Hello everyone,
In this post, I want to talk about the LiDAR technology and how does it work;
LiDAR, or light detection and ranging, is a popular remote sensing method used for measuring the exact distance of an object on the earth’s surface. It uses a pulsed laser to calculate an object’s variable distances from the earth's surface. These light pulses — put together with the information collected by the airborne system — generate accurate 3D information about the earth's surface and the target object. LiDAR systems are divided into two types based on their functionality — Airborne LiDAR & Terrestrial LiDAR.
Airborne LiDAR
Airborne LiDAR is installed on a helicopter or drone for collecting data. As soon as it’s activated, Airborne LiDAR emits light towards the ground surface, which returns to the sensor immediately after hitting the object, giving an exact measurement of its distance. Airborne LiDAR is further divided into two types — Topological LiDAR and Bathymetric LiDAR.
Terrestrial LiDAR
Unlike Airborne, Terrestrial LiDAR systems are installed on moving vehicles or tripods on the earth's surface for collecting accurate data points. These are quite common for observing highways, analyzing infrastructure, or even collecting point clouds from the inside and outside of buildings. Terrestrial LiDAR systems have two types — Mobile LiDAR and Static LiDAR.
LiDAR follows a simple principle — throw laser light at an object on the earth's surface and calculate the time it takes to return to the LiDAR source. Given the speed at which the light travels (approximately 186,000 miles per second), the process of measuring the exact distance through LiDAR appears to be incredibly fast. However, it’s very technical. The formula that analysts use to arrive at the precise distance.
There are broadly two types of LiDARs used in autonomous vehicles. These are classified based on how they scan their surroundings. The 3D flash LiDAR consists of a wide-angle source and wide-angle optics to focus all the reflected light from one exposure onto the detector. This information is then used to model the surroundings based on time-of-flight calculations. The scanning LiDAR is a system that emits light sequentially in every direction and detects the echoes one by one to map its surroundings.
