LiDAR, which stands for light detection and ranging, is a technology that allows intelligent machines to sense and assess their surroundings using laser pulses. LiDAR sensors can calculate everything from an object’s position to its shape, size, direction, speed of travel and material makeup. This technology often goes hand in hand with autonomous robots and self-driving cars.
LiDAR Definition
LiDAR, an acronym for ‘light detection and ranging,’ is a remote sensing technology that emits continuous laser pulses to calculate the position of objects in the surrounding environment.
What Is LiDAR ?
LiDAR is a remote sensing technology that uses a pulsed, modulating laser to measure distances. In the time it takes for these pulses to reflect off of targeted surface areas, these systems can track changes in and create high-resolution digital 3D models and maps of their environment from collected data points.
“LiDAR sensors give intelligent systems 3D vision of the world around them,” Mark Frichtl, co-founder and chief technology officer at global LiDAR tech company Ouster, told Built In.
There are three categories of LiDAR systems: ground, airborne and mobile. Each generally features the following essential components: a laser source, scanner, detector and processor as well as an inertial measurement unit and GPS unit.
Compared to other sensing technologies — like radar, photogrammetry or sonar — LiDAR uses narrow beams of light at shorter wavelengths to collect spatial data “within millimeters of accuracy” and “up to 200 hundred meters away,” Frichtl said.
This results in highly accurate, detail-rich data sets that, in addition to generating digital maps and models, can track, count and classify objects over time and gather insight of activity in its immediate surroundings, such as traffic patterns and human behavior.
How Does LiDAR Work?
LiDAR works by emitting laser pulses from a sensor toward a target area, with each pulse hitting objects or surfaces that reflect back to the sensor. The time it takes for the pulses to return is measured, allowing the system to precisely calculate the distance to each object.
“Since the speed of light is constant, this time can be directly converted into distance,” Rugved Hattekar, a LiDAR software developer of machine vision systems at Luminar Technologies, told Built In.
By emitting millions of these pulses per second across multiple streams — measuring both the distance and angle of each laser — LiDAR collects a high volume of data points that accumulate into dense ‘point clouds.’ Each of these data sets contain the coordinates of surrounding objects, including a target’s exact position, shape, size and even its texture.
These calculations are then analyzed in real time or processed across various software applications to generate detail-rich 3D maps or models of a dynamic environment.
LiDAR systems typically use a LiDAR scanner supplemented with other sensing devices, like cameras, radar and GPS navigation systems. So where one sensor type fails or experiences latency issues, another can compensate. This is seen in self-driving vehicles that need to make quick decisions relative to their immediate (and often unpredictable) surroundings, Tobias Wessels, the chief development officer at AI software startup for autonomous and advanced driver-assistance systems Helm.ai, explained.
“LiDAR significantly improves decision-making capabilities,” Wessels said. “Rich sensory input from multiple sensors is crucial for ensuring safety and reliability in various driving scenarios, like heavy fog or poorly lit roadways, where cameras alone might struggle.”
Uses Cases for LiDAR
LiDAR’s ability to rapidly produce high-resolution 3D maps in ever-changing environments has lead to a variety of applications, including the following.
Self-Driving Cars
LiDAR allows self-driving cars to detect, classify and avoid obstacles with real-time 3D mapping. With a continuous feedback loop of its surroundings, self-driving cars apply this information to create an artificial sense of awareness that helps them maintain their position on the road, adhere to traffic rules, keep a safe driving distance and react to dynamic roadside scenarios.
Land Surveying and Topographic Mapping
Modern airplanes, drones and helicopters use LiDAR sensors to capture geospatial data. This allows them to digitally recreate accurate terrain and elevation models, scanning thousands of acres in one flyover. LiDAR can pulse underwater too. The National Oceanic and Atmospheric Association uses water-penetrating frequencies to map riverbeds and shallow coastal bodies.
Urban Planning
When mapping out a cityscape, LiDAR collects data that city planners use to transform concepts into creation. Precise 3D models of buildings, roads, bridges and existing infrastructure use virtual simulation to trial designs and assess the impact of new developments, such as traffic flow or preserving local historic sites.
Forestry
Foresters use LiDAR when taking inventory — measuring tree height, canopy structure and diameter — and conducting canopy analysis, which provide insight into the health and productivity of a forest. It also helps researchers identify wildlife habitats for biodiversity studies and monitor changes in forest structure over time.
Agriculture
Agricultural organizations benefit from LiDAR as not only a highly accurate mode of data capture, but also a noninvasive one. When mapping landscapes, topographical features and structural characteristics of trees, these systems collect data points that can be used to estimate crop biomass and detect soil properties.
Spaceflight
LiDAR has been in space since 1971. It was first deployed on the Apollo 15 mission as a laser ranger, which collected thousands of lunar surface measurements. Today, space-based LiDAR is used to determine the location, distribution and nature of particles in atmospheric studies and create digital elevation maps of planets. It also helps navigate celestial terrain.
Disaster Management
LiDAR is a valuable tool in that it can assist in both disaster prevention and recovery. City planners and emergency responders alike rely on LiDAR-captured data when navigating risks and evacuation routes. For example, the Federal Emergency Management Agency uses LiDAR to create floodplain maps, along with the U.S. Geological Survey to manage water resources, monitor earthquakes and volcanoes and identify landslide-prone areas.
Benefits of LiDAR
There’s a number of reasons why LiDAR has found a way into so many industries.
Precision
LiDAR works off of a constant feedback loop of pulsating lasers that report millions of data points per second. Using narrow lasers, these sensors have a range accuracy between 0.5 and 10 millimeters and a mapping accuracy under two centimeters, according to navigation systems manufacturer VectorNav.
Speed
LiDAR uses the fastest-traveling agent known to man — light — to rapidly scan and collect data. It then multiplies the number of high-frequency laser channels at constant emission, delivering accelerated performance that outpaces traditional surveying methods.
High Resolution
As emitted light beams bounce back from their target, they collect massive amounts of spatial data points. These ‘point clouds’ represent the surface characteristics of its subject, and are used to create digital 3D models and visualizations in exceptional detail, like a pixel would an image.
Versatile
There are three main types of LiDAR platforms: airborne, terrestrial and mobile systems that attach to various vehicles. LiDAR systems have also found their way into space, as terrain-navigating helicopters and earth-sensing satellites.
Enhanced Safety
LiDAR is both autonomous and remote. In other words, there is little to no human intervention involved in the process. By collecting data from a distance, LiDAR systems have eliminated in-field personnel from potentially hazardous environments, such as volcanoes, mines and disaster zones.
Challenges of LiDAR
Not everyone is a fan of this emerging technology, due to the following drawbacks.
High Cost
Upfront costs for LiDAR systems — inclusive of sensors, software and a platform-of-choice — are not cheap. And given the high-volume of data sets they collect, neither are the operational costs. That said, due to the increasing production of self-driving cars, companies are working on commodifying LiDAR tech, which results in prices dropping every year. In fact, Mad Nadir Mapping released a LiDAR system for $5,000, claiming to be the lightest and most affordable on the market.
Interference
A LiDAR system’s performance can be adversely affected by weather conditions enough to limit its usage based on the climate or time of year. Rain, fog, snow and dense clouds can scatter or absorb emitted laser pulses, which reduces the accuracy and range of lidar measurements and ultimately distorts its visualized surroundings. “Such limitations could lead to safety risks for drivers and pedestrians without proper human oversight,” Wessels said.
Data Overload
Many argue that there’s too much data generated by these systems. The more data, the more storage and processing power is required. This is why many companies subcontract data management to specialty firms that are equipped and technically talented to handle such high-volume data sets.
Frequently Asked Questions
What is LiDAR used for?
LiDAR is used to detect objects and examine environments with accuracy. It’s commonly used to create high-resolution topographic maps and 3D models of buildings and infrastructure.
What does LiDAR stand for?
LiDAR is an acronym for ‘light detection and ranging.’
What does LiDAR do on cars?
LiDAR allows self-driving cars to “visualize” their environment. Using a constant feedback loop of laser pulses, these systems create 3D maps of the vehicle’s dynamic environment to measure its distance from surrounding objects, such as other cars, pedestrians, cyclists and road signs.
