Researchers have developed a new type of lidar system that can do much more than traditional versions.
In a single measurement, the new technology can determine where an object is, how fast it is moving, and what it is made of.
The advance could improve technologies such as self-driving cars, robots and remote sensing systems.
Lidar, short for “light detection and ranging,” works by sending out laser pulses and measuring how long they take to bounce back.
By doing this repeatedly, lidar creates highly detailed three-dimensional maps of the surrounding environment. Today, lidar is widely used in applications ranging from autonomous vehicles to mapping landscapes.
However, most commercial lidar systems focus mainly on measuring distance.
Some newer systems can also estimate an object’s speed, but they still struggle to identify what kind of material an object is made from.
Knowing whether an object is metal, plastic, vegetation or another material could help machines make better decisions and understand their surroundings more accurately.
The new lidar system was developed by researchers from the University of Toronto and the network technology company Ciena Corporation. Instead of building an entirely new device, the team adapted a piece of equipment already widely used in telecommunications: a coherent optical modem.
These modems are responsible for carrying internet data through fiber-optic networks across cities and even between continents. They are designed to measure and control light with exceptional speed and precision. The researchers realized that these same abilities could also solve many challenges faced by lidar systems.
In the new system, the optical modem acts as both the transmitter and receiver. It sends laser light toward a target and then analyzes the returning light. The laser beam is rapidly modulated billions of times every second and transmitted through two different polarization channels.
Polarization refers to the orientation of light waves. When light strikes an object, its polarization can change depending on the characteristics of the surface. By carefully measuring these changes, the researchers can obtain information that traditional lidar systems cannot provide.
The team also developed new computer algorithms to interpret the complex measurements. The returning signals are often distorted by noise and by the lidar system’s own internal optics. The new algorithms can separate useful information from these distortions and produce clean measurements of an object’s distance, speed and material properties.
In tests, the system successfully measured static and moving objects and performed better than existing methods, especially in situations where signals were weak or noisy. It also worked reliably under bright ambient light, which can interfere with other lidar technologies.
The researchers further demonstrated that the system could distinguish everyday materials such as metals and plastics and even detect differences in surface roughness. In addition, it could see through challenging environments containing fog, rain or dust.
Although the technology is still at the research stage, scientists believe it could one day help create safer autonomous vehicles, smarter robots and more reliable sensing systems that can better understand the world around them.
