background
(Xinhua) As of 22:00 local time on the 29th, the 11th Japan earthquake and the tsunami triggered by it have caused 11,168 deaths and 16,407 missing persons. The picture of the earthquake-stricken area is shocking. How can the rescue team find as many survivors in the rubble as possible during the limited time? "Life-saving box" ---- life detector has attracted widespread attention from netizens. This article elaborates on the working principle, classification, standards, and latest products of life detectors.

working principle
In layman's terms, as one of the important technological weapons often used in post-disaster rescue work, the life detector is actually a breathing and motion detector. 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. The life detector works by testing the breath movement or movement of the detected person. It can capture very weak movements very keenly, and the powerful algorithm processing is the best helper of the safety rescue department.

Life detector classification
According to the type of sensor, mainstream life detectors have the following types:
1. Audio life detector (including sound wave, shock wave)
2. Video life detector (including optical, fiber optic, infrared)
3. Radar life detector (including imaging, non-imaging)
4. Gas-sensing life detector (such as carbon dioxide detector)

Disadvantages and related applications
The life detector cannot be sure of several people. There are only signs of life that can be detected. During the search and rescue of the Sichuan Wenchuan earthquake on May 12, 2008, experts from China and other countries around the world used life detectors to detect and rescue tens of thousands of trapped victims in search of help. Among them, the longest competitor buried in the search was more than 216 hours! Similarly, in the search and rescue of the Wenchuan earthquake in Sichuan, it played an indelible role!

The most advanced life detector
Among various life detectors, DKL Lifeguard is the most advanced in the world. It detects life traces by detecting ultra-low-frequency waves emitted from the human heart, and can penetrate rubble, reinforced concrete, and bricks in the rubble. Even water finds survivors. The life detection technology quickly matured after 9/11. Initially, it was developed by the DKL company that specializes in life signal search in the United States at the end of the last century. It was only a single model of hand-held detection equipment used in the US Navy. . This product, which extends from the military to the rescue field, can detect information on the activities of people 2 kilometers away in the open desert.

The most compact life detector
An island nation like Japan has done enough homework on earthquake prediction and rescue equipment because it is located in earthquake-prone areas. A geological survey and research institute in Japan recently developed a compact life detector SAR2700, which can quickly detect the exact location of the life that is buried in the rubble in the ruins of fires and earthquakes. Its greatest feature is that it can quickly be based on The heartbeat's heartbeat electromagnetic wave intensity and direction illuminate the precise location and depth of the ground. The instrument is very small, like a cigarette box, and weighs 950 grams. Based on the principle of electromagnetic radiation, firefighters take it in their hands and can easily detect whether there is a range of 6 to 12 meters. The existence of life can also be detected as the existence of plural lives, that is, one or several people are trapped in the depravity and failure. The instrument has a display screen, just like a cell phone, with one or several red symbols on the screen, which proves that there is life underground and can show the horizontal distance between the trapped and the rescuer in the rubble. , the depth of the ground and the state of orientation, etc. The search limit is 12 meters. In the rescue process, the use of this instrument can confirm the place of life within three minutes.

The government purchases earthquake emergency rescue equipment
Recently, on the basis of setting up 10 earthquake emergency rescue teams, the Seismological Bureau of Bozhou City, Anhui Province, purchased a number of specialized equipment that meets the characteristics of earthquake emergency rescue and is equipped with rescue teams. Including life detectors. The purchase of professional equipment not only effectively enhanced the earthquake emergency rescue capability of Ganzhou City, but also provided a solid material guarantee for the safety of people's lives and property, and provided the possibility of supporting earthquake emergency rescue in the surrounding areas.

Seismic life detector standard missing
At present, on the market, quotes about life detectors are varied, with tens of thousands, hundreds of thousands, and even millions, making people dazzled. So far, life detectors do not have national standards or industry standards, and there are no uniform regulations on names, model specifications, and there are no authoritative certification tests for product comprehensive performance. Policy loopholes may not only lead to chaos in the life detector market, but also fail to control product quality. In actual rescue, it is difficult to achieve the expected rescue target and affect the progress and results of the rescue.