3-D images with only one photon per pixel

A new scheme could enable laser rangefinders to infer depth from a hundredth as much light, and to produce images from only one nine-hundredth the light.

Lidar rangefinders, which are common tools in surveying and in autonomous-vehicle control, among other applications, gauge depth by emitting short bursts of laser light and measuring the time it takes for reflected photons to arrive back and be detected.