The many applications of LIDAR

This article originally appeared in the November '21 magazine issue of Electronic Specifier Design – see ES's Magazine Archives for more featured publications.

Many applications and industries have adopted LIDAR technology: the applications range from geographical surveying to 3D structural mapping and object recognition. Industries include manufacturing automation, safety, agriculture, and many others. Tony Pirc, Applications Engineer at Analog Devices discusses the many applications that LIDAR accommodates and more.

All the above-mentioned applications and industries have leveraged LIDAR to drive down costs, create safer environments, improve efficiencies, or even achieve technological feats that were not previously thought possible. To better understand the impact of LIDAR, it is important to understand what this technology is, what was used before it, and what LIDAR allows us to measure and – more importantly – do.

At the most fundamental level, LIDAR is a system that bounces light off objects to detect them. This boils down to a transmitting portion of the system that emits light, and a receiving portion that measures the reflected light’s time of return. This happens to be exactly how traditional radar systems work, with one very important difference: the wavelength of LIDAR systems is on the order of ten thousand times shorter than the shortest radar wavelengths.

What is different with LIDAR?

What does a much shorter wavelength enable us to do that we could not do with radar? A shorter wavelength allows us to see a much higher resolution image, due to a physical limitation that a measurement cannot be more precise than what is used to measure it. Even with tricks in software and signal processing, you can only characterise something so well if you are using long wavelengths to do it. With LIDAR’s shorter wavelength, you can scan the environment for objects and their features, instead of being limited to only knowing location, rough size, and velocity.

Imagine trying to navigate an unfamiliar dark room. You generally move more slowly than when it is illuminated, and you would use your hands to feel around for objects to get a sense of what is where. Take that same scenario and put on a pair of latex gloves, gardening gloves, or boxing gloves. Each of those pairs of gloves have value in their own applications, but not so much when trying to navigate in the dark.

What a human sees versus what a radar sees

Hasn’t LIDAR been around for decades? What is new?

Radar has been used very successfully for many decades and will continue to be invaluable, but now we have an additional tool coming up on the horizon that will allow us to further extend our ability to sense things. Until now, LIDAR has been restricted to applications that are large and expensive (like specialised surveying equipment) or smaller and simpler (like speed detection devices used by law enforcement).

A high-performance LIDAR system must meet certain criteria. The transmitting portion, for example, needs to pulse the laser for 3 nanoseconds (ns) to 5ns at a peak of 40A to 80A to make it attractive for automotive. Laser drivers are finally approaching these metrics of interest, making this portion of LIDAR a reality. Other factors include small and efficient power management, the integration of subsystems, inexpensive high-speed data processing, and sophisticated software to make sense of all the data.

Our ability to push LIDAR systems’ performance up and power budget down is nearing the point where it makes sense to use the technology in many applications where they simply could not meet demands previously. Due to this approaching critical mass, the collective effort in driving down the cost, size, and power needs while increasing performance is accelerating the attraction to this solution.

Like the microelectromechanical systems (MEMS) revolution of the 1990s, LIDAR today is becoming smaller, cheaper, and more versatile. Both LIDAR and MEMS took a long time to fully realise their potential within other systems and subsystems. MEMS, while developed in the 1950s, was never a practical option to integrate into many systems due to its cost, size, power needs, and performance.

It was not until process technology in the 1990s became mature enough to match demand that it was then able to allow proliferation of MEMS into applications never dreamed of before. Similarly, LIDAR (developed in the early 1960s) is only now ready to meet similar demands.

What is currently changing is the confluence of factors that goes into the design and manufacture of a high-performance LIDAR system. These additional factors have helped LIDAR to meet the constraints inherent in it, such as driving down cost, solving size and power issues, and increasing overall performance. Because these factors have helped LIDAR technology with enhanced performance while decreasing development costs, it makes sense to begin pursuit of other areas for LIDAR application.

Leaps in development of LIDAR and MEMS technology over 13 years

What is LIDAR allowing us to do that we have not done before?

Imagine what sorts of novel technologies can be developed with a system that can scan surfaces when it is within a much more attainable price point. Here are a few recent innovations to the application of LIDAR systems

Entertainment

The ability to map out complex sets or objects digitally has proved a boon in the entertainment industry: it allows for a more seamless interaction between reality as we know it and realities generated by software. In movies or video games, for example, this allows for fluid 3D motion capture by human actors transcribed into a fictional universe that, until now, relied on expensive suits with sensors (which conveyed limited movement information) or homebrew animation (which, depending on detail desired, can be slow and expensive).

Geographical survey

LIDAR has been used in geographical surveying for some time, but the increase in range and resolution of these systems has allowed researchers to uncover ancient ruins that would not be feasible to investigate by foot. The constantly decreasing size and cost is also making the technology much more attractive for civil land surveying and engineering, with advantages over traditional land surveying methods in speed, accuracy, flexibility, and safety.

Structural and civil engineering

As a building is being constructed, LIDAR can be used to monitor construction progress in real time, compare those measurements to current schematics, and allow for the updating of those schematics. Existing structures can also be scanned to better understand the evolution of integrity over time, which would allow users to more appropriately assess the needs to renovate or rebuild.

3D motion capture of Yesteryear using speicla sensor-based suits

Transportation

The panacea of autonomous driving is the addition of a low-cost LIDAR system to complement the suite of instruments that currently measures the surroundings of a vehicle. LIDAR signals allow the autonomous system to gauge the detailed surface features (thereby object identifying) that radar cannot – and cut through weather obstructions much better than a traditional vision system.

Safety

Outfitting what were traditionally simple ‘Is there something in front of me?’ sensors with LIDAR systems can have the benefit of knowing how and when to respond in safety situations. A robotic arm that handles heavy objects will be able to respond more keenly when a person-like object enters its path, as opposed to an object that it was designed to handle

Agriculture

Simple sensors have been used for years to detect things like the level of grain in a silo, the state of crops, fuel level, and so on. What these methods often do not capture is that the deeper context – like how the shape of the mound that the grain makes when poured into the silo and where it is measured (highest, lowest, mean, or arbitrary point) – can affect how efficiently the storage is being utilised.Currently, the only way to capture this information using traditional methods is by using multiple sensors, which itself has resolution limits while adding significant cost to manufacturing. Being able to capture a whole crop’s growth in granular detail over time provides important data and can inform cultivation practices, both in real time and for future crops. LIDAR can also help optimise the movement of automated machinery in harvesting crops.

Automation

Knowing the physical structure in precise detail adds tremendous value to robotics, which can more accurately and appropriately handle objects of various sizes and geometries. This can be extrapolated to any manufacturing or warehouse context that involves repetitive handling or sorting. Having this additional information can also allow for the relaxation of otherwise unnecessarily tight tolerances in manufacturing, therefore saving costs in production and quality control.

Real-time updating of a construction site, informing changes needed in design

A car detecting features of proixmal objects at night, allowing for the sale operation of the vehicle

Exploring further potential of LIDAR

The previously discussed applications are ones that are currently being, or have already been, developed. As is always the case in human endeavors, it is impossible to know what other creative and useful applications people will invent to use technology such as LIDAR. If you have a product or system that may be able to leverage the benefits of LIDAR, Analog Devices has the expertise to help you along the journey from conception through creation to make that idea reality.

With LIDAR, damage and defects can be detected before bottling where it often is not practical to set yp a large vision system