4 ms·

This problem has been solved more than a decade ago by radar sensors (standard on many mid-range cars at the time). They detect imminent collisions with almost

by fsh 2y ago

This problem has been solved more than a decade ago by radar sensors (standard on many mid-range cars at the time). They detect imminent collisions with almost perfect accuracy and very little false positives. Having better sensor data is always going to beat trying to massage crappy data into something useful.

whiplash451 2y ago
Are we sure Teslas dont have radars? We know they don’t have lidars, but that’s irrelevant.
- pclmulqdq 2y ago
  Tesla Model 3's don't have radars. They had them at the beginning of the run, and removed them.
- daemonologist 2y ago
  Yes, they removed radar from their vehicles in 2021: https://www.tesla.com/support/transitioning-tesla-vision https://www.tesla.com/support/transitioning-tesla-vision (Also I wouldn't say it's _irrelevant_ that they don't have lidar, as if they did it would cover some of the same weaknesses as radar.)
- deleted 2y ago
  [deleted]
- rad_gruchalski 2y ago
  Yes. We are sure.
outside1234 2y ago
But what if you were on Ketamine and thought you could resolve it with a camera?
redox99 2y ago
Radars are not as good as you think. They generally can't detect stationary objects, have problems with reflections, most of them are VERY low resolution, and so on. The "with almost perfect accuracy and very little false positives" part is not true. If you look at euroncap data, you'll see how most cars are not close to 100 in Safety Assist category (and Teslas with just vision are among the top). And these EuroNCAP are fairly easy and ideal. So it's clearly not a solved problem, as you portray. https://www.euroncap.com/en/ratings-rewards/latest-safety-ratings/#?selectedMake=0&selectedMakeName=Select%20a%20make&selectedModel=0&selectedStar=&includeFullSafetyPackage=true&includeStandardSafetyPackage=true&selectedModelName=All&selectedProtocols=54301,51097,49446,45155,41776&selectedClasses=1202,1199,1201,1196,1205,1203,1198,1179,40250,1197,1204,1180,34736,44997,54278,54293&allClasses=true&allProtocols=false&allDriverAssistanceTechnologies=false&selectedDriverAssistanceTechnologies=&thirdRowFitment=false https://www.euroncap.com/en/ratings-rewards/latest-safety-ra...
- throwaway31131 2y ago
  > They generally can't detect stationary objects, have problems with reflections, most of them are VERY low resolution, and so on. Radar can absolutely detect a stationary object. The problem is not, "moving or not moving", it's "is the energy reflected back to the detector," as alluded to by your second qualification. So something that scatters or absorbs the transmitted energy is hard to measure with radar because the energy doesn't get back to the detector completing the measurement. This is the guiding principle behind stealth. And, as you mentioned, things with this property naturally occur. For example, trees with low hanging branches and bushes with sparse leaves can be difficult to get an accurate (say within 1 meter) distance measurement from.
  - potato3732842 2y ago
    Imagine if you could only see in a very narrow portion of the visible light spectrum, like only green or something. That's kind of how radar "sees" (I'm grossly over-simplifying here but point is it doesn't see the way we do). It's hard to tell something sticking off the back of a truck or a motorcycle behind a vehicle without false positive triggering off of other stuff and panic braking at dumb times, something early systems (generically, not any particular OEM) were known for, which is why they were mostly limited to warnings not actual braking. And while one can make bad faith comments all day about that not technically being the fault of the system doing the braking allowing such systems to proliferate would be a big class action lawsuit, and maybe even a revision of how liability is handled, waiting to happen.
mitthrowaway2 2y ago
Radar is great for detecting cars, not as great for detecting pedestrians.
hwillis 2y ago
Backing this up: automotive radar uses a band at ~80 GHz. The wavelength is ~3.7 millimeters, which lets you get incredible resolution. Not quite as good as the TSA airport scanners that can count your moles through your shirt, but good enough to see anything bigger than a golf ball. For a long, long time automotive radar was a pipe dream technology. Steering a phased array of antennas means delaying each antenna by 1/10,000s of a wave period. Dynamically steering means being able to adjust those timings![1] You're approaching picosecond timing, and doing that with 10s or 100s antennas. Reading that data stream is still beyond affordable technology. Sampling 100 antennas 10x per period at 16 bit precision is 160 terabytes per second, 100x more data than the best high speed cameras. Since the fourier transform is O(nlogn), that's tens of petaflops to transform. Hundreds of 5090s, fully maxed out, before running object recognition. Obviously we cut some corners instead. Current techniques way underutilize the potential of 80 GHz. Processing power trickles down slowly and new methods are created unpredictably, but improvement is happening. IMO radar has the highest ceiling potential of any of the sensing methods, it's the cheapest, and it's the most resistant to interference from other vehicles. Lidar can't hop frequencies or do any of the things we do to multiplex radar. [1]: In reality you don't scan left-right-up-down like that. You don't even use just an 80 GHz wave, or even just a chirp (a pulsing wave that oscillates between 77-80 GHz). You direct different beams in all different directions at the same time, and more importantly you listen from all different directions at the same time.
- porphyra 2y ago
  Agreed. Also, the fact that current automotive radars return a point cloud (instead of, say, a volumetric density grid) is sad. But it will be a while before processing power can catch up, and by the time you have the equivalent of hundreds of 5090s on your car, you will also be able to drive flawlessly by running a giant transformer model on vision inputs.
plun9 2y ago
This isn't true. You can try using adaptive cruise control with lane-keeping on a radar-equipped car on an undivided highway. Radar is good at detecting distance and velocity, but can't see lane lines. In order to prevent collisions, you would need to know precisely the road geometry and lane positions, which may come from camera data, and combine that information with the vehicle information.
- jamincan 2y ago
  I do this all the time with no problem at all. I drive a 2023 VW Taos, for what that is worth.

by fsh 2y ago

whiplash451 2y ago

Are we sure Teslas dont have radars? We know they don’t have lidars, but that’s irrelevant.

pclmulqdq 2y ago
Tesla Model 3's don't have radars. They had them at the beginning of the run, and removed them.
daemonologist 2y ago
Yes, they removed radar from their vehicles in 2021: https://www.tesla.com/support/transitioning-tesla-vision https://www.tesla.com/support/transitioning-tesla-vision (Also I wouldn't say it's _irrelevant_ that they don't have lidar, as if they did it would cover some of the same weaknesses as radar.)
deleted 2y ago
[deleted]
rad_gruchalski 2y ago
Yes. We are sure.

outside1234 2y ago

But what if you were on Ketamine and thought you could resolve it with a camera?

redox99 2y ago

Radars are not as good as you think. They generally can't detect stationary objects, have problems with reflections, most of them are VERY low resolution, and so on. The "with almost perfect accuracy and very little false positives" part is not true. If you look at euroncap data, you'll see how most cars are not close to 100 in Safety Assist category (and Teslas with just vision are among the top). And these EuroNCAP are fairly easy and ideal. So it's clearly not a solved problem, as you portray. https://www.euroncap.com/en/ratings-rewards/latest-safety-ratings/#?selectedMake=0&selectedMakeName=Select%20a%20make&selectedModel=0&selectedStar=&includeFullSafetyPackage=true&includeStandardSafetyPackage=true&selectedModelName=All&selectedProtocols=54301,51097,49446,45155,41776&selectedClasses=1202,1199,1201,1196,1205,1203,1198,1179,40250,1197,1204,1180,34736,44997,54278,54293&allClasses=true&allProtocols=false&allDriverAssistanceTechnologies=false&selectedDriverAssistanceTechnologies=&thirdRowFitment=false https://www.euroncap.com/en/ratings-rewards/latest-safety-ra...

throwaway31131 2y ago
> They generally can't detect stationary objects, have problems with reflections, most of them are VERY low resolution, and so on. Radar can absolutely detect a stationary object. The problem is not, "moving or not moving", it's "is the energy reflected back to the detector," as alluded to by your second qualification. So something that scatters or absorbs the transmitted energy is hard to measure with radar because the energy doesn't get back to the detector completing the measurement. This is the guiding principle behind stealth. And, as you mentioned, things with this property naturally occur. For example, trees with low hanging branches and bushes with sparse leaves can be difficult to get an accurate (say within 1 meter) distance measurement from.
- potato3732842 2y ago
  Imagine if you could only see in a very narrow portion of the visible light spectrum, like only green or something. That's kind of how radar "sees" (I'm grossly over-simplifying here but point is it doesn't see the way we do). It's hard to tell something sticking off the back of a truck or a motorcycle behind a vehicle without false positive triggering off of other stuff and panic braking at dumb times, something early systems (generically, not any particular OEM) were known for, which is why they were mostly limited to warnings not actual braking. And while one can make bad faith comments all day about that not technically being the fault of the system doing the braking allowing such systems to proliferate would be a big class action lawsuit, and maybe even a revision of how liability is handled, waiting to happen.

mitthrowaway2 2y ago

Radar is great for detecting cars, not as great for detecting pedestrians.

hwillis 2y ago

Backing this up: automotive radar uses a band at ~80 GHz. The wavelength is ~3.7 millimeters, which lets you get incredible resolution. Not quite as good as the TSA airport scanners that can count your moles through your shirt, but good enough to see anything bigger than a golf ball. For a long, long time automotive radar was a pipe dream technology. Steering a phased array of antennas means delaying each antenna by 1/10,000s of a wave period. Dynamically steering means being able to adjust those timings![1] You're approaching picosecond timing, and doing that with 10s or 100s antennas. Reading that data stream is still beyond affordable technology. Sampling 100 antennas 10x per period at 16 bit precision is 160 terabytes per second, 100x more data than the best high speed cameras. Since the fourier transform is O(nlogn), that's tens of petaflops to transform. Hundreds of 5090s, fully maxed out, before running object recognition. Obviously we cut some corners instead. Current techniques way underutilize the potential of 80 GHz. Processing power trickles down slowly and new methods are created unpredictably, but improvement is happening. IMO radar has the highest ceiling potential of any of the sensing methods, it's the cheapest, and it's the most resistant to interference from other vehicles. Lidar can't hop frequencies or do any of the things we do to multiplex radar. [1]: In reality you don't scan left-right-up-down like that. You don't even use just an 80 GHz wave, or even just a chirp (a pulsing wave that oscillates between 77-80 GHz). You direct different beams in all different directions at the same time, and more importantly you listen from all different directions at the same time.

porphyra 2y ago
Agreed. Also, the fact that current automotive radars return a point cloud (instead of, say, a volumetric density grid) is sad. But it will be a while before processing power can catch up, and by the time you have the equivalent of hundreds of 5090s on your car, you will also be able to drive flawlessly by running a giant transformer model on vision inputs.

plun9 2y ago

This isn't true. You can try using adaptive cruise control with lane-keeping on a radar-equipped car on an undivided highway. Radar is good at detecting distance and velocity, but can't see lane lines. In order to prevent collisions, you would need to know precisely the road geometry and lane positions, which may come from camera data, and combine that information with the vehicle information.

jamincan 2y ago
I do this all the time with no problem at all. I drive a 2023 VW Taos, for what that is worth.