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Has anyone been able to even remotely explain why the LIDAR system wasn't going nuts? I saw the "it was dark" nonsense, but I assume this vehicle had laser and IR right?

The camera footage was released, I'd like to see the lidar representation.




Author here :) LIDAR itself is just a sensor, it does not process the data nor does it output a directly usable image like a camera more or less does.

LIDAR in this case is a rotating laser and while it scans, the vehicle moves (imagine moving a paper when a copier scans it). All processing is done later, first to construct an image and then to understand and use it. Part of why I wrote the piece was to explain how things can go wrong even if your LIDAR works fine.


You don't have to "construct an image" to use LIDAR returns. Minimal processing on the point cloud will tell you that there's an obstacle, and you don't need more than that to start trying to avoid hitting it. A simple occupancy grid map, for instance, would suffice.

https://en.wikipedia.org/wiki/Occupancy_grid_mapping


The problem with naive occupancy grid mapping from sparse LIDAR data is that things like birds, falling leaves, pieces of paper of plastic bags flying in the wind can mark the grid occupied.

Emergency breaking for all these cases would be very dangerous. The same object must be scanned multiple times to get the idea if the object is something to be avoided.


Quite true -- but LIDAR has a very high refresh rate, and it's not hard to do better than naive grid mapping. This was a full height pedestrian plus bicycle, which would have multiple nice returns from a Velodyne HDL 64 at these distances.


Birds, plastic bags, cardboard boxes, small pieces of wood, and pieces of tires are perfectly good reasons to apply brakes and drive with caution to avoid.


and yet you wrote "now one of them thinks it’s a dog" as if sensors did image classification.


all kinds of things can learn to think things are dogs. you don't need an image


The closest I can give you is a simulation of a scene modeled after the video using a very simple reconstruction of the site of the accident (based on google maps and street view)

http://www.blensor.org/lidar_accident.html


The camera video seen publicly is from a dashcam, not the vehicle's own sensors. The NTSB has mentioned this.


A couple possibilities here. The LIDAR was turned off. Or the system just blatantly failed to categorize the pedestrian properly. Given that she was walking a bike that had bags on the handlebars this is my guess, the system just choked on that and was too stupid to brake for any object in the road that it might hit.


What makes you think it wasn't? You're making some assumptions about which of the many systems failed, I think.


You know what makes me thing the LIDAR wasn’t working, the part about the dead woman.


I thought there were suggestions that the LIDAR was turned off for testing.




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