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Camera vs. Lidar

scale.com

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Re: Camera vs. Lidar

#71

Post by mantap »

alkonaut wrote: post #58
pfundstein wrote: post #36

Earlier quoted context omitted.

Autonomous vehicles don't need to be perfect drivers -- from it, they just need to be better than humans.

No, we accept humans as being imperfect but we do not accept machines as being imperfect. Yes this means that companies that have autonomous vehicles that have a lower accident rate than humans may still be completely unable to sell them because of legal issues and market perception. We don’t know yet what the acceptance rate is for autonomous accidents - but I can guarantee it’s not the rational value of 1:1 or “as…

Yes and there's also a kind of lying with statistics that goes on. That human accident rate includes drunk drivers, very young drivers, very old drivers, etc.

The average accident rate is not your expected accident rate, if you are an average person who is not in those categories.

Re: Camera vs. Lidar

#72

Post by Animats »

Cruise Automation handling double-parked cars with LIDAR.[1] They show the scan lines and some of the path planning. Busy city streets, lots of obstacles.

Waymo handling city traffic with LIDAR.[2] They show the scan lines and some of the path planning. Busy city streets, lots of obstacles.

Tesla self-driving demo, April 2019.[3] They show their display which puts pictures of cars and trucks on screen. No difficult obstacles are encountered. Recorded in the Palo Alto hills and on I-280 on a very quiet day. The only time it does anything at all hard is when it has to make a left turn from I-280 south onto Page Mill, where the through traffic does not stop. [3] Look at the display. Where's the cross traffic info?

Tesla's 2016 self driving video [5] is now known to have been made by trying over and over until they got a successful run with no human intervention. The 2019 demo looks similar. Although Tesla said they would, they never actually let reporters ride in the cars in full self driving mode.

[1] http://gmauthority.com/blog/2019/06/how-cruise-self-driving-...

[2] https://www.youtube.com/watch?v=B8R148hFxPw

[3] https://www.youtube.com/watch?v=nfIelJYOygY

[4] https://youtu.be/nfIelJYOygY?t=353

[5] https://player.vimeo.com/video/188105076

Re: Camera vs. Lidar

#73

Post by donkeyd »

m3at wrote: post #37

It’s always better to have multiple sensor modalities available. This is the main takeaway. Unsurprising but interesting nonetheless. I'm working in the field and it confirms my experience. However they have a big bias that need to be pointed out: [...] we must be able to annotate this data at extremely high accuracy levels or the perception system’s performance will begin to regress. Since Scale has a suite of data…

> taking consecutive frames (2D images) we can estimate per pixel depth

Yeah, I find it odd that they're bringing up Elon's statement about LiDAR, but then completely ignore that they spoke about creating 3D models based on video. They even showed [0] how good of a 3d model they could create based on dat from their cameras. So they could just as well annotate in 3D.

0: https://youtu.be/Ucp0TTmvqOE?t=8217

Re: Camera vs. Lidar

#74

Post by semi-extrinsic »

ebg13 wrote: post #25
m3at wrote: post #24

Earlier quoted context omitted.

We don't just have 2D data though. We learn objects representations by interacting with them over years in a multi modal fashion. Take for example a simple drinking glass: we know its material properties (it is transparent, solid, can hold liquids), its typical position (stay on a tabletop, upright with the open side on top), its usage (grab it with a hand and bring to mouth)... We also make heavy use of the time dim…

You're not responding to what they said. The person you're responding to is talking about depth from stereo, not cognition. Lidar _also_ doesn't know what the glass feels like.

People who have good vision in one eye can usually get their drivers licence without problems. So the depth from stereo is not a necessary part of driving for humans.

Re: Camera vs. Lidar

#75

Post by nradov »

alkonaut wrote: post #64
nradov wrote: post #63

Earlier quoted context omitted.

How do you expect human remote control to work reliably enough for safety critical situations when our existing cellular data network fails so frequently? What happens when a construction crew accidentally cuts through the backhaul fiber?

The handover will be after the car stops because it’s confused. If there is no cell network or no operator available the car is simply stranded on the side of the road, just as after a mechanical failure. Operators can’t help “unknown situations” while moving.

In many places like bridges, hills, and congested city streets there is literally no road shoulder, no safe place to stop. When existing cars break down in those locations they end up blocking a traffic lane and frequently get hit from the rear by a drunk or distracted driver.

Re: Camera vs. Lidar

#76

Post by Symmetry »

donkeyd wrote: post #73
m3at wrote: post #37

It’s always better to have multiple sensor modalities available. This is the main takeaway. Unsurprising but interesting nonetheless. I'm working in the field and it confirms my experience. However they have a big bias that need to be pointed out: [...] we must be able to annotate this data at extremely high accuracy levels or the perception system’s performance will begin to regress. Since Scale has a suite of data…

> taking consecutive frames (2D images) we can estimate per pixel depth Yeah, I find it odd that they're bringing up Elon's statement about LiDAR, but then completely ignore that they spoke about creating 3D models based on video. They even showed [0] how good of a 3d model they could create based on dat from their cameras. So they could just as well annotate in 3D. 0: https://youtu.be/Ucp0TTmvqOE?t=8217

Egomotion is very useful but relies on being able to reliably extract features from objects which isn't always possible. Smooth, monochromatic walls do exist and it's imperative a car be able to avoid them. It is possible for a human to figure out (almost always) their shape and distance form visual cues but our brains are throwing far more computational horsepower at the task than even Tesla's new computer has available. But perhaps knowing when it doesn't know is sufficient for their purposes and probably an easier task.

An interesting intermediate case between a pure video system and a lidar is a structured light sensor like the Kinect. In those you project a pattern of features onto an object in infrared. Doesn't work so well in sunlight but be interested in learning if someone had ever tried to use that approach with ego motion.

Re: Camera vs. Lidar

#77

Post by ebg13 »

kajecounterhack wrote: post #61
ebg13 wrote: post #23

Earlier quoted context omitted.

> So the main problem is not just building the 3d models That's not relevant when discussing which technology to use to build the 3d models. Everything you said is accurate until the last few sentences. Lidar provide the same information (line of sight depth) as stereo cameras, just in a different way. The person you're responding to is talking about depth from stereo, not cognition.

> Lidar provide the same information (line of sight depth) as stereo cameras, just in a different way. This is incorrect, the amount of parallax you need to get the same kind of accurate depth using camera is infeasible. Velodynes other common lidar now gets you points accurate at 150m+. Cameras can't do that, and if you use nets to guess you'll still make mistakes. > The person you're responding to is talking about…

> the amount of parallax you need to get the same kind of accurate depth using camera is infeasible. Velodynes other common lidar now gets you points accurate at 150m+

I meant they both just provide line of sight depth.

The point being made by the first comment is that human eyeballs placed one inch apart are currently the gold standard for the actual looking part. So the right set of cameras is by definition sufficient for the looking part of driving. The cameras just have to replace eyes well enough. The brain replacement is farther down the chain.

Re: Camera vs. Lidar

#78

Post by Symmetry »

tgog wrote: post #3

This completely neglects the fact that humans can build near perfect 3D representations of the world with 2D images stitched together with the parallax neural nets in our brain. This blogpost briefly mentions it in one line as a throwaway and says you'd need extremely high resolution cameras?? Doesn't make sense at all. Two cameras of any resolution spaced a regular distance apart should be able to build a better par…

For human level driving a human level understanding of these scene from purely visual information is quite good enough. The first problem, though, is that the human brain has far more processing power than any computer that can fit in a car and probably more than any single computer yet constructed (estimating even to a single order of magnitude is hard). We're also leveraging millions of years of evolution though I'm not entirely sure how much of a difference that makes given how different our ancestral environment was from driving a car.

The other thing is that we, ideally, want a computer to drive a car better than a human can. There's a lot to be gained from having precise rather than approximate notions or other objects' distances and speeds in terms of driving both safely and efficiently. Now, Tesla has also got that Radar which when fused with visual data will help somewhat but I'm not sure how far that can get them.

Re: Camera vs. Lidar

#79

Post by Symmetry »

melling wrote: post #14
rmason wrote: post #10

I suspect this is yet another story sponsored by the Tesla shorts. Just saw an excellent two hour interview by Lex Fridman of George Hotz and he goes into details why he thinks camera will win over lidar. But he also admits that presently Google is ahead of everyone in the race for level 5, but raises the question of whether they can ever do it economically enough to make money on it? https://www.youtube.com/watch?v=…

I believe Tesla’s also have radar. I also listened to the podcast. George made it sound like the Lidar wasn’t being used for much. It augments the maps to help determine more precise location?

They have a fixed position radar which sees the distances and radial speeds of objects in a cone extending in front of the car. Because it can't tell you which direction an object is in they have to filter out objects that are radially stationary so as not to be triggered by things on the side of the road, overhead signs, etc. At least until these objects are close enough that the cone's width doesn't exceed the width of the car by much. Now, it's very useful when dealing with other moving cars which probably aren't hanging in the air above your direction of travel. But it doesn't help with everything.

Re: Camera vs. Lidar

#80

Post by Symmetry »

cameldrv wrote: post #33
melling wrote: post #14

Earlier quoted context omitted.

I believe Tesla’s also have radar. I also listened to the podcast. George made it sound like the Lidar wasn’t being used for much. It augments the maps to help determine more precise location?

I noticed that too. My understanding of what he said was most AV companies were using the lidar purely for localization (on an HD map) and not for object detection. This was the opposite of my understanding, so his statement was very confusing to me. Anyone able to comment?

You can absolutely use lidar pointclouds for object detection. It can be hard with low resolution lidar in a cluttered environment, though.
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