DM-PCSEL Lidar Captures 3D Information in a Flash — Ideal for Future Autonomous Vehicles

Researchers at Kyoto University, working with SpaceView Inc. and Brookman Technology Co., have come with with a non-mechanical lidar system capable of capturing 3D data in a single flash of light — and with which they're hoping to improve the safety of future autonomous vehicles.

"With our lidar system, robots and vehicles will be able to reliably and safely navigate dynamic environments without losing sight of poorly reflective objects such as black metallic cars," explains Susumu Noda, corresponding author on the work. "Incorporating this technology into cars, for example, would make autonomous driving safer."

The novel lidar device, which operates like radar but using reflected light rather than radio signals, uses a dually modulated photonic-crystal laser (DM-PCSEL) as its light source — meaning it doesn't need the physically-spinning mirrors common to most lidar systems and that makes them both bulky and provides a key point of failure.

"The DM-PCSEL integrates non-mechanical, electronically controlled beam scanning with flash illumination used in flash lidar to acquire a full 3D image with a single flash of light," Noda explains. "This unique source allows us to achieve both flash and scanning illumination without any moving parts or bulky external optical elements, such as lenses and diffractive optical elements."

Unlike traditional scanning lidar, which sends out narrow beams of laser light and measure the time-of-flight of its reflection to measure distances and build up a 3D image of its surroundings, flash lidar does it all at once with a single broad beam of diffuse light. The idea isn't new, but previous implementations have struggled with spotting objects which aren't so great at reflecting light — like black vehicles.

The DM-PCSEL lidar, by contrast, combines flash and beam-scanning approaches in order to work around the drawbacks of both. "Our DM-PCSEL-based 3D lidar system lets us range highly reflective and poorly reflective objects simultaneously," claims Noda. "The lasers, ToF camera and all associated components required to operate the system were assembled in a compact manner, resulting in a total system footprint that is smaller than a business card."

The team's work has been published in the journal Optica under open-access terms; its next step will be to demonstrate the practicality of the prototype in robot and autonomous vehicle applications, as well as to investigate a range extension using a single-photon avalanche photodiode array as the detector.