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Why Tesla removed radar and ultrasonic sensors [video]

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

#291

Post by stillworks »

RC_ITR wrote: post #208
stefan_ wrote: post #141

Earlier quoted context omitted.

This thread is unhelpfully mixing radar and ultrasonic sensors. Ultrasonic sensors, as your video explains, are primarily used as a parking aid; they are tuned for too low a distance to be helpful in just about any kind of driving scenario at speed. Meanwhile, radar is the principal sensor used in systems like automatic emergency braking across the industry. It has no intersection with any of the parking stuff becaus…

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. Amazing how people talk about stuff they have no idea about when it comes to Tesla.

  That's literally trivial for a car with radar to detect.
In principle that is correct… but radars in automotive application are unable (or rather not used) to detect non-moving targets ?

Asking this because I know first hand that the adaptive cruise function in my car must have a moving vehicle in front of it for the adaptive aspect to work. It will not detect a vehicle that is already stopped.

The resolution of the radar is pretty good though, even if the vehicle in the front is just merely creeping off breaks… it does get detected if it is at or more than the “cruising distance” set up initially.

The AEB function on my car depends on the camera.

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

#293

Post by cbsmith »

stillworks wrote: post #291
RC_ITR wrote: post #208

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. Amazing how people talk about stuff they have no idea about when it comes to Tesla.

That's literally trivial for a car with radar to detect. In principle that is correct… but radars in automotive application are unable (or rather not used) to detect non-moving targets ? Asking this because I know first hand that the adaptive cruise function in my car must have a moving vehicle in front of it for the adaptive aspect to work. It will not detect a vehicle that is already stopped. The resolution of the…

Adaptive cruise control is solving a totally different problem. It is specifically looking for moving objects to match pace with. That's very different from autonomous driving systems.

Radar is quite good at finding stationary metal objects, particularly. Putting it in a car, if anything, helps, because the station objects are more likely to be moving relative to the car...

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

#294

Post by cbsmith »

kalleboo wrote: post #252
RC_ITR wrote: post #248

Earlier quoted context omitted.

So, yes, cars that are programmed to have AEB: perform well at AEB and not other tasks. We are in agreement here. (I even agree with you that those cars use Radar for AEB). Now, where we disagree is you implying that cars with AEB-level radar (literally $10 off-the-shelf parts with whatever sensor fusion some MobilEye intern dreams ups) are somehow the same as self-driving cars (the goal of Tesla Autopilot). Every se…

But if the radar just sees a static object and can't tell if it's an overhead sign or a car, and the camera vision is too washed out, how would sensor fusion help in your example?

Lidar would make it pretty obvious whether it's a sign or a car, even if the camera didn't tell you. The part where the lidar doesn't bounce back at vehicle level would be a dead give away.

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

#295

Post by cbsmith »

Reason077 wrote: post #257
RC_ITR wrote: post #248

Earlier quoted context omitted.

So, yes, cars that are programmed to have AEB: perform well at AEB and not other tasks. We are in agreement here. (I even agree with you that those cars use Radar for AEB). Now, where we disagree is you implying that cars with AEB-level radar (literally $10 off-the-shelf parts with whatever sensor fusion some MobilEye intern dreams ups) are somehow the same as self-driving cars (the goal of Tesla Autopilot). Every se…

> ”There is no one sensor that will do it. Full stop.” Yet somehow, humans can drive cars with just a pair of optical sensors (mounted on a swivelling gimbal, of sorts). In theory, a sufficiently capable AI should be able to drive a car at least as well as a human can using the same input: vision.

Yes, and a sufficiently smart compiler should make optimization unnecessary. ;-)

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

#296

Post by snovv_crash »

01100011 wrote: post #69
snovv_crash wrote: post #25

Earlier quoted context omitted.

The amount of compute that sensor fusion uses is miniscule compared to running a NN or computing stereo depth maps. Sensor fusion runs in the background of your phone the whole time to power things like [0] for example. 0. https://sensor-js.xyz/demo.html

You are confused my friend. Reading sensor data is not the same as feeding that data to a neural network and asking it to form a worldview composed of possibly conflicting sensor data streams(i.e. lidar vs vision vs ultrasonic). You are somewhat correct that it is quite trivial to read sensor data. For many sensors, there is some work which needs to be done to denoise or cleanup the input data. That's not where the s…

In order to display the gravity-aligned acceleration, sensor fusion between gyro and accelerometer has to occur. This is typically done with a Kalman filter, and runs on 1960s levels of hardware. If you look at something like a drone autopilot, eg. Ardupilot, the sensor fusion is soo cheap that they even extended the Kalman filter to also estimate things like the sensor bias offsets and earth's magnetic field vectors.

Sensor fusion is computationally cheap. It's just a lot of R&D to do it in a way that leads to a net gain in precision and robustness.

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

#297

Post by ra7 »

ajross wrote: post #100
fzeroracer wrote: post #92

Earlier quoted context omitted.

> The LIDAR folks were wrong, basically. According to who? Tesla? Because Tesla has a vested interest in trying to prove that they're right even if they're obviously wrong. That's why they constantly try to downplay failures, software issues, device issues etc. I'm very confused by the attempts to discredit the usefulness of LIDAR. It's another tool you can use to improve the accuracy of your model. Sure, you can use…

The causality goes the other way. The LIDAR claim was that Tesla's vision approach couldn't work. It did.

Tesla’s vision approach doesn’t work. There is a reason it requires a driver to actively prevent crashes and has a disengagement rate in the single digit miles [1].

All over this thread you keep making grand statements that “it works”, which is just completely false. It’s simple — if it worked, there would be no driver.

[1] https://www.teslafsdtracker.com/

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

#298

Post by cbsmith »

Reason077 wrote: post #257
RC_ITR wrote: post #248

Earlier quoted context omitted.

So, yes, cars that are programmed to have AEB: perform well at AEB and not other tasks. We are in agreement here. (I even agree with you that those cars use Radar for AEB). Now, where we disagree is you implying that cars with AEB-level radar (literally $10 off-the-shelf parts with whatever sensor fusion some MobilEye intern dreams ups) are somehow the same as self-driving cars (the goal of Tesla Autopilot). Every se…

> ”There is no one sensor that will do it. Full stop.” Yet somehow, humans can drive cars with just a pair of optical sensors (mounted on a swivelling gimbal, of sorts). In theory, a sufficiently capable AI should be able to drive a car at least as well as a human can using the same input: vision.

> Yet somehow, humans can drive cars with just a pair of optical sensors (mounted on a swivelling gimbal, of sorts).

In fairness, humans have a lot more than just optical sensors at their disposal, and are pretty terrible drivers. We've added all kinds of safety features to cars and roads to try to compensate for their weaknesses, and it certainly helps, but they still make mistakes with alarming regularity, and they crash all the time.

When you have a human driver, conversations about safety and sensor information seem so straightforward. The idea of a car maker saving a buck by foregoing some tool or technology at the expense of safety is largely a non-starter.

What's weird is, with a computer driver, (which has unique advantages and disadvantages as compared to a human driver) the conversation is somehow entirely different.

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

#299

Post by vhold »

01100011 wrote: post #19

I still suspect it's because they need to preserve compute resources for vision processing. Sensor fusion is likely eating up too much of their current HW and limiting their progress in other areas. I suspect Tesla will have to admit they need to upgrade the current HW before they ever 'solve' FSD.

One camera produces millions of bytes of data every single frame, an ultrasonic sensor is useful producing just 1 or 2 bytes of data in the same time span. (distance to something within the sensor's cone).

So it seems like a totally ridiculous argument that ultrasonic sensors create some kind of data processing overload.

An ultrasonic sensor makes it possible to implement incredibly simple and reliable safety features with well known performance characteristics. Processing an image with ML to produce the same effect has tons of edge cases where it might not work, and nobody knows when it won't work, and every update to the system could introduce regressions.

It's why they had to disable certain features when they got rid of the ultrasonic sensors. Those features may come back some day, but I bet they'll never be as reliable, and certainly won't be as predictable.

https://www.pcmag.com/news/tesla-removes-ultrasonic-sensors-...

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

#300

Post by Animats »

From my DARPA Grand Challenge days, I used to have an Eaton VORAD automotive radar. This was an early design - 24GHZ, 1 scanning axis. It could see cars, but not bicycles, at least not reliably. For several months, I had one pointed out the window of my house, looking at an intersection. So I had a V-shaped wedge on screen, and could watch the cars go by.

It's a Doppler radar, so you don't get any info from things stationary relative to the radar, but you do get range and range rate. And the quality of that data is independent of distance. We used it mainly as a backup system for the world model built with LIDAR and (to a very limited extent) vision. The VORAD data could lower the speed limit for the rest of the system, and if a collision was about to happen, it would slam on the brakes independently of the world model.

The big problem with coarse automotive radar is that it can detect targets, but doesn't tell you much about them. Cars, trash cans, and metal road debris all look about the same. There's also a lot of trouble from big flat metal surfaces being mirrors for radar. We were willing to accept slowing down for ambiguous cases until the other sensors could get a good look. Drivers hate that if road-oriented systems do it.

Modern units are up around 70-80GHz and often have 2D scanning, which is a big help. I haven't seen the output from a modern automotive radar. I was expecting that by now, low cost millimeter microwave systems (200-300GHz) would be available, providing detailed images somewhat coarser than you can get with light. You get range and range rate, and you can usually steer the beam electronically rather than mechanically. The technology exists to get high-resolution radar images, but is mostly used for scanning people for weapons at checkpoints. It hasn't become cheap yet.

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