What are the detailed classifications of rangefinders?

At present, the market is full of various rangefinders, including industrial rangefinders, underwater rangefinders, foggy rangefinders, indoor rangefinders, remote rangefinders, high-frequency rangefinders, etc. According to the working principle, we can divide the range finder into the following three categories: Laser Range Finder: Laser Range Finder is a widely used sensor at present. Its design is flexible, the volume is small, easy to operate, and it is very popular in both industry and home. This is an instrument that uses laser to accurately measure the distance of a target. When working, a very fine laser beam is emitted to the target, the photoelectric element receives the laser beam reflected by the target, the timer measures the time from the emission to the reception of the laser beam, and calculates the distance from the observer to the target. Ultrasonic range finder: Ultrasonic range finder, because the ultrasonic is greatly affected by the surrounding environment, the general measurement distance is short, and the measurement accuracy is low. At present, the scope of application is not very wide, but the price is relatively low, usually a few hundred yuan. According to the characteristics of the ultrasonic wave reflected back by the obstacle. The ultrasonic transmitter emits ultrasonic waves in a specific direction and starts timing at the same time of emission. Ultrasonic wave spreads in the air and will return immediately when encountering obstacles on the way. The ultrasonic receiver will immediately stop timing when receiving the reflected wave. By continuously detecting the echo reflected by the obstacle after the transmitted wave, the time difference T between the transmitted ultrasonic wave and the received Echo is measured, and then the distance L is calculated. Infrared rangefinder: the advantages of infrared rangefinder are cheap, easy to manufacture and safe. Its disadvantages are low precision, short distance and poor directivity. An instrument that uses modulated infrared light for accurate ranging. The measurement range is usually 1-5 kilometers. The principle of non-diffusion when using infrared ray propagation: Since the refractive index is very small when infrared ray passes through other substances, the long-distance rangefinder will consider infrared ray, and the propagation of infrared ray takes time. When the infrared ray is emitted from the rangefinder and meets the reflector, it is reflected back and received by the rangefinder, and then the distance is calculated according to the time from transmission to reception and the propagation speed of the infrared ray. Although the rangefinder is used to measure the distance, the appropriate rangefinder should be selected for different measuring environments and objects to be measured to accurately meet our requirements.