"Four Weapons" to Detect Life

In the Sichuan earthquake disaster relief and rescue, a rescue professional equipment named “Life Detector” played an important role for rescue workers to find survivors in the rubble. So, what kind of equipment is the life detector? What are the functions? A few days ago, the reporter asked the relevant professionals to answer.

According to reports, at present, there are mainly four types of life detection technology devices on the market: infrared thermal imaging detectors; sound and vibration life detectors; snake eye life detectors; and radar life detectors.

Infrared thermal imaging detector

The infrared thermal imaging detector has all-weather working characteristics, and judges different targets by sensing the temperature difference between the target and the background, and images according to the temperature distribution characteristics.

In the surface search, it is difficult for the human eye to distinguish the target in the rubble or the difference in limbs, debris and debris that protrude from the gap. The infrared thermal imaging detector can judge the difference between the target of the living body and the temperature of the surrounding environment. The existence of goals.

It is characterized by the ability to quickly search large areas of trapped persons on the surface of the rubble and to work 24 hours a day; however, it cannot image the buried objects.

Sound wave vibration life detector

The sonic vibration life detector relies on the identification of sounds from trapped persons. Humans have two ears. This instrument has three to six vibration sensors, also called vibration sensors. It can determine the specific location of survivors based on the small differences in the sounds heard by each ear. The instrument can extract the human vocal frequency to distinguish the surrounding noise. If the survivor can no longer speak, just tap with your finger and make a slight noise that can also be heard by it.

The advantage of the sonic vibration life detector is that it can discriminate the existence of a certain depth of life on the surface and underground; however, it is easily affected by the surrounding broadband noise.

Snake Eye Life Detector

Snake Eye Life Detector is an optical fiber image transmission video system, also known as "optical life detector." The optical fiber bundle has a freely bendable performance, and a high-definition color image can be seen on the monitor in real time, so it is particularly suitable for quick qualitative inspection of difficult-to-reach places and is widely used in mines, earthquakes, and landslides. Particularly suitable for: search and rescue of miners buried under rubble during mining accidents; searching under earthquake buried pressure; vehicle stowaway inspection; narrow space rescue.

The disadvantage is that it cannot be detected for the occluded target.

Radar life detector

The radar life detector is actually a respiratory and motion detector and works by testing the breath movement or movement of the detected person. Because of the low frequency of breathing, which is usually 1 or 2 times per second, breathing exercises can be distinguished from other higher frequency sports. The principle of measuring movement is also roughly the same. The radar signal transmitter continuously emits electromagnetic signals and scans a certain space. The receiver continuously receives the reflected signals and performs algorithm processing on the returned signals. If the detected person remains stationary, the return signal is the same. If the target is moving, the signal will be different. By comparing the signals received in different time periods and other algorithm processing, it can be determined whether the target is moving.

Its basic features include: instant movement detection, detection of movements through concrete, brick, snow, ice and mud, detection of the distances of persons in distress; work under all climate conditions; intuitive and easy to learn, without the need for extensive specialization Training; low requirements for power supply; almost no system maintenance; no need to mute the environment, making search and rescue work easy.

There is also a life detector that detects ultra-low-frequency waves emitted from the human heart, and any animal except the human body is not detected. When the electric field generated by the low frequency wave emitted by the human heart is detected, the detection bar will automatically lock this electric field. When the human body moves, the detection bar will also follow the movement. The operator can search for the location of possible survivors without having to shut down other implements or interfere with lifeguard dogs or other rescue work.