| As a main way of non-contact measurement, infrared measurement has many advantages, such as rapid reaction, wide measurement range and high sensitivity etc. Therefore, non-contact thermometry can be used in variety of spots. When infrared thermometer is used in medicine, The range of infrared thermometer is regulated between 24.0 ℃to 45.0 ℃ and its precision must be 0.1 ℃ when it is used in medicine. But most of infrared thermometer couldn't achieve this regulation. Meanwhile, in this temperature range, the precision of infrared thermometer can be greatly affected by ambient temperature. The error will increased greatly too. After looked up lots of data and realized the defect of infrared thermometer in medicinal scopes, a new compensatory way on environmental temperature is presented in this paper. This new way bases on the principle of pyroelectric detector and defines the quantity of compensation according to the temperature difference between target and its surrounding. The ambient temperature is measured by a digital chip and processed with software. This new way can overcome the defect of thermal resistance. After focused by lens, chopped by chopper and received by detector, infrared signal is transformed to electric signal whose frequency is 20 Hz in this infrared system. The electric signal is processed, compensated and displayed in micro-controller system after it is amplified, filtered and adjusted by circuit. During design of this infrared system, micro-control is debugged with Wave6000 simulation system and software is compiled in assembly language because of timing relation between every part. The test of this infrared thermometer indicates that precision and stability has improved already. But it couldn't reach our country's standards on medicinal thermometer.
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