Three Life Detectors and Their Applications in Earthquake Rescue

Abstract: Life search is the most important issue in the emergency rescue of earthquakes. It is the most difficult problem that the time is tight and the environmental conditions are harsh. Advanced technology and equipment are technical guarantees to increase the success rate of rescues and minimize the number of casualties. Utilizing domestic and foreign related technologies that are relatively mature at present, the optical probing apparatus, acoustic wave/vibration probe device, and infrared thermal imager developed and developed are advanced, lightweight, efficient, and practical seismic rescue on-site life search and positioning technology devices and utilization systems. The principles of engineering and modern management theory carry out the research on the life search and rescue support system for earthquake disasters, and thus establish an earthquake rescue life search and positioning technology system.

Key words: Earthquake rescue; Life search; Prognosticators The fact that the earthquakes at home and abroad have been used to save lives proves that the faster and more timely the rescue personnel are being rescued, the more likely it is to rescue them. According to statistics from relevant experts, after the Tangshan earthquake, the rescue rate was saved by the embossed personnel in the first day after the earthquake was 81%; the survival rate was saved by 53% in the second day; and the survival rate was 36.7% in the third day. Within the fourth day, the rate of salvation was saved by 19%; the rate of salvation was saved by 7.4% in the fifth day; hopes for survival would be small in the evening. The above data shows that the earlier the implementation of the rescue, the more people are rescued; in particular, it is a crucial period for rescue of trapped people within 72 hours after the earthquake.

With the acceleration of China’s modernization and urbanization, the scale, height and span of urban buildings and structures are gradually increasing, and the population density is also increasing. In the event of an earthquake disaster, the level of casualties, destruction of buildings (buildings) will be more serious, and the difficulty of rescue work will increase. This poses higher requirements for rescue technology and equipment. In order to implement efficient and orderly rescue of trapped people, in addition to ensuring that the emergency rescue team responds quickly, is highly mobile, and has strong surprises, it is equally important to have the necessary high-tech rescue equipment. Advanced rescue technology and equipment are technical guarantees to increase the success rate of rescues and minimize the number of casualties. However, our country is almost blank in the field of earthquake emergency assistance and high technology, and lacks practical and effective rescue equipment. We urgently need to carry out research on high-tech rescue technologies and study key technologies in earthquake rescue technologies.

Fig.1 System diagram of Earthquake Aid Life Search and Positioning Technology 2 Main research contents, technical ideas and key technologies Development of non-contact life search and positioning technology to detect physiological, physical, and chemical information from survivors of collapsed structures (structures) , and determine the position, number, and living conditions of the pressured and buried personnel, and give appropriate physiological and psychological support to the trapped persons so as to increase the success rate of rescue. Study the earthquake search and rescue support system on the scene of earthquake disasters, propose urban search and rescue theory in line with Chinese characteristics, formulate and complete practical techniques and regulations for on-the-spot search and rescue of urban earthquake disasters, and thus establish an earthquake rescue life search and positioning technology system (Figure 1). .

2.1 Optical probing apparatus The optical probing apparatus consists of probes, variable length metal rods, and monitors. It can be drilled through the voids in the piled-up layers of the rubble or through a dedicated drilling rig, reaching into the vicinity of the trapped person to determine its position and living condition.

Optical probing equipment is mainly used to find trapped people quickly and accurately in the broken walls caused by disasters such as earthquakes. Therefore, in the development of the optical probing device, the severe conditions of the earthquake disaster relief site and the special requirements for the instrument were fully taken into account: 1 The instrument enters the channel and the use of space is small, the obstacle factors change; 2 The effective sound and light from survivors The information is often very weak; 3 the site after the disaster is often no electricity, dark climate conditions are poor; 4 instruments should have direct display, micro-sound detection and call functions.

The technical idea of ​​developing an optical probing apparatus is to use a light source module, a spherical image plane objective lens, an optical correcting mirror, and an image sensor to constitute a micro light probe, and the microphone and the speaker are miniaturized and integrated on the probe and passed through the wires in the variable length rod body. Send audio and video signals to the monitor (Figure 2). The optical probing apparatus uses a spherical image imaging objective lens and two-way transmission audio and one-way transmission video technology. The key technical contents and technical processes include: (1) the development of small sphere image plane imaging objectives, scientific calculations and experiments to determine the best angle of view; 2 through simulation experiments to sum up the spatial arrangement and combination of the various components of the probe.

Figure 2 Optical Probing System Block Diagram 2.2 Acoustic/Vibration Probes The Acoustic/Vibration Probe is a high-sensitivity sensor, high-precision dedicated data acquisition system and multi-purpose special data acquisition system and multi-purpose special computer processing system. The detection system can detect and analyze the movement of the survivors, taps and calls through the medium to send a tiny vibration signal to help determine the location of the trapped person. The system is a detection system based on human-computer interaction, including signal detection, monitoring, selection, storage and processing. The processing and recognition system is implemented in a modular design, making it quick and easy to upgrade.

The technical idea of ​​developing the sound wave/vibration probe is to establish a signal processing detection system composed of a highly sensitive sensor, a high-precision data acquisition card, and a dedicated computer. Detect the weak distress signal sent by trapped people and determine the location of trapped people (Figure 3).

Figure 3 Sound/Vibration Probe System Block Diagram Development The sound wave/vibration probe was based on an in-depth study of the acoustic/vibration mathematical model and was judged using computer technology. The key technical contents and technical processes include: 1 the development of high-sensitivity sensors; 2 the research on the mathematical model of acoustic waves and vibration waves to determine the validity criterion of signals and the determination of the position of effective signal sources.

2.3 Infrared Thermistors Any object that emits infrared radiation above absolute zero will be the same as the human body. Studies have shown that the infrared radiation characteristics of the human body are different from the infrared radiation characteristics of the surrounding environment. The thermal imaging life detector uses the differences between them to separate the target to be searched from the background by imaging. According to Planck's radiation law, the central wavelength of infrared radiation at 37°C is λ=9.4μm, and 8 to 14μm account for 46% of the total radiation energy of the human body. This spectral segment is designed for thermal imaging. An important technical basis for life detectors. The thermal imaging camera is not limited to the illumination of the working environment and does not require additional light sources. It can search for life in the atmosphere of heavy smoke, fire and darkness after an earthquake. The main content of infrared thermal imager development is to research and develop advanced, lightweight, efficient, safe and practical helmet-type infrared thermal imager. The purpose of developing into a helmet type is to liberate the user's hands for rescue, which is more suitable for use in the post-earthquake rescue environment.

Figure 4 Infrared Imager System Block Diagram The technical ideas and features of the infrared thermal imager developed in this project are that the probe uses the uncooled focal plane (UFPA), and it is miniaturized and integrated on the helmet (Figure 4). The key technical contents and technical processes include: 1 the selection of focal planes and the development of probes; 2 miniaturization of high-precision infrared thermal imaging systems and their integration in helmets.

2.4 Earthquake Disaster Site Life Search and Rescue Support System Passes through the existing earthquake emergency response organization system in China, the theory, methods and practice of life search and rescue at home and abroad on earthquake disaster scenes, the application of high and new technology on the scene of earthquake rescue, and the safety and security technology Basic research to discuss the role, characteristics, and internal links of the major factors supporting the completion of city search and rescue missions, and to establish an on-site search and rescue model of urban earthquake disasters that meet China's national conditions, and to form a relatively complete life search and rescue support system for earthquake disaster sites. . Guide earthquake disaster relief on-site search and rescue work, give full play to the role of high-tech rescue equipment, and implement effective relief for survivors buried under pressure. The key technical contents and technical processes of this topic include: 1) The application of search theory in urban earthquake disaster relief sites; 2) Research on the type of buildings collapsed and the model of living space.

3 Work Progress Since 2001, the research work has progressed smoothly. The research of the support system has basically been completed. The key components and most of the components of the three scientific prototypes of the Optical Probing Apparatus, Sound Wave/Vibration Detector, and Thermal Imager have been completed. The development work has been completed and system integration work is ongoing.