LIDAR may be more expensive, but it has one huge advantage: it can identify stationary objects in 3D space.

For a visual processing system to accomplish the same task, it must first: identify objects in a frame. Identify objects in the next frame. Identify objects in the images taken from the other cameras. Compare the objects, taking into account positional differences arising from the speed of the vehicle, and triangulate their positions relative to the vehicle.

This is certainly doable (Microsoft Photosynth has been around for at least a decade), but each one of these tasks, and especially the last task, requires more processing power than Tesla has put into its vehicles.

Interestingly, it can be done even with a single sensor. We can map object’s 3D positions with just one eye. The brain uses the relative motion of various object in the scene due to forward motion induced parallax and other clues such as object size. It’s possible to drive with one eye covered, but might as well use multiple sensors if available.

See “Depth Perception” at [1].

[1] https://en.m.wikipedia.org/wiki/Depth_perception

“One eye”, in humans, has about 125 million sensors (120 million rods, 6 million cones) Calling that “one sensor” is cheating slightly.

But yes, you only need that second eye for stereo vision if you only have data from a single moment in time.

In theory, you can see perfect 3D with a single photoreceptor by scanning with it (giving up temporal resolution, a bit like a electron gun that can write a million pixels per second writes only 50 or 60 images a second on a tv)

By your logic, a 125megapixel camera arguably has 125 million sensors too?

Assuming it’s a color camera, at least double that :-)

I have perfect vision in one eye and very poor vision in the other. While it's possible for me to drive without my glasses, I don't consider it safe. With one eye I can read signs, see pedestrians, cars, etc; but I find that the accuracy of my depth perception suffers. I estimate speed and distances with less precision. Try catching a baseball with one eye covered. It's possible but a lot harder.

Your brain is using something in the ballpark of a petaflop of computing power to do that sort of incredible stuff.

Motion is not required either. There's a reason for a shallow DoF in big photographic lenses/sensors. Bokeh can be represented as a processed depth map.