A thought about LIDAR

A LIDAR sensor fires a laser pulse. The pulse hits something. A tree. A person. A curb. A dog. The photon bounces back. The sensor measures how long the round trip took. From that time measurement, it calculates distance.

A self-driving car does this millions of times per second. Millions of tiny light pulses, bouncing off reality, returning as data points. Each point is a coordinate in three-dimensional space. Together, they form a cloud. A point cloud.

The car sees the world as a cloud of points.

Not as color. Not as shape, not the way we understand shape. As distance. As geometry. Every object in the world reduced to the time it takes light to bounce off it and come back.

There’s a poem in there somewhere. About perception. About how every mind, biological or silicon, builds a model of reality from the signals it can detect. We build ours from photons hitting our retinas. The car builds its from photons it sends out and gets back. Like echolocation, but with light.

The car’s world is made of echoes.

I think about that sometimes when a Waymo passes me on the street. The spinning sensor on the roof, firing invisible light in every direction, building a ghost version of the neighborhood from the reflections.

It sees me as a cloud of points. I see it as a car.

We’re both wrong about each other, probably.

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