Lidar is a surveying method that measures distance to a target by illuminating the target with laser light and measuring the reflected light with a sensor. Differences in laser return times and wavelengths can then be used to make digital 3-D representations of the target. The name lidar, now used as an acronym of light detection and ranging (sometimes, light imaging, detection, and ranging), was originally a portmanteau of light and radar. Lidar sometimes is called 3D laser scanning, a special combination of a 3D scanning and laser scanning. It has terrestrial, airborne, and mobile applications.
Lidar is commonly used to make high-resolution maps, with applications in geodesy , geomatics , archaeology, geography, geology, geomorphology, seismology, forestry, atmospheric physics, laser guidance, airborne laser swath mapping (ALSM), and laser altimetry. The technology is also used in control and navigation for some autonomous cars.
Working of LiDAR Technology :
LiDAR works in a similar manner as radar and sonar works, but it uses light waves from a laser. Generally, a LiDAR device consists of a laser, a scanner, and a specialized GPS receiver. From the LiDAR system, light is emitted from a rapidly firing laser. The sensor on the system calculates the total time taken for each pulse to bounce back. Since the light moves at a constant speed the LiDAR device can calculate the distance between itself and the target. The GPS is used for identifying the X, Y, Z location of the light energy. By repeating the same process, it forms a map of the surface it is measuring and the 3D model of the surface can be constructed.
How is LIDAR data collected?
When an airborne laser is pointed at a targeted area on the ground, the beam of light is reflected by the surface it encounters. A sensor records this reflected light to measure a range. When laser ranges are combined with position and orientation data generated from integrated GPS and Inertial Measurement Unit systems, scan angles, and calibration data, the result is a dense, detail-rich group of elevation points, called a “point cloud.”
Each point in the point cloud has three-dimensional spatial coordinates (latitude, longitude, and height) that correspond to a particular point on the Earth’s surface from which a laser pulse was reflected. The point clouds are used to generate other geospatial products, such as digital elevation models, canopy models, building models, and contours.
Implications/uses of LIDAR in our lives:
Human beings are peculiar creatures who want to know anything and everything. In order to do this, we have developed many technologies and devices so that we can search and gather about the unknown. LiDAR stands for Light Detection and Ranging, is a remote sensing method that measures the distance to a target by illuminating the target with pulsed laser light and measuring the reflected pulses with a sensor. LiDAR is one of those technologies, which helped scientists and researchers to characterize vegetation and other objects across large sections. To map objects, LiDAR uses ultraviolet, visible, or near-infrared light. This remote sensing method is used to make geological maps, create virtual models of city landscapes, scan the ocean floor at some shallower depths, and map changes happening in coastlines.
1]Vehicle Automation:“LIDAR is becoming more popular in vehicles to make it automatic. LIDAR is used to grab the information on the road and it is passed to computerized system to make a human being like decision. For example, LIDAR can detect the road yellow lines which tell the vehicle to stay within yellow lines. Nowadays vehicle uses Adaptive Cruise Control (ACC) which has LIDAR technology. It helps the vehicle that is in cruise control to slow down when there is a vehicle in the front and also speed up when there is no traffic.
2]Obstacle Detection in Autonomous Vehicles:“This is probably one of the biggest uses of LiDAR technology in the recent past. Autonomous vehicles use LiDAR technology to sense obstacles in their paths and to avoid collisions with other obstacles or vehicles on the road.”
3]Transforming the Real World view with Augmented Reality (AR) : Augmented Reality (AR) might not be the same as virtual reality, but the technology is proving itself as a very useful tool in our everyday lives. The AR is rapidly growing in popularity because it incorporates the elements of the virtual world into the real world that enhances the things we see, hear, and feel. AR merged with LiDAR can heighten the transparency and final output of AR systems. In principle, a LiDAR scanner offers the ultra-detailed 3D mapping which allows another AR system to pile his data on top of a precise and reliable map. The point cloud created by LiDAR scanner can offer an extraordinary AR experience. Currently, there is research going on the application of Doppler wind LiDAR, which would allow us to see the clear movement of the wind. The research would be useful in aviation safety, data visualize of atmospheric, weather forecasting and disaster management.
4]Landscape Analysis : The most common use of LiDAR technology is to survey the landscapes. With the recent advancement in hardware and software sector, the analysis of LiDAR data can be processed more efficiently. The remote sensing technology can enter in thick shades, which allows the scientists to uncovered earth territory models that was not visible to them by picture based photogrammetry. A comprehensive and updateable risk model can be introduced allowing risk to be managed, rather than responded to.
5]Biodiversity for Species and Insects : Forest is home of different species and insects. To unveil the mystery of their lifestyle LiDAR technology is used. Using LiDAR, scientist and researchers gather data about various species and insects. Then, the gathered data is analyzed to see whether the forest is a suitable place for them to live or not. Essentially, the vertical arrangement of trees, shrubs, and other plant tell what species can live and prosper in that area.
6] Tsunami Hazard Model : We all had known about tsunami and its effect on human lives. The natural disaster can destroy infrastructure and take a thousand lives. However, LiDAR technology can help to minimize this damage. Scientists can utilize LiDAR technology to understand the area that will be covered when the tsunami happens. The 3D CG representation of a terrain’s surface produced by LiDAR gives the elevation value of the seashores and bathymetric data provides underwater elevation. The data layered in the GIS gives us the flood area details when a tsunami occurs.
7]Aiding Forensic Researchers : Due to LiDAR’s capabilities to survey areas and detect life form, the researchers pondered on whether LiDAR technology could be used to find unmarked graves. For this, the researches obtained numerous corpses that had been donated to science and buried them in various unmarked graves. Using LiDAR technology, the researchers were able to make out the outlines of all of the graves even those that were covered by leaves and other debris.
8]Agriculture : Farming is becoming more technologically advanced than before. Maintaining a profitable agricultural business is becoming impossible without technology, and LiDAR’s role is becoming increasingly important. Farmers use LiDAR to map their fields, while LiDAR-equipped drones create digital elevation and vegetation models. Moreover, LiDAR technology allows farms to reduce flooding and provide better drainage by mapping fields.
In future the LIDAR technology can also be used in Behavioral analysis , Robotics , Health care etc…On top of that, as LiDAR sensing becomes more advanced, it can be used for interpreting body language and reading facial expressions.LiDAR gives people the opportunity to transform their lives in a big way. Its gradual price reduction and advancements in security, reliability, accuracy and design will motivate businesses from various industries to adopt LiDAR to stay competitive on the market. After all, who wouldn’t want a parcel delivered to them by a robot?