LiDAR stands for “Light detection and ranging”. LiDAR is a system that combines three technologies: laser, GPS and INS to obtain point cloud data and generate accurate digital 3D models.
The combination of these three technologies allows for the acquisition of a 3D realistic view of the surrounding area with consistent absolute measurement of point locations.
This technology is similar to what we know as radar, where the radar transmitting system sends a signal that is reflected by the target and collected by the receiving system, and the distance to the target is determined by measuring the runtime of the reflected light.
LiDAR uses pulsed lasers to measure distance in a similar way to radar.
LiDAR emits a laser beam and calculates the distance from the LiDAR to the target by measuring the time it takes for the light to hit an object or surface and reflect back, creating a data point, a process that can result in millions of data points, which scientists refer to as a “point cloud.
By processing this data, an accurate three-dimensional visual image can be rendered in seconds.
Since the speed of light is known, the distance between the laser and the measured object can be calculated based on the time difference between the emitted laser beam and the received time of the backward scattered light.
LiDAR technology has been developed over many years and has been used in numerous fields!
In 1968, Hickman and Hogg of Syracuse University built the world’s first laser-based seawater depth measurement system.
The system was designed to achieve ocean depth measurements by the time difference between different echoes of computer-borne LiDAR and demonstrated the feasibility of laser bathymetry technology for the first time.
In the late 1970s, the National Aeronautics and Space Administration (NASA) successfully developed an airborne ocean lidar with scanning and high-speed data recording capabilities.
It was used in the Atlantic Ocean and Chesapeake Bay for bathymetry and mapped the seafloor topography in water depths less than 10 m.
Since then, the huge application potential of airborne lidar systems began to receive attention and was soon applied to terrestrial topographic survey studies.
In the late 1990s, the development of GPS and inertial navigation systems made it possible to accurately and instantaneously position and fix the attitude during laser scanning.
In 1990, Professor Ackermann of the University of Stuttgart, Germany, led the development of the world’s first laser profiling system, which successfully combined laser scanning technology with an instant positioning and attitude system to form an airborne laser scanner.
In 1993, the first commercially available airborne LIDAR system, the TopScan ALTM 1020, appeared in Germany, and in 1995, airborne LIDAR equipment was commercially produced.
Since then, airborne LiDAR technology has become an important complementary tool for forest resource surveys.
It is widely used to quickly obtain large-scale forest structure information, such as tree positioning, tree height calculation, canopy volume estimation, etc. It also provides information for forest ecology research, forest management, and management to estimate parameters such as vertical structure stratification, carbon stock, and the amount of dead leaves and flammable material.
With the progress and development of LIDAR technology, the development and application of satellite-based LIDAR gradually matured in the 1990s.
In 2003, NASA formally included the geological laser altimetry in the Earth Observation System of Systems (EOS) based on an earlier plan to use satellite-based LIDAR to measure ice changes in the polar regions, and launched it on board the ice, cloud and land altitude monitoring satellites for liftoff operations.
LIDAR technology has been developed and used in various fields; the main applications include stereo mapping, mining, forestry, archaeology, geology, seismology, topography, and cloister mapping, among others.
LIDAR technology is also used in driverless cars, which have been researched by major technology companies in recent years.
LiDAR has become one of the most discussed technologies to support the shift to autonomous driving.
In the Baidu driverless car, which was successfully road tested on December 10 last year, a large LiDAR was placed on the roof of the car, in addition to sensors such as millimeter-wave radar and video.
LIDAR can make driverless cars have 360 ° all-around dead-end visibility to ensure the safety of driving.
Comprehensive information, we can learn that LiDAR is more often used in the military, industry, and other fields, less in the civilian consumer sector, not to mention the same as Apple for cell phones.
The main reasons why this technology is not popular are:
(1) work under the influence of weather and atmosphere
The laser generally attenuates less in clear weather and travels farther. In heavy rain, smoke, fog, and other bad weather, the attenuation increases sharply, and the propagation distance is greatly affected.
(2) Difficulty in searching the target
The LIDAR beam is extremely narrow, so it is very difficult to search for targets in space, which directly affects the interception probability and detection efficiency of non-cooperative targets, and can only search and capture targets in a small range, so LIDAR is rarely applied directly to the battlefield for target detection and search.
(3) High cost and large size
Take the driverless car being tested as an example, Baidu driverless car equipped with LiDAR costs up to more than 700,000 RMB, Google is also using the same high-end configuration LiDAR in the testing of driverless cars.
In 2020, Apple applied LiDAR to cell phones for the first time, so what new functions can the iPhone loaded with LiDAR achieve?
First of all, the iPhone can use LiDAR in portrait focusing, and can also imitate the depth of field effect of professional cameras.
At the same time, LiDAR can also optimize the focusing part of the shot, providing higher accuracy for focusing, even in complete darkness.
In addition, the higher accuracy 3D modeling capability that LIDAR can bring plays a key role in enhancing AR applications.
The implementation of all these functions requires the performance of powerful computing processors.
Perhaps in the future, our smartphones will be equipped with this technology, which not only makes cell phone photos and videos better but also adds more ways to play in the AR field.
In recent years, LiDAR has been used in more and more scenarios, attracting many researchers to invest in it.
Velodyne LiDAR received a $150 million co-investment from Baidu and Ford in 2016.
Velodyne shipped more than 3,000 units in 2015, with cumulative sales exceeding 30,000 units by 2019 and sales reaching $500 million. The global LiDAR market size is expected to reach $6 billion in 2024.
At present, there is still a lot of room for progress in LiDAR technology, and the problems encountered by LiDAR technology now will surely find a good solution, and this technology will slowly integrate into our lives just like smartphones and other devices!
