How to do research on temperature compensation technology and medical infrared thermometers
Infrared temperature measurement is one of the most important non-contact temperature measurement methods at present. It has the advantages of fast response, wide measurement range and high sensitivity, so it is widely used in various industries. When the infrared thermometer is used for body temperature detection, its measurement temperature range should be between 24.0°C and 45.0°C, and the accuracy requirement is ± O. 1°C. However, even if the infrared thermometer currently used has an accuracy index of 1%, it is far from meeting the accuracy requirements for measuring body temperature. In addition, within the temperature range of 24.0°C to 45.0°C, the measurement accuracy of the infrared thermometer is easily affected by the external ambient temperature, resulting in an increase in the measurement error. At the same time, the accuracy and stability of the infrared thermometer are easily affected by the external environment temperature. Therefore, it is of great significance to reduce the influence of external environmental factors on infrared thermometers.
Aiming at the current status of medical infrared thermometers, this subject proposes a new compensation method for ambient temperature on the basis of consulting a large number of domestic and foreign literature. This method is based on the working principle of the pyroelectric detector, taking the difference between the measured object and the ambient temperature as a reference, and determining the amount of compensation according to the difference. Through digital temperature measurement: take up the chip to measure the ambient temperature, and use software compensation to avoid the shortcomings of using thermistors in the past.
In the infrared temperature measurement system, the infrared signal is converted into a pulse signal with a frequency of 20 Hz after being converged by the optical system, modulated by the chopper and received by the pyroelectric detector. This signal is amplified, filtered, shaped and A/D converted into a digital signal, and then sent to the microcontroller for data processing, compensation and display.
In the design process of the system, use Wave6000 single-chip computer simulation system to debug the single-chip computer. In order to maintain the correct timing relationship between each part, the software is all written in assembly language. The calibration and testing of the system show that the accuracy and stability of the system have been improved.
