5 ms·

Why aren't we using sonar for this sort of thing. Bats have nailed down the echo location thing in extremely heavy bat traffic, but I don't see that being somet

Why aren't we using sonar for this sort of thing. Bats have nailed down the echo location thing in extremely heavy bat traffic, but I don't see that being something that has been vigorously pursued by tech companies.

jasonjei 9y ago
A lot of companies (such as Google/ABC Waymo) are actually looking into Lidar applications. Sonar is good, but Lidar is an order of magnitude faster. In fact, 1,000,000 times faster than speed of sound.
- metamet 9y ago
  Have they overcome the hacking/tricking issues they were having a few years ago yet? https://www.theguardian.com/technology/2015/sep/07/hackers-trick-self-driving-cars-lidar-sensor https://www.theguardian.com/technology/2015/sep/07/hackers-t... Side note: I can't help but be reminded of Napoleon Dynamite's Liger whenever I see Lidar. Makes me smile.
  - knodi123 9y ago
    How timely. That's the very topic of today's xkcd. https://www.xkcd.com/1958/ https://www.xkcd.com/1958/ Short version: Regular cars are vulnerable to malicious actors, too, but luckily most people aren't murderers.
screye 9y ago
Lidar kind of works the same way, but is a lot faster (speed of light vs speed of sound) I could also see sonar taking a lot more energy to use all the time as compared to Lidar.
- cr0sh 9y ago
  No, it probably has more to do with your first point: speed. During the time it could take for a sonar (ultrasonic) sensor to send out a pulse and for it to return, the car may have travelled many feet depending on speed and road conditions. This would impact how long it would take to perform an evasive action and return to a safe state. That is just a guess, though - I haven't run the numbers to know if it is factual. Lidar, though, is much quicker, as you noted.
- mandevil 9y ago
  LIDAR has severe range limitations, such that it's basically unusable for highway speed driving (or at least did, <mumble> years ago when I worked on autonomous driving), which is why Tesla doesn't use LIDAR. Looking at Thrun et al.'s paper on Stanley (https://www-cs.stanford.edu/people/dstavens/jfr06/thrun_etal_jfr06.pdf https://www-cs.stanford.edu/people/dstavens/jfr06/thrun_etal...): "The effective maximum range at which obstacles can be detected with the laser mapper is approximately 22 m. This range is sufficient for Stanley to reliably avoid obstacles at speeds up to 25 mph. Based on the 2004 Race Course, the development team estimated that Stanley would need to reach speeds of 35 mph in order to successfully complete the challenge. To extend the sensor range enough to allow safe driving at 35 mph, Stanley uses a color camera to find drivable surfaces at ranges exceeding that of the laser analysis." They built a neural network to analyze terrain and find safe paths- and trained it driving at 25 mph across the environment with the LIDAR providing the control- and then let it work at higher speeds where the LIDAR would be able to panic stop but not much more.
  - giobox 9y ago
    I may be way off base here, but hasn't the LIDAR field evolved enormously since 2006 (date of that paper)? Last I read prototype solid state LIDAR systems have ranges in the ~150m range, although I don't follow this field all that closely. Given that the major players like Waymo/Uber/Apple etc seem to be betting very heavily on LIDAR, one would assume these challenges are being resolved. I suspect the traditionally very high cost of LIDAR was likely a much bigger factor in Tesla's decision not to use, rather than any technical reason. Cameras plus radar is vastly cheaper to ship for now.
dwighttk 9y ago
bats aren't traveling 70mph, are they?
- SimbaOnSteroids 9y ago
  No but they're also flying in much closer tighter quarters.
  - nharada 9y ago
    I think that's kinda the parent comment's point. Just because sonar is good for indoor localization doesn't mean it's got the range for highway speeds. In fact, ultrasound on cars is for exactly this: low speed, close quarters detection. This is why backup sensors or self parking systems rely on ultrasound.
  - grkvlt 9y ago
    Is there the equivalent of Reynolds number for this? I'm guessing something based on a characteristic length and velocity? It looks like I want the Walking Froude Number [0] which is Fr = u^2 / g.l it seems... 0. https://en.wikipedia.org/wiki/Froude_number#Walking_Froude_number https://en.wikipedia.org/wiki/Froude_number#Walking_Froude_n...
  - Terretta 9y ago
    Closer relative to their size? Cars often travel in packs closer together than unit size.
chromaton 9y ago
The article mentions Tesla's use of ultrasonic sensors.
seanmcdirmid 9y ago
LIDAR is still expensive, so is used in the lab (or in test vehicles) but I don't think it has been used in a consumer vehicle yet, which I think are mostly using cheaper eye-like cameras.
- cr0sh 9y ago
  High-resolution, 3D lidar is expensive, not to mention mechanically complicated and large, so it doesn't fit well into car designs...no consumer is going to want a spinning top on their car (Waymo's Velodyne lidar). 2D lidar is less expensive, but still isn't cheap enough for the number of sensors that would be needed (multiple sensors would be needed for proper coverage, if the the sensors were incorporated into the car body); also, they are still mechanically complex (most rely on spinning mirrors or sensors). That leaves something like flash lidar, which isn't quite cheap enough (though it's dropped in price significantly in recent years), and I think it's resolution is still fairly low - but it does allow for 3D information about the scene, within it's field of view. I have always understood why Tesla took the route of using cameras only. In theory, it should work fairly well, since humans have been using a similar system for 100+ years for driving automobiles. It really comes down to a software problem (vision and deep learning, etc), more than anything. Camera sensors are inexpensive, and easy to incorporate into a vehicle. I tend to wonder if maybe augmentation with FLIR and other wavelength sensors might not improve things, but even standalone image sensors - in theory - should be completely workable.
  - greglindahl 9y ago
    Tesla doesn't use cameras only. They use cameras, radar, and ultrasound.
- SimbaOnSteroids 9y ago
  Also iirc current LIDAR hardware is rather large and needs to placed in a fairly open and visible position. The HN demographic may not appreciate this as much as they should but looks are really important when it comes to selling a car, a LiDAR set is unsightly. LiDAR-less maybe the only market viable option.
jjtheblunt 9y ago
rain and wind would screw sonar up, no?
bonestamp2 9y ago
They kind of do... Tesla uses 12 ultrasonic (sonar) sensors (and cameras). GM uses radar (and cameras).
- greglindahl 9y ago
  Tesla also has a radar.

jasonjei 9y ago

A lot of companies (such as Google/ABC Waymo) are actually looking into Lidar applications. Sonar is good, but Lidar is an order of magnitude faster. In fact, 1,000,000 times faster than speed of sound.

metamet 9y ago
Have they overcome the hacking/tricking issues they were having a few years ago yet? https://www.theguardian.com/technology/2015/sep/07/hackers-trick-self-driving-cars-lidar-sensor https://www.theguardian.com/technology/2015/sep/07/hackers-t... Side note: I can't help but be reminded of Napoleon Dynamite's Liger whenever I see Lidar. Makes me smile.
- knodi123 9y ago
  How timely. That's the very topic of today's xkcd. https://www.xkcd.com/1958/ https://www.xkcd.com/1958/ Short version: Regular cars are vulnerable to malicious actors, too, but luckily most people aren't murderers.

screye 9y ago

Lidar kind of works the same way, but is a lot faster (speed of light vs speed of sound) I could also see sonar taking a lot more energy to use all the time as compared to Lidar.

cr0sh 9y ago
No, it probably has more to do with your first point: speed. During the time it could take for a sonar (ultrasonic) sensor to send out a pulse and for it to return, the car may have travelled many feet depending on speed and road conditions. This would impact how long it would take to perform an evasive action and return to a safe state. That is just a guess, though - I haven't run the numbers to know if it is factual. Lidar, though, is much quicker, as you noted.
mandevil 9y ago
LIDAR has severe range limitations, such that it's basically unusable for highway speed driving (or at least did, <mumble> years ago when I worked on autonomous driving), which is why Tesla doesn't use LIDAR. Looking at Thrun et al.'s paper on Stanley (https://www-cs.stanford.edu/people/dstavens/jfr06/thrun_etal_jfr06.pdf https://www-cs.stanford.edu/people/dstavens/jfr06/thrun_etal...): "The effective maximum range at which obstacles can be detected with the laser mapper is approximately 22 m. This range is sufficient for Stanley to reliably avoid obstacles at speeds up to 25 mph. Based on the 2004 Race Course, the development team estimated that Stanley would need to reach speeds of 35 mph in order to successfully complete the challenge. To extend the sensor range enough to allow safe driving at 35 mph, Stanley uses a color camera to find drivable surfaces at ranges exceeding that of the laser analysis." They built a neural network to analyze terrain and find safe paths- and trained it driving at 25 mph across the environment with the LIDAR providing the control- and then let it work at higher speeds where the LIDAR would be able to panic stop but not much more.
- giobox 9y ago
  I may be way off base here, but hasn't the LIDAR field evolved enormously since 2006 (date of that paper)? Last I read prototype solid state LIDAR systems have ranges in the ~150m range, although I don't follow this field all that closely. Given that the major players like Waymo/Uber/Apple etc seem to be betting very heavily on LIDAR, one would assume these challenges are being resolved. I suspect the traditionally very high cost of LIDAR was likely a much bigger factor in Tesla's decision not to use, rather than any technical reason. Cameras plus radar is vastly cheaper to ship for now.

dwighttk 9y ago

bats aren't traveling 70mph, are they?

SimbaOnSteroids 9y ago
No but they're also flying in much closer tighter quarters.
- nharada 9y ago
  I think that's kinda the parent comment's point. Just because sonar is good for indoor localization doesn't mean it's got the range for highway speeds. In fact, ultrasound on cars is for exactly this: low speed, close quarters detection. This is why backup sensors or self parking systems rely on ultrasound.
- grkvlt 9y ago
  Is there the equivalent of Reynolds number for this? I'm guessing something based on a characteristic length and velocity? It looks like I want the Walking Froude Number [0] which is Fr = u^2 / g.l it seems... 0. https://en.wikipedia.org/wiki/Froude_number#Walking_Froude_number https://en.wikipedia.org/wiki/Froude_number#Walking_Froude_n...
- Terretta 9y ago
  Closer relative to their size? Cars often travel in packs closer together than unit size.

chromaton 9y ago

The article mentions Tesla's use of ultrasonic sensors.

seanmcdirmid 9y ago

LIDAR is still expensive, so is used in the lab (or in test vehicles) but I don't think it has been used in a consumer vehicle yet, which I think are mostly using cheaper eye-like cameras.

cr0sh 9y ago
High-resolution, 3D lidar is expensive, not to mention mechanically complicated and large, so it doesn't fit well into car designs...no consumer is going to want a spinning top on their car (Waymo's Velodyne lidar). 2D lidar is less expensive, but still isn't cheap enough for the number of sensors that would be needed (multiple sensors would be needed for proper coverage, if the the sensors were incorporated into the car body); also, they are still mechanically complex (most rely on spinning mirrors or sensors). That leaves something like flash lidar, which isn't quite cheap enough (though it's dropped in price significantly in recent years), and I think it's resolution is still fairly low - but it does allow for 3D information about the scene, within it's field of view. I have always understood why Tesla took the route of using cameras only. In theory, it should work fairly well, since humans have been using a similar system for 100+ years for driving automobiles. It really comes down to a software problem (vision and deep learning, etc), more than anything. Camera sensors are inexpensive, and easy to incorporate into a vehicle. I tend to wonder if maybe augmentation with FLIR and other wavelength sensors might not improve things, but even standalone image sensors - in theory - should be completely workable.
- greglindahl 9y ago
  Tesla doesn't use cameras only. They use cameras, radar, and ultrasound.
SimbaOnSteroids 9y ago
Also iirc current LIDAR hardware is rather large and needs to placed in a fairly open and visible position. The HN demographic may not appreciate this as much as they should but looks are really important when it comes to selling a car, a LiDAR set is unsightly. LiDAR-less maybe the only market viable option.

jjtheblunt 9y ago

rain and wind would screw sonar up, no?

bonestamp2 9y ago

They kind of do... Tesla uses 12 ultrasonic (sonar) sensors (and cameras). GM uses radar (and cameras).

greglindahl 9y ago
Tesla also has a radar.