Lidars (Light Detection and Ranging) are similar to radars in that they operate by sending light pulses to the targets and calculate distances by measuring the received time. The key advantages of LIDAR is its superior accuracy and its ability to see through masking items, such as leaves, trees, and even camouflaged netting.
LiDAR has the advantages of creating high-resolution 3D images that identify the size, direction and velocity of objects in the field of view. Better yet, it works in all lighting and atmospheric conditions. And it’s hard to hack or fool. LIDAR systems have high accuracy due to its high spatial resolution due to the small focus diameter of the beam, as well as a higher pulse repetition rate. Since they use light pulses that have about 100,000 times smaller wavelength than radio waves used by radar, they have much higher resolution. That makes lidar better at detecting smaller objects and at figuring out whether an object on the side of the road is a pedestrian, a motorcycle, or a stray pile of garbage.
LIDARs are rapidly gaining maturity as very capable sensors for number of applications such as imaging through clouds, vegetation and camouflage, 3D mapping and terrain visualization, meteorology, navigation and obstacle avoidance for robotics as well as weapon guidance. LIDAR data is both high-resolution and high-accuracy, enabling improved battlefield visualization, mission planning and force protection. LIDAR provides a way to see urban areas in rich 3-D views that give tactical forces unprecedented awareness in urban environments.
Airborne LIDARs can calculate accurate three dimensional coordinates of both manmade and naturally occurring targets by combining the laser range, laser scan angle, laser position from GPS, and laser orientation from Inertial Navigation System. Additional information about the object, like its velocity or material composition, can also be determined by measuring certain properties of the reflected signal, such as the induced Doppler shift.
Grand View Research recently projected that the global LiDAR market will soar from $1.1B in 2018 to $2.9B in 2025, an almost 18-percent compound annual growth rate (CAGR). Inkwood Research predicts a 23-percent CAGR in roughly the same time period, noting that “the important driver increasing growth in the global LiDAR technology market is the demand for stronger security and sensor accuracy….LiDAR plays a significant role in homeland defense and national security and for an increasing number of applications which depend on timely, accurate geospatial data to support the decision-making process.” While the technology is indeed attractive and falling in price, LiDAR still remains a niche or high-security application because of the high cost of sensors compared to alternative technologies.
Wide applications of LIDAR in Security and disaster response
In terrestrial laser scanning applications, LiDAR is used to create a three-dimensional point cloud containing coordinate information from the entire details of an object. Hundreds of point clouds per square metre are produced from the scanned surface. These point clouds make it possible to produce accurate vector data for architecture and engineering projects.
LiDAR data can be used to obtain digital models of the earth’s surface, which can be used in land use planning to create detailed city models. What’s more, these large area models can be generated at relatively high speed, compared to other techniques.
Quanergy Systems, has introduced a new-generation product for measuring crowd size and customer footfall that can be deployed for the management of people and crowd flows in public areas. The company claims its Qortex People Counter solution can deliver 98 per cent detection accuracy, anonymously, under any lighting conditions – from pitch dark or indoor to very bright lighting conditions in full sunlight. “As sports stadiums, retail stores and public transportation move towards re-opening their doors and welcome back fans and shoppers, their ability to monitor and analyse crowd density and identify situations that will require immediate actions is paramount in the wake today’s Covid-19 pandemic,” said Enzo Signore, chief marketing officer at Quanergy. “The release of our new People Counter solution offers such a solution, incorporating LiDAR (light detection and ranging) and advanced perception software to provide accurate, actionable data for management of people and crowd flows in smart buildings and commercial retail locations.”
Aerial LiDAR has many applications, from infrastructure and civil engineering surveys to agriculture, forestry, mining and quarrying. LIDAR systems used to be heavy and were previously only operated from manned planes or helicopters. However, manufacturers have now started developing compact, lightweight versions. UAV LiDAR has been one of the most eagerly anticipated technologies of the last 10 years, changing the way surveyors capture data and significantly reducing costs.
With LiDAR technology you can take two types of elevation model: first return and ground. The first includes forest canopies and buildings (DSM), whereas the second contains only topography (DEM). As such, LiDAR can be used to create a detailed map of any given terrain, allowing scientists to study changes in slope and landform breaks.
Traditional methods of bridge inspection can be tricky and dangerous. Reliable inspection data is needed to make accurate performance predictions. LiDAR pulses can penetrate bridges to identify potential faults before, during and after construction. Due to its efficiency, LiDAR is now one of the cheapest and easiest ways to inspect bridges under development.
Using LiDAR sensors mounted on robotic vehicles, we can take surveys of high-risk areas that would be dangerous territory for humans – inside sewer systems, for example – while also simultaneously measuring airborne pollutants.
Traffic congestion, which causes environmental problems and accidents, is becoming increasingly acute. LiDAR sensors are used to monitor traffic congestion on roads and offer advice on alternative routes to be used. One of the goals of autonomous vehicles is reducing traffic congestion and pollution using these types of sensors.
LiDAR has proved invaluable to archeologists, helping them to plan field campaigns and observe patterns not visible from the ground. DEMs can also reveal micro-topography hidden by trees and shrubs. LiDAR data is easily integrated with modern geographic information systems (GIS) for further analysis.
Expert image processing and prodigious computer capacity can then yield models of bare terrain from which the vegetation has been digitally removed. In areas where dwellings, platforms, pyramids and even palaces can be obscured by high-canopy vegetation, a bare-terrain model yields something close to a topographic map of the surface. Straight lines and corners in a bare-terrain model suggest elements that have human rather than geological origins. Generating such models might not sound impressive for arid landscapes, but it is a game changer where high-canopy trees obscure the view. Lidar images from one plane flight can provide more information than can be generated by decades of conventional archaeological surveys. Lidar is changing archaeological study of the ancient Maya in Mexico and Central America. It is increasing the speed and scale of discovery, and reshaping our understanding of the antiquity of monumental-scale landscape alteration.
With its high resolution and accuracy, LiDAR can be used in the creation of maps. Its 3D capabilities make it particularly adept at mapping terrain models, such as mountain topography, as well as producing high-resolution contour maps.
One of the benefits of LiDAR is its ability to gather large amounts of high-resolution data in a short space of time. This makes it ideal for cellular network planning; determining the line of sight and viewshed for prospective cellular antenna – reducing costs in the process.
LiDAR scanning is an invaluable tool for creating Virtual 3D designs that can accurately represent buildings and interiors in vivid detail . Thanks to its efficiency, speed and accuracy, it’s becoming widely used in architecture, construction and design. Architects and designers can use LiDAR technology to create virtual 3D representations of the projects they want to build.
Mine operators have long used LiDAR to assist with planning and slope stability assessment. LiDAR can be used in mining to calculate ore volumes, penetrating the Earth’s surface to gather data on what lies beneath. Scanning of the areas is most commonly done with UAVs. But LiDAR has other uses in the mining industry: to determine what minerals lie beneath the surface of the earth, and in the analysis of mine structure to prevent them from collapsing.
Gesture recognition requires a fast response time. By measuring how far away an object is to the sensor, LiDAR can determine any object’s position in 3D space, measuring the distance a million times per second. This capability has automotive uses, for example, allowing the driver to use simple gestures to operate the vehicle’s infotainment system, as well as gaming uses.
LiDAR has a wide range of applications in the field of law enforcement, from speed limit enforcement to 3D recording of accidents and crime scenes. It can be mounted on a patrol vehicle or deployed via UAV. One of the most common uses of LiDAR technology in law enforcement is speed guns, which use laser pulses to calculate the exact speed of a passing vehicle and determine whether the driver is exceeding the limit.
Vehicle registration plates are an important part of traffic enforcement, and systems for automatic number plate recognition (ANPR) play a crucial role in many security applications. LiDAR technology is used for vehicle recognition and can reliably recognise license plates – even at high speeds and in heavy traffic. Facial recognition developer Digital Signal Corporation uses LiDAR to produce 3D facial scans at a distance, designed to improve security at airports. LiDAR can also be used in forensics, even so far as blood splatter analysis.
The analysis of dynamic 3D scenarios with multiple moving pedestrians has received great interest in various application fields, such as intelligent surveillance, video communication and augmented reality. In one study, a rotating multi-beam LiDAR sensor was used in gait analysis and activity recognition. In another, it was used for the motion estimation of vehicles, providing a complete strategy for urban traffic analysis using airborne LiDAR.
Scientists Are Using Laser Technology to “Fireproof” California
When it comes to wildfire, it’s largely about fuel. While the forests of the West were once subject to regular low-intensity fires that produced large, well-spaced trees and light accumulations of deadwood, more than a century of overzealous wildfire suppression and rising temperatures from climate change have reversed this dynamic. Combine the current dense, thicket-like stands of trees and piles of dead branches with hot, dry autumn winds, and the result is wildfires of devastating ferocity—wildfires like the 2017 North Bay fires and the 2018 Camp Fire in the town of Paradise.
The maps are produced through LiDAR, or Light Detection and Ranging, which is kind of like radar, except it uses pulsed lasers emitted from aircraft or satellites instead of radio waves. The process yields precise 3-D maps of the earth’s surface, detailing vegetation type and density. Researchers can look at a LiDAR map and evaluate “fuel ladders”—deadwood on the forest floor combined with the limbs and branches running from the ground to the tree tops—in any given stand of trees, down to resolutions of one centimeter.
“In conjunction with our partners at Pepperwood Preserve and Tukman Geospatial, we’ve created fuel loading maps from our LiDAR data that identify areas where heavy ladder fuels are located close to structures,” says Gaffney, who declined to comment on specific sites. “And because we can map development footprints down to resolutions of one centimeter, we can even identify risks for individual buildings.”
The maps are also being used to flag the best fire evacuation routes and the sites most susceptible to contamination or erosion post-fire. “For example, we can determine if a [burned] structure that contained toxic materials is at significant risk of contaminating a nearby stream,” Gaffney says. “While the maps first responders and firefighters typically use show all the major and secondary roads, our data let us create maps that show the much smaller routes that could also be used for evacuation.”
Research team develops first lidar-based method for measuring snowpack in mountain forests
Many Western communities rely on snow from mountain forests as a source of drinking water – but for scientists and water managers, accurately measuring mountain snowpack has long been problematic. Satellite imagery is useful for calculating snow cover across open meadows, but less effective in forested areas, where the tree canopy often obscures the view of conditions below.
Now, a new technique for measuring snow cover using a laser-based technology called lidar offers a solution, essentially allowing researchers to use lasers to “see through the trees” and accurately measure the snow that lies beneath the forest canopy. In a new study published in Remote Sensing of the Environment, an interdisciplinary team of researchers from Desert Research Institute (DRI), the University of Nevada, Reno (UNR), the California Institute of Technology’s Jet Propulsion Laboratory, and California State University described the first successful use of lidar to measure snow cover under forested canopy in the Sierra Nevada.
“Lidar data is gathered by laser pulses shot from a plane, some of which are able to pass light through the tree canopy right down to the snow surface and create a highly accurate three-dimensional map of the terrain underneath,” explained lead author Tihomir Kostadinov, Ph.D., of California State University San Marcos, who completed the research while working as a postdoctoral researcher at DRI. “Passive optical satellite imaging techniques, which are essentially photographs taken from space, don’t allow you to see through the trees like this. We are only starting to take full advantage of all the information in lidar.”
In this study, researchers worked with NASA’s Airborne Snow Observatory to collect lidar data at the University of California, Berkeley’s Sagehen Creek Field Station in the Sierra Nevada by aircraft on three dates during spring of 2016 when snow was present. Additional lidar data and ground measurements facilities by the long-term operation of Sagehen Creek field station were critical to the success of the study.
Analysis of the datasets revealed that the lidar was in fact capable of detecting snow presence or absence both under canopy and in open areas, so long as areas with low branches were removed from the analysis. On-the-ground measurements used distributed temperature sensing with fiber optic cables laid out on the forest floor to verify these findings.
Tree canopies interact with the snowpack in complex ways, causing different accumulation and disappearance rates under canopies as compared to open areas. With the ability to use lidar data to measure snow levels beneath trees, snow cover estimates used by scientists and resource managers can be made more accurate. The importance of this advance could be far reaching, said team member Rina Schumer, Ph.D., Assistant Vice President of Academic and Faculty Affairs at DRI.
“In the Sierra Nevada, April 1st snow cover is what is used to estimate water supply for the year,” Schumer said. “Being able to more accurately assess snow cover is important for California and Nevada, but also all mountainous areas where snowpack is essential to year-round water supply.”
Snow cover estimates are also used by hydrologists for streamflow forecasts and reservoir management. Snow cover data is important to ecologists and biologists for understanding animal migration, wildlife habitat, and forest health, and it is useful to the tourism and recreation industry for informing activities related to winter snow sports.
Although lidar data is currently collected via airplane and not easily accessible by all who might like to use it, the study team believes that information gleaned from this study could be used to correct data derived from satellite imagery, which is already widely available from NASA’s MODIS sensor and NASA/USGS’s Landsat satellites.
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