Memahami bagaimana rangefinders kerja
Optik jarak meter
Optik rangefinders are divided into two types, phase method rangefinders and pulse rangefinders, according to the method of measuring distance.
Pulse rangefinder is the use of the target object to launch a beam of light, determine the target will be reflected back to the time of the light, so as to calculate the distance between the instrument and the target, due the laser has a good directionality, a single wavelength, so it is photoelectric rangefinder is generally use the laser as modulation object, so the pulse type rangefinder is also commonly known as the laser rangefinder.
Menggunakan the pulse method of ranging laser rangefinder can reach a wide range of range, can be used for indoor and outdoor measurements, its typical range of 3.5 metres to 2000 metres, high range laser rangefinder can reach 5000 metres, military use of laser rangefinder can reach even farther range. As a result of the ability to measure a long-distance measurement target, in order to range the target intuitively observed by the user, so the laser rangefinder generally has a telescope system, also known as the laser rangefinder telescope, Figure 1 for the three-cylinder laser rangefinder telescope of a typical diagram.
Laser rangefinder accuracy depends mainly on the instrument to calculate the laser issued to receive the time between the calculation of accuracy, according to the technology and application occasions laser rangefinder can be divided into the accuracy of about 1 metre of conventional laser rangefinder (terutamanya used for outdoor sports, hunting, etc. ) and used for surveying and mapping, land survey, construction, engineering applications, military and other occasions requiring higher accuracy of high accuracy type of laser rangefinder.
Phase method rangefinders are rangefinders that modulate the phase of the laser and obtain the distance by measuring the phase difference of the reflected laser. Kerana daripada the need to reflect back to the laser phase phase detection, so the requirements of the received signal needs to have a strong intensity, taking into account the safety of the human eye, so can not be used as a pulsed laser rangefinder telescope system, and the range is small, ranging from the typical range of 0. 5mm to 150 Metres, the General phase method of laser rangefinders using the 635nm (vision for the Red) laser as the object of the debugging, also known as the infrared rangefinder. commonly known as infrared rangefinder, but in fact the definition of the laser is not defined by the colour, and the use of 635 nm laser rangefinder if direct exposure to the human eye will cause irreversible damage, please pembaca betul use and protection.
Sonic Jarak Mengukur Instrumen
Akustik distance measurement is the use of sound waves reflective properties and measurement of an instrument, generally using ultrasonic waves as the modulation object, that is, ultrasonic rangefinder. Ultrasonic transmitter to a certain direction to launch ultrasonic waves, in the launch at the same time to start timing, ultrasonic waves in the air propagation, on the way to meet the obstacles will immediately return to the ultrasonic receiver to receive the reflected wave immediately interrupt to stop time. By constantly detecting the reflected wave that meets the obstacle after the wave is emitted, the time difference T between the emitted ultrasonic wave and the received wave is measured, and then the distance L is dikira.
Due to the ultrasonic propagation speed in the air by the temperature, humidity, air pressure, etc., so the measurement error is larger, and due to the longer ultrasonic wavelength, resulting in a shorter propagation distance, so the general ultrasonic rangefinder measurement distance is relatively short, the measurement accuracy is relatively low. But the use of ultrasound into a fan propagation characteristics, its detection range is larger than the photoelectric rangefinder, in the actual project is widely used in security, cable height measurement, obstacle detection and other fields.
