Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Why Tesla removed radar and ultrasonic sensors [video]

youtube.com

Post reply on HN
Print view View original

321–330 of 483 posts

Re: Why Tesla removed radar and ultrasonic sensors [video]

#321

Post by michaelt »

touisteur wrote: post #310
Reason077 wrote: post #253

Earlier quoted context omitted.

> ”The first famous autopilot crash was because a white semi-truck was washed out by the sun and confused for an overhead sign. That's literally trivial for a car with radar to detect.” That crash occurred on a car which was using radar. Automotive radar generally doesn’t help to detect stationary objects. Further, that crash occurred on a vehicle with the original autopilot version (AP1), which was based on Mobileye…

I find very strange the claim that a moving doppler (pulsed doppler?) radar 'generally doesn't help to detect stationary objects'. I mean if the car is moving, it generates a doppler shift on all objects moving at a different speed, right? Maybe it's difficult for reasons of false alarm detection (too many stationary objects that are not of interest) but you can get very good results with tracking (curious about thes…

I've heard people on the internet claim that, in automotive radar the first thing they do when processing the signal is discard any stationary objects. Apparently this is because the vast majority of the time it's a sign or overhead gantry or guard rail - any of which could plausibly be very close to the lane of travel thousands of times per journey - and radar doesn't provide enough angular resolution to tell the difference.

Personally I've never seen these claims come from the mouth of an automotive radar expert, and many cars do use radar in their adaptive cruise control, so I present it as a rumour, not a fact :)

Re: Why Tesla removed radar and ultrasonic sensors [video]

#322

Post by xodjmk »

YZF wrote: post #290
xodjmk wrote: post #282

Earlier quoted context omitted.

I am an engineer working on autonomous vehicles. Nothing personal just responding to the thread as a whole. I don't believe this guy is conspiring to trick anyone. Business decisions, or course. I think they are in good faith gambling on this one approach. So I am interested to see if their idea will win, or if someone else figures out a better way.

There problem is not that he was wrong, the problem is that he's made a motherhood statement in response to a very specific question. He's not conspiring to trick people per se but he's also not being super clear. His position obviously makes it difficult to answer this question. It's possible he really believes this is better but if he didn't he wouldn't exactly tell us something that makes him and his previous empl…

Maybe you're right, I don't care about Tesla drama.

Here is one possible perspective from an engineering standpoint:

Same amount of $$, same amount of software complexity, same size of engineering teams, same amount of engineering hours, same amount of moving parts. One company focuses on multiple different sensors and complex fusion with some reliance on AI. Another company focuses on limited sensors and more reliance on AI. Which is better? I don't think the answer is clear.

The other point is that I am arguing that many people are over-stating the importance of the sensors. They are important, but far more important is the post-processing. Any raw sensor data is a poor actual representation of the real environment. It is not about the sensors, but about everything else. The brain or the post-sensor processing is responsible for reconstructing an approximation of the environment. We have to infer from previous learned experiences of the 3D world to successfully navigate. There is no 3D information coming in from sensors, no objects, no motion, no corners, no shadows, no faces, etc. That is all constructed later. So whoever does a better job at the post-processing will probably out perform regardless of the choice of sensors.

Re: Why Tesla removed radar and ultrasonic sensors [video]

#323

Post by Beldin »

xodjmk wrote: post #232
mbreese wrote: post #171

Earlier quoted context omitted.

Sadly, that’s the worst way to actually design the system. I’d rather have two different technologies working together, with different failure modes. Not using radar (especially in cars that are already equipped) might make economic sense to Tesla, but I’d feel safer if visual processing was used WITH radar as opposed to instead of radar. I also expect an automated system to be better than the poor human in the drive…

You have to eventually decide to trust one or the other, in real-time. So having multiple failure modes doesn't solve the problem entirely. This is called 'Fusion', meaning you have to fuse information coming from multiple sensors together. There are trade offs because while you gain different views of the environment from different sensors, the fusion becomes more complicated and has to be sorted out in software rel…

> You have to eventually decide to trust one or the other, in real-time.

More or less. You can take that decision on other grounds - e.g. "what would be safest to do if one of them is wrong and i don't know which one?"

The system is not making a choice between two sensors, but determining a way to act given unreliable/contradictory information. If both sensors allow for going to the emergency lane and stopping, maybe that's the best thing to do.

Re: Why Tesla removed radar and ultrasonic sensors [video]

#324

Post by atoav »

seanmcdirmid wrote: post #236
flashgordon wrote: post #51

Earlier quoted context omitted.

That was hilarious. Basically (unless this needs a reframing/realignment/repositioning/reorienting): Q: "are less sensors less safe/effective?" A: "well more sensors are costly to the organization and add more tech debt so safety is orthogonal and not worth answering".

It is a hard question to answer. It’s like asking if more programmers on a project will allow it to be completed faster with higher quality. Ya, theoretically they could, in practice not likely. More sensors are like more programmers, theoretically they can be safer and more effective, but in practice they won’t be. Sensor fusion is as hard a problem as scaling up a software team.

I mean yeah, but it is a friggin ton heavy object moving at high speed controlled by a computer. Having another kind of sensor system to cross-check might be the reasonable thing to have, even if you happen to make it work well in 99% of the cases just with optics — the issue is that the other 1% kill people.

Your optical system can be good as heck till a bug hits it directly on the lense coving an important frontal area and make it behave weirdly.

Re: Why Tesla removed radar and ultrasonic sensors [video]

#325

Post by lnsru »

oxplot wrote: post #313
lnsru wrote: post #289

Earlier quoted context omitted.

360 degree camera on BMW i4. Overall build quality too.

I don't know if you're addressing what makes a good "EV" or just listing some features you personally care about. If the former, then 360 degree camera and build quality has little to do with an EV. Tesla is a young company and build quality has dramatically improved over the years (see Munro) and will continue to do so. Tesla has close to 360 camera coverage, it just hasn't added it in software. All it takes is a so…

Maybe in US. Tesla has nothing to throw against some serious cars like Mercedes EQS or EQS SUV. Hyundai is also catching up. Charging infrastructure isn’t an issue in Europe anymore and is getting better and better every year. Tesla supercharger for free at the beginning was a big deal. That’s why I am looking for used model X from 2017 right now. 5000€ in free electricity a year is a nice advantage. I also have open order for model Y performance from Berlin factory. Sorry, the lead time shitshow is similar to all others. Every month my order is being delayed by 2 months for months. I have only one additional option ordered - black color. Last time I checked delivery time was updated to “TBD”. Lol.

Edit: this year generous funding for new electric vehicles in Germany is about to end, that’s why the last months of 2022 are so chaotic regarding lead times.

Re: Why Tesla removed radar and ultrasonic sensors [video]

#326

Post by whiddershins »

aeternum wrote: post #96
petilon wrote: post #33

I didn't find his answers particularly convincing. His answer focused on costs mainly, and how "the best part is no part". We have already seen multiple accidents caused by camera's limitations [1] which would not have happened if Tesla used Lidars. Cameras have poor dynamic range and can be easily blinded by bright surfaces. While it is true that humans do fine with only eyes, our eyes are significantly better than…

The dynamic range is the reason Tesla know counts photons rather than use traditional camera processing. They basically remove the concept of exposure entirely and simply pass the sensor photon counts to the neural net. This approach not only simpler as it removes photo processing/encoding but the result is that the NN can operate with a very high dynamic range similar to the human eye and in many cases can be sensit…

The replies to your comment don't seem to understand you at all. in the video link here

https://youtu.be/ODSJsviD_SU?t=4424

he clearly states 16x dynamic range as a result of direct photon processing.

Re: Why Tesla removed radar and ultrasonic sensors [video]

#327

Post by patrec »

ClumsyPilot wrote: post #190
patrec wrote: post #72

Earlier quoted context omitted.

> I thought it was telling that Andrej immediately "reframed" the question because Lex asked the "wrong question". This is a classic evasion technique I agree with this assessment. However: > Telsa can't support additional sensors without incurring a prohibitive amount of additional risk to Tesla. Risk to passengers doesn't appear to be a consideration. This is a stupidifying take. Of course when you work in a line o…

> risks to passengers will absolutely affect your bottom line and if are rational you will take them into consideration percieved, not real risks to customers. PR matters more than reality

It is kind of hard to control perceived risks to passengers without taking actual risks to them into account.

Re: Why Tesla removed radar and ultrasonic sensors [video]

#328

Post by jholman »

flashgordon wrote: post #51
CharlesW wrote: post #11

I thought it was telling that Andrej immediately "reframed" the question because Lex asked the "wrong question". This is a classic evasion technique one learns from experience and/or media training. Lex's comment immediately after was a clever and gentle dig at Andrej's response. It seemed like all the "full cost" negatives Andrej mentioned were related to Tesla's ability to execute, and not what would actually produ…

That was hilarious. Basically (unless this needs a reframing/realignment/repositioning/reorienting): Q: "are less sensors less safe/effective?" A: "well more sensors are costly to the organization and add more tech debt so safety is orthogonal and not worth answering".

Uh, that's not at all a good paraphrase.

Q: "Does [removing some sensors] make the perception problem harder, or easier?"

(note, this is literally what Lex asked, your restatement is misleading)

A: [paraphrasing] "Well more sensor diversity makes it harder to focus on the thing that I believe really moves the needle, so by narrowing the space of consideration, I think we'll get better results"

Karpathy might not be telling the truth, I don't know. But it's a much more credible pitch than you make it sound, because it's often true that you can deliver better by focusing on a smaller number of things. Engineering has always been about tradeoffs. Nobody is offering Karpathy infinite money plus infinite resources plus infinite time to do the job.

Again, I'm not saying Karpathy is honest or correct. I'm saying that the rephrasings in this comment and this thread are hilariously unfair.

Re: Why Tesla removed radar and ultrasonic sensors [video]

#329

Post by flashgordon »

jholman wrote: post #328
flashgordon wrote: post #51

Earlier quoted context omitted.

That was hilarious. Basically (unless this needs a reframing/realignment/repositioning/reorienting): Q: "are less sensors less safe/effective?" A: "well more sensors are costly to the organization and add more tech debt so safety is orthogonal and not worth answering".

Uh, that's not at all a good paraphrase. Q: "Does [removing some sensors] make the perception problem harder, or easier?" (note, this is literally what Lex asked, your restatement is misleading) A: [paraphrasing] "Well more sensor diversity makes it harder to focus on the thing that I believe really moves the needle, so by narrowing the space of consideration, I think we'll get better results" Karpathy might not be t…

Actually that's a fair point. My goal was only for simplification and not intended to malign.
Post reply on HN