What Is a LiDAR Sensor?
A LiDAR sensor is a device that measures the distance and shape of an object by emitting a laser beam and detecting the reflected or scattered light.
LiDAR, an acronym for light detection and ranging, is often used in time-of-flight light detection and is also known as a time-of-flight (TOF) sensor. The frequency-modulated continuous wave (FMCW) method, which utilizes the Doppler effect for advanced measurements, is another application of this remote sensing technology.
Uses of LiDAR Sensors
LiDAR sensors are crucial in automotive autonomous driving technology and smartphone image detection. They detect obstacles and vehicles nearby, aiding in the development of ADAS (Advanced Driver-Assistance Systems) to improve safety and reduce costs.
Additionally, LiDAR sensors are employed in factories alongside image processing equipment and smartphone cameras for applications such as photography focus blur, virtual reality (VR), and augmented reality (AR). The inclusion of LiDAR sensors in Apple’s iPhone 12 Pro and iPhone 12 Pro Max has significantly raised their profiles.
Principle of LiDAR Sensors
The principle of a LiDAR sensor involves using a physical method to measure the distance to an object by receiving laser light, utilizing a laser as the light source and a light-receiving element. The TOF method, the most widely used, calculates distance by measuring the time it takes for laser light to return after reflecting or scattering.
There are two laser beam irradiation methods: wide-field irradiation and scanning, which involve directing laser beams in specific directions and scanning them.
1. Wide-Field Irradiation Method
The wide-field irradiation method, akin to a TOF camera, captures the entire field of view at once with a single light beam. This method is cost-effective due to its simple optical system but can be influenced by ambient light due to reduced photon density per pixel.
2. Scanning Method
The scanning method employs a mirror to direct the laser beam, with variations such as point-scan for individual pixels and line-scan for rows. The line-scan method is preferred when high spatial resolution is not essential due to its quicker measurement time.
Other Information on LiDAR Sensors
1. Differences Between TOF and FMCW Methods
The TOF and FMCW methods differ in the physical quantities used for distance measurement. The FMCW method, which measures distance using the Doppler effect of the reflected wave, promises more advanced measurements than the simpler TOF method. Despite the challenges in coherence and cost reduction for FMCW, it is the focus of active research, especially for automated driving technology.
2. LiDAR Sensor Camera
Integrating LiDAR sensors with cameras into a single unit eliminates parallax, allowing for highly accurate, distortion-free measurements and high-resolution 3D image creation. This integration is particularly beneficial for in-vehicle sensors.
3. Demand Forecast for LiDAR Sensors
With the advancement of autonomous driving technology, led by companies like Toyota, the demand for LiDAR sensors is expected to grow significantly. Market research by the Yano Research Institute Ltd. predicts the LiDAR and laser market will reach 495.9 billion yen by 2030, with Yor Development forecasting a market size of $6 billion by 2024, indicating a rising demand in developed countries.