(1) Performance indicators such as temperature range, spot size, working wavelength, measurement accuracy, response time, etc.; environment and working conditions, such as ambient temperature, window, display and output, protection accessories, etc.

(2) Determine the temperature measurement range The temperature measurement range is one of the most important performance indicators of the thermometer. Each model of thermometer has its own specific temperature range. Therefore, the user's measured temperature range must be considered accurate and comprehensive, neither too narrow nor too wide. According to the law of black body radiation, the change of radiation energy caused by temperature in the short waveband of the spectrum will exceed the change of radiation energy caused by the emissivity error. Therefore, the short wave should be used as much as possible when measuring temperature.
(3) Determine the target size According to the principle, infrared thermometers can be divided into monochromatic thermometers and dual-color thermometers (radiation colorimetric thermometers). For monochromatic thermometers, when measuring temperature, the area of ​​the target to be measured should fill the field of view of the thermometer. Conversely, if the target is larger than the thermometer's field of view, the thermometer will not be affected by the background outside the measurement area.