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Comment by sushisource | Hacker News Reader

Well, if you saw that video and it really did show a < 1 second time between the pedestrian becoming visible and being hit, then the autonomous systems don't matter at all. That accident is physically impossible to prevent in that car.

So whether or not the police understand self-driving systems is not relevant to the fundamental physics problem. The key question is how long was the ped visible.

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By the time that pedestrian has even traversed a single lane, the LIDAR on top has generated gigabytes of point cloud data showing her moving, assuming constant velocity of both car and ped, on a straightforward collision path.

I don't see how from a single forward-looking camera you want to deduce this crash was "physically impossible". That isn't even half of what we expect from human drivers. We expect them to swivel their head.

Where did I say just "camera"? By visible I mean visible in any way to the systems.

"The pedestrian becoming visible" would be to the video cameras. If the vehicle has other sensors (LIDAR, RADAR, etc), how sooner/later would the pedestrian be visible to these sensors? Would it be possible to judge that by looking solely at the dashcam? Would the sensors ignore the pedestrian as a false positive in these circumstances?

That's what I wonder. Yes, it has LIDAR etc. But there was this comment yesterday by arbie:[0]

> Sensor Fusion typically merges LiDAR with stereoscopic camera feeds, the latter requiring ambient light.

So might LIDAR data get de-emphasized when there's too little light for the cameras?

0) https://news.ycombinator.com/item?id=16619917

I don't understand that comment. "Sensor fusion" is the integration of data from two or more different sensors. It doesn't matter what those sensors are. They don't even have to be different types of sensors.

It may well be that the Uber cars only have LIDAR and optical, but that doesn't have anything to do with sensor fusion.

If there’s not enough light for the cameras, LIDAR would get emphasized, not de-emphasized.

Thanks. So in this case, how come the woman wasn't identified based on the LIDAR data?

No idea

I didn't mean just visible as in visible light visible - I mean detected in any way by the systems.

<1 second between becoming visible (on the left side of the vehicle) and being hit by the right side of the vehicle doesn't seem likely.

An accident may be physically impossible to prevent, but that's not the only standard. Initial reports (from the police) say that Uber AV did not even brake. Is not braking at all within a 1 second window the performance touted by AV's detection and braking system?

"ped"?

pedestrian

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