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How the LIDAR tech GM just bought probably works

arstechnica.com

11–20 of 72 posts

Re: How the LIDAR tech GM just bought probably works

#11
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…

Isn't flash lidar range limited unless at a very high power output?

Re: How the LIDAR tech GM just bought probably works

#12
post #6
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).

While LIDAR and stereo cameras (as well as RGBD depth cameras like Kinect) both effectively do the same thing, LIDAR typically has a much longer effective range while keeping high resolution. To give you an example, this[1] commercially available sensor head can give great resolution stereo depth at around 10m but the included LIDAR unit is good out to around 30m. LIDAR also has the advantage of operating on a differ…

That sensor you linked looks to have its two cameras about 10cm apart. A car is easily 1.5m wide, giving a very cheap 15x increase in range for far objects and beating the LIDAR quote by a ton (and of course you can have multiple camera pairs for different distance ranges of course).

I'm with the grandparent: I genuinely don't understand the obsession with LIDAR in this space. It's complicated and fiddly, and seems to be competing with an "obvious" solution involving $3 camera parts.

Re: How the LIDAR tech GM just bought probably works

#13
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…

Isn't flash lidar range limited unless at a very high power output?

The peak power output is high, but only for a nanosecond or less.

Re: How the LIDAR tech GM just bought probably works

#14
Skimming those papers and reading about the silicon tunable lasers was a bit mind blowing.

I studied optics a bunch in college but never managed to work it into my electrical engineering job. Might be lame, but I didn't have any clue this kind of integration was possible yet, it's certainly quite exciting. Probably the coolest thing I've read about in quite some time.

Re: How the LIDAR tech GM just bought probably works

#15
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).

Don’t forget you can also drive reasonably well with one eye closed. The stereo stuff isn’t buying you much for driving.

Re: How the LIDAR tech GM just bought probably works

#17
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).

We don't want something that merely drives as well as a person. We want something that does better. To that end, if it is easier to build sensors that don't have to train so hard on just 2d images, why wouldn't we?

Re: How the LIDAR tech GM just bought probably works

#18
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…

> Sunlight tolerant is done with a few tricks. Narrow-band interference filters cut out everything but the color of the beam being used.

What about a beam collimator at the detector? It would reject a lot of noise but would cost some power.

Re: How the LIDAR tech GM just bought probably works

#19
post #12
post #6

Earlier quoted context omitted.

While LIDAR and stereo cameras (as well as RGBD depth cameras like Kinect) both effectively do the same thing, LIDAR typically has a much longer effective range while keeping high resolution. To give you an example, this[1] commercially available sensor head can give great resolution stereo depth at around 10m but the included LIDAR unit is good out to around 30m. LIDAR also has the advantage of operating on a differ…

That sensor you linked looks to have its two cameras about 10cm apart. A car is easily 1.5m wide, giving a very cheap 15x increase in range for far objects and beating the LIDAR quote by a ton (and of course you can have multiple camera pairs for different distance ranges of course). I'm with the grandparent: I genuinely don't understand the obsession with LIDAR in this space. It's complicated and fiddly, and seems t…

More cameras still doesn't fix the interaction with ambient light and LIDAR units like the ones produced by Velodyne or Ibeo have ranges out to 200m[1]

Again, I think they both have their uses. If LIDAR can be made not so complicated and fiddly, I think it brings a lot to the table.

[1]: https://autonomoustuff.com/product/ibeo-lux-standard/

Re: How the LIDAR tech GM just bought probably works

#20
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.
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