Theoretical And Experimental Research On Detecting Thermal Trace Of Human Being

Any object has infrared radiation. The heat from hotter object transmits to the adjacent objects or the surroundings by conduction and convection. The thermal trace which represents its whereabouts remains during this process. The diffusions of thermal traces are time-dependent. Some takes relative long time. Previous studies were limited by the lacking of detecting equipment. Few application of this technology was conducted. Recently, infrared camera with high resolution and high acquisition rate is gradually introduced to this area, providing a good method to detect the thermal traces.In many applications, such as thermal rescuing after disaster, scout and military affairs, if we detect the thermal traces in time and judge it's forming time and removal time, we can analysis and obtain the human body's track. It provides importance evidence for recognizing, localization, searching and continuous tracking. However, the difficulty of qualitative and quantitative analysis increases in the process of forming human thermal traces, partly due to irregular contacted area, non-uniform or uncertain contacted temperature, complex boundary conditions, etc., As results, the process is diffucult to describe using a set of differential equations with a condition specified for the exact solutions. The reverse problem of forming time is more difficult. Systematic and comprehensive models are needed in the theoretical analysis in order to detect the thermal trace.To improve the detecting and recognizing ability of infrared system, the essence and significance of the characterization on the temperature field of human body in indoor environment is systematically discussed according to bio-heat equation on the basis of the physical structure, fifteen segments model and thermoregulation system. The various factors that influence body temperature are analyzed. The theories and methods of calculate the radiant flux intensity of human body are proposed, the detecting model is estabilished in this thesis. The results provide theoretical basis for improving efficiency and accuracy of recognizing human body using infrared system. The experimental results indicated that the error of theoretic results falls in the allowable range.To improve the ability to discriminate the thermal trace obtained by infrared system, we must study the heating and cooling process by observing the body contact and removal on an object respectively, accurately get the influence of parameters on detection. In this thesis, the theoretical model of infrared trace of human body is established.The relationships between the temperature and material thermal parameters, contact temperature, contact time are studied based on comparative analysis by finite element simulation and by experiment. The thermal distribution and the changes of the thermograph's contrast are found, which demonstrate that the temperature is sensitive to the material thermal parameters. The computations fit the experimental results very well. Conclusively, the data of experiment, the models of computation and the conclusion we obtained can be valuable for application of this technology. Using this model, the curves which describe the relationship between the body's removal times with the evolutions of temperature fields are obtained. They are useful for tracking the human being.Characteristic of human body's infrared images are that their difference in temperature are low and the signal-to-noise of are low; finally, the algorithmic of energy accumulation of images based on image registration is put forward in this thesis. The images acquired by different azimuthally target detection are registrated. Their energy is accumulated. The contrast and signal-to-noise are improved by these methods. The ability to distinguish the target is enhanced...