In the late years, lidar (light detection and ranging) has advanced from a useful measurement for studies and research of aerosols and aerial mapping towards some kind of a new Holy Grail in opt mechanically and opt electrical engineering. World-renowned engineering companies are initiating startups and are receiving relevant support in terms of investment from venture capital sectors. Besides, some companies that had established themselves in the sector are now being acquired by advanced firms mainly from the automotive industry. The fuel of all this is inadequacy in every aspect for lidar imaging for the automobile due to lack of components or cost issues. This has prompted one of the strongest market-pull in the autonomous industries. All said and done, lidar technology works by illuminating a target with an optical pulse and determines the features of the reflected return signals. This article intends to neutrally introduce the fundamental aspects of lidar and various place of its application. Check out!
What is automotive lidar?
Lidar sometimes called laser scanners, or laser radar is a detecting technique that senses objects and maps their distances. The system was developed in the 60s just after the invention of the laser. It works by measuring the distance by illuminating a target with a surge laser beam and determining the bounced pulse’s return.
Detecting and imaging of autonomous vehicles
Manufacturers are equipping modern cars with a variety of array of advanced control and detecting roles. Collision warning and prevention systems, blind-spot monitors, lane-keepers and adaptive cruise are the leading examples of the established features that help drivers and automate some driving tasks, making driving safe.
Lidar and cameras have their own set of weaknesses and strengths. Entirely driverless cars use multiple sensors systems to provide an exact long and short-range map of vehicles surrounding under a range of weather conditions. Besides the technology complementing each other, it’s also essential to have enough overlap to raise redundancy and improve safety.
Cameras are not that costly and are readily available sensors; however, they require significant processing to get useful information and rely strongly on the ambient light conditions. Nevertheless, cameras are unique in that they’re the only systems that can view colour.
Where automotive lidar now and where is is it heading
There’re two automotive applications for lidar. The first is for advancing fully driverless vehicles, for instance, SAE level 4 and 5 systems. The other one which is really attracting so many interests is the ADAS (advanced driver assist systems). This system initially played a significant role like emergency braking, blind-spot protection, and lane-keeping assist; they’re heading towards advanced features such as highway autopilot and some limited set of self-driving characteristics. As a result of technology development, autonomous vehicles are going to fleet markets from small to fleets of tens of cars to thousands in the next few years, thus increasing the improvised detecting technologies’ requirement. Lidar is growing increasingly sophisticated and will be a principal associate in autonomous sensing along with cameras and radar.
What lidar can do that cameras and radar cant?
As discussed, cameras are relatively inexpensive and have a higher resolution power. However, they have a passive detecting technology. Besides, since they are sensitive to ambient light, they fail to perform uniformly has needed for the changing conditions. So, due to limited performance, you likely to get a lot of variability in the results.
Lidar is a unique technology since it sits between the two sensor modalities. Since it’s a light-based system, it a high resolution than cameras and radar and view reflectivity, colour and lane markings. Therefore, it capable of sensing a similar context just like a camera, but because it brings its own light to the party, it’s not a detective to ambient light conditions. Actually, it works the same way whether it’s during the day or at night.
Also, lidar is direct rather than an extract measurement of distance. It releases a laser pulse and determines accurately when the pulse returns. Since the speed of the surge is constant, this is a direct and active measurement. Besides, its resolution is only restricted by the wavelength of the light being consumed, which is close to infrared in automotive lidar. This implies that you can resolve the interval in the range of a millimetre or two.
Environmental sweeping
For lidar to be essential in self-driving vehicles, it has to sweep the surrounding to generate a useable 3D map. For instance, Velodyne has two different systems for that. One of them is their surround-view which attains a 360 degrees view around the detector using a solid-state electric lidar engine which is significantly rotated on the spindle.
The other one is a small form factor implantable lidar referred to as Vellaray which uses frictionless steering beam that can be swept in two axes. Because it’s not physical rotated yet, its field of view is limited to 120 degrees.
Software
As the autonomous vehicle’s speed increases, the code of preparing the unit inside this system, which is the pretty big computer at the moment, really has precious little time to consume all the information and make decisions. As a result, a tremendous amount of the processing will be done in the sensor itself. Instead of generating raw data, the future analytics implanted in a lidar will directly give the location information.
Sensing the environment
The current lidar technology resolution is enough to differentiate between many objects, for example, a pedestrian and a bicycle. Apart from a distance, lidar systems can also examine the bouncing back of an object. Usually, stops signs are high, and the word “stop” is in the white, and the background is in red. Hence the system cannot just sense the presence of a sign, but the virtue of the reflectivity to determine its nature. Also, lane markings are reflective than the road surface and so on.
This instance allows lidar to generate a view of the world independent cameras and radar, though there will probably not be any attempt to challenge them. Likely, there will be a need for redundant detector modality as support just in case the lidar systems experience challenges to ensure that the vehicle can safely move itself to a safe stop.
Application of lidar technologies
- Agriculture
Lidar systems can be used to create a 3D elevation map of specific land. This scan can be converted to provide a slope and sunlight exposure. Moreover, this information can identify areas that need more fertilizer and help farmers save on labour time and money.
- Autonomous vehicle
If you have seen a driverless car before, you’ve probably seen a lidar sensor. It operates as an eye of the autonomous vehicle. Figure out if your eyes allowed you to see in all direction every time. Can you imagine if, rather than guessing, you could always know the precise distance of objects? Lidar enhances a driverless car to see the surroundings with special powers.
- River surveys
Water piercing the green light of lidar can view things underwater and create a 3D model of the land. Creatures found deep in the water of a river can help comprehend the water’s depth, width, and flow. Also, it’s essential in monitoring the floodplains.
- Modelling pollution
Lidar wavelength is shorter. It works in ultraviolet, visible region or near-infrared. This is necessary to image the matter which is either of the same size or larger than the wavelength. So then, lidar can detect carbon pollutants particles, Sulphur dioxide and methane. Therefore, this info is vital for researchers to create a pollutant density map of the area used for the city’s proper organization.
- Archaeology and construction
Lidar technology plays a significant role for the archaeologist to comprehend the surface. Besides, it can sense micro-topography covered by vegetation, thus helping the archaeologist understand the surface.
Underground lidar systems are essential for capturing the structure of the building. This current information can be used for 3D mapping because they’re vital in providing structure models. It is also significant for keeping a record of the structure.
My final thought
Automotive lidar is emerging as one of the most breathtaking photonic applications in recent history, with the capability of positively affecting millions of lives yearly. Early deployments reveal the technology promise while also stating the challenges that lie ahead of the interns of range, object detection and cost. Besides, imaging systems are one of the hottest topics in optronics companies currently. The agency of sensing the surrounding on each driverless car has pushed forward a competition dedicated to deciding the final solution to be implemented. Nevertheless, the diversity of the state of arts approaches to the resolution results in considerable uncertainty on the final decision’s decision. These systems are also enhanced agricultural activities, construction, modelling and among others.
