用于提高非接触体温测量精度的恒低温环境系统的设计与实现

Design and Development of a System with Low and Constant Temperature to Improve the Precision of Non-contact Body Temperature Measurement

目前非接触体温测量已成为研究体温测量方向的热点问题。普遍采用的非接触体温测量的方法是红外辐射法,即用热电堆传感器把人体辐射的红外线能量转化成电信号,但热电堆传感器易受到环境温度影响。提出一种适合于红外传感器的恒低温环境系统的设计方案,可以避免环境温度变化对红外传感器输出信号的影响,且可以增加输出信号的信噪比。采用半导体制冷片(TEC)作为控温的执行器件,利用单片机输出的脉冲宽度调制(PWM)信号对半导体制冷片进行控制,采用PID算法控制调节PWM的占空比。当控温基线在0℃时,温度波动小于0.05℃。

Nowadays, infrared radiation is adopted widely for non-contact body temperature measurement, using detector to change the infrared energy radiated by the body into electrical signal, but the detector itself is easily influenced by environment. A system with a low and constant temperature was designed and developed in our lab. Thermoelectric coolers（TEC） was used to control the temperature, and proportional integrating differentiation （PID） algorithm to adjust the duty factor. The temperature fluctuation was less than 0.05 ℃ when the temperature was controlled at 0 ℃. The system could avoid the influence on the output-signal of infrared ray detector by the unstable temperature of the environment and increase the signal-to-noise rate.