous vehicle community, a millimetre wave radar is late seventies tech, does the job many times better, for less money, and can be made by an electronics engineering undergrad from radio shack parts. Commies had them in such abundance that they put millimetre wave imagers (and that was in seventies) on thing as cheap as vision aids for tank drivers, fiel…

I don't see how you can say millimetre wave radar "does the job many times better". State-of-the art 79 GHz automotive radar: 0.2 m range uncertainty, 5 degree azimuth angular uncertainty, dozens of points per second. Spinning lidar: Radar definitely has its uses as it can see through weather conditions and tell velocity, but lidar is the vastly superior sensor otherwise.

Looks surprisingly close to specs of a Panasonic made radar.

That is far from what is currently considered advanced for mm-wave radar in 93-95ghz range - 0.5 degrees

Google "GPU Acceleration of SAR/ISAR Imaging Algorithms" and see how much you can get with with regular high bandwidth 10ghz radar and computing power in tenths of gigaflops.

Re: How the LIDAR tech GM just bought probably works

#48

Post by deepnotderp »

baybal2 wrote: post #37
deepnotderp wrote: post #30

Earlier quoted context omitted.

Resolution?

Theoretical one is lower than that of lidar, but in practice a well made mm-wave radar, currently, has superior resolution to commercially available lidars

Can you point to any reasonably priced mm wave radar that has greater than lidar resolution? Genuine question.

Re: How the LIDAR tech GM just bought probably works

#49

Post by samstave »

OK I have a question, but dont shit on me if you think its stupid:

Wouldnt any of these smart cars be able to know they physical volumes of many number of cars, including themselves, as well as communicate with eachother - and share their velocity, direction, volume, intentions so as to have a hive mind of the moving bodies?

What if you also just had a beacon which reported this information to other cars in a short network where the driver is human - so the smart cars all know where the human driver operated cars are.

Then, in addition, you collect all the point data, from lidar, you subtract the known data points given "a prius with a shape and mass and volume of this moving at a speed of that - and over time you have built out a complete point cloud of the static, non-variable topology?

rather than spending $75,000 on one lidar periscope, spend 75,000 on developing a beacon such that all cars are telling eachother where they are, their mass/volume and speed?

Re: How the LIDAR tech GM just bought probably works

#50

Post by grzm »

samstave wrote: post #49

OK I have a question, but dont shit on me if you think its stupid: Wouldnt any of these smart cars be able to know they physical volumes of many number of cars, including themselves, as well as communicate with eachother - and share their velocity, direction, volume, intentions so as to have a hive mind of the moving bodies? What if you also just had a beacon which reported this information to other cars in a short n…

(Assuming I'm understanding you correctly,) if the issue were only other vehicles, this might be feasible. However, the world includes much more than just the other vehicles on the road, and the road and its environs aren't static.

I can imagine something similar to what you're proposing being a part of the overall system, I suspect there will always be the need for something vehicle-based that "sees" the environment.

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