October 5, 2023

Lidar Demystified: Grasping the Fundamentals


What is lidar?

Lidar is an acronym for “light detection and ranging”. Some may call it radar’s cooler cousin – or maybe that’s just us. Instead of radio waves, it uses light waves to measure and localize objects in a much more accurate way. You can also think of it as a 3D camera, because of its ability to generate accurate, 3D representations of our environment.

The majority of lidar sensors we may encounter in our daily lives use infrared light, which falls outside of the visual spectrum. The lasers used are invisible to the human eye, causing minimal visual disruption. That’s why lidar sensors can be widely deployed, but you likely have not noticed their presence.

Despite its 60+ year history, lidar technology has come into the spotlight in recent years, revolutionizing mobility, enabling smart cities and transforming industrial applications. It helps cars and smart systems generate intelligent analytics of their surroundings in real time. In the In the same way that cameras and radars are integrated seamlessly in familiar spaces like our cars, lidars can be embedded consistent with existing design patterns.

Where is lidar being used?

Traditionally, lidar was used for weather and geological surveys. Those applications employ large lidar systems that command very high power and utilize platforms such as aircrafts to obtain 3D data. In recent decades, lidar started to appear in more places than you think. Your smartphone may even include a lidar sensor to enhance the camera’s depth-detection, or to enable 3D capture.

Lidar is poised to play an increasingly instrumental role in automotive safety and autonomy. Perhaps you’ve spotted a robotaxi – an autonomous vehicle (AV) that uses lidar data to navigate traffic. Before AVs become an everyday reality, lidar will transform your mobility experience by making driving safer for consumer vehicles.

Features in your car that assist your driving, such as adaptive cruise control or lane keeping, are part of the vehicle’s advanced driver assistance system, or ADAS. Top global automakers are competing to add lidar to ADAS to significantly improve the system’s accuracy and expand its capabilities, so that you and your family will feel safer in the car, 24/7. We’ll explain later in this blog post.

Besides our vehicles, lidar is also deployed in smart cities, robotics, security, crowd management and even spacecrafts. Without knowing, you may have already benefited from Cepton’s lidar technology at airports like MCO, on tollways in the Tri-State area and Northern California, or at traffic intersections in Texas. In the context of smart infrastructure applications, lidar has many unique advantages over camera – find out here.

Autonomous driving is not happening soon – why do we still need lidars in cars?

At Cepton, we believe lidar is first and foremost a safety device.

In safety-critical applications like ADAS, redundancy of the environmental sensing system is vital, and lidar adds a critical layer of certainty by filling the gaps in distance measurement. This ensures higher dependability in the system’s planning and decision functions across different environments.

ADAS platforms without lidar might be able to cover many driving scenarios, but the lack of accuracy makes them far from being error-proof. While you might think an improvement from 99% to 99.99% in efficacy and reliability is negligible, when it translates into the likelihood of risk, the leap is huge. That is a drop from 1/100 to 1/10,000 chance of getting into an accident!

The consumer appetite for higher levels of safety may never be satisfied. More consumers are interested in seeing current vehicle safety systems improve than having more automated features – here’s a deeper discussion on that.

Lidar is a future-proof technology. Integrating lidar into automotive sensor suites in today's consumer vehicles can help lay the groundwork for more advanced autonomous features down the road, simplifying the transition to higher automation levels as technology evolves and regulations change.

In what driving scenarios is lidar most helpful?

The benefits of lidar shines in nighttime driving scenarios. Human eyes and cameras rely on external lighting sources, but streetlights and headlights have limited range and intensity. Sending out invisible lasers, lidar serves as its own source of illumination to proactively detect things in darkness – be it a small black dog in your neighborhood, or a big brown bear on an alpine highway.

Lidar also helps in many daytime driving scenarios, as too much light can be just as dangerous as low light. Cameras struggle with blinding sunlight, making the ADAS unable to “see” obstacles and lane markings. Likewise, transitions in lighting conditions when entering or exiting tunnels affect camera performance, leaving the vehicle's perception system vulnerable.

Lidar also proves invaluable for precise 3D sensing. For example, it calculates safe distances behind trucks with tailgates down, a task camera struggles with. It distinguishes actual objects from graphics printed on buses or billboards. Mr. Elon Musk’s stop sign T-shirt has tricked Autopilot, but it can’t fool a lidar sensor. Learn more here.

However, like any other technology, lidar doesn’t guarantee safety in all driving scenarios. It is always a good idea to avoid driving in extreme weather conditions. Our mission is to industrialize lidar, but our commitment is to see you safe.

Are lidars safe for the human eye?

To answer this frequently asked question simply, lidars need to be eye-safe when used in cars and smart infrastructure. Proper optical design is crucial for ensuring eye safety, which depends on factors such as laser wavelength, exposure time, peak power, repetition rate, and more.

The best way to confirm if a lidar is eye-safe is to check for the eye safety certification from its supplier. Based on requirements from our automotive OEM customers and system integration partners, we have optimized Cepton lidars’ optical parameters to achieve Class 1 eye-safety, the safest tier of the Laser Hazard Classification, as defined by The Laser Institute of America.

Class 1 eye-safe lasers are considered incapable of causing eye damage under normal operating conditions. To put things in perspective, sunlight is also considered Class 1 eye-safe.

However, it might not be the best idea to engage in a staring contest with an operating lidar sensor. Think of it as gazing at the sun – minus the sneezing part!