Robot Newspaper mobile mobile site, Kyoto University, Japan, developed a compact non-mechanical 3D lidar system

A research team at Kyoto University in Japan announced that it has developed a palm-sized, nonmechanical 3D lidar system.

According to the research team, it is the first product to combine the capabilities of a traditional beam scanning lidar system with the 3D approach of a flash lidar.

The Kyoto University research team published a research paper on the newly developed non-mechanical 3D lidar system in the specialized journal ‘OPtica’. The lidar system can measure the distance of low-reflective objects and automatically track their movements.

The research team said, “Robots and vehicles using the newly developed LIDAR system can move safely even in dynamic environments by recognizing objects with low reflectivity, such as black metallic cars, without missing them.” For example, if this technology is applied to self-driving cars, safer driving is possible.

This new lidar system employs a unique light source called a ‘dual modulated photonic-crystal laser’ (DM-PCSEL). Because this light source is made on a chip basis, it enables the development of on-chip all-solid-state 3D lidar systems.

The research team said, “The DM-PCSEL integrates non-mechanical electronically controlled beam scanning and a flash light source used in a flash lidar, so a complete 3D image can be obtained with a single flash.” In particular, it is explained that both flash and scanning illumination can be implemented without moving parts or bulky external optical elements (lens, diffractive optical element).

Typically, lidar systems illuminate an object with a laser beam, measure the time-of-flight (ToF) it takes for the reflected light to return, calculate the distance to the object, and map it. LiDAR systems are bulky and expensive because they rely on moving parts such as motors to scan the laser beam.

Adopting a non-mechanical approach, the flash lidar irradiates objects with a single, wide, dispersed beam and evaluates the distance to all objects. However, flash lidar systems cannot be used to measure the distance of low reflectivity objects such as black metal cars. In addition, the size of the external lenses and optical components required to generate the flash beam is generally large.

To solve these limitations, the Kyoto University research team developed a DM-PCSEL light source. The technology features both a flash source illuminating a wide 30°×30° field of view and a beam scanning source providing spot illumination with 100 narrow laser beams.

The research team integrated the DM-PCSEL into a 3D LiDAR system to measure the distance of many objects using the wide flash irradiation method, and at the same time selectively irradiate objects with low reflectance with concentrated beams. The research team installed a ToF camera for distance measurement and developed software that can automatically track the motion of objects with low reflectivity using beam scanning survey technology.

The research team plans to apply this technology to practical applications such as autonomous movement of robots or vehicles.