Target size and optical resolution of dual color infrared thermometer

Target size and optical resolution of dual color infrared thermometer

Target size of dual color infrared thermometer

Infrared thermometers can be divided into monochromatic thermometers and bichromatic thermometers (radiation colorimetric thermometers) based on their principles. For a monochromatic thermometer, when measuring temperature, the area of the measured target should fill the field of view of the thermometer. It is recommended that the size of the tested object exceed 50% of the field of view. If the target size is smaller than the field of view, the background radiation energy will enter the visual sound symbol of the thermometer to interfere with the temperature measurement reading, causing errors. On the contrary, if the target is larger than the field of view of the thermometer, the thermometer will not be affected by the background outside the measurement area.

For a dual color thermometer, its temperature is determined by the ratio of radiation energy within two independent wavelength bands. Therefore, when the measured target is small, not filled with the scene, and there is smoke, dust, or obstruction on the measurement path that attenuates the radiation energy, it will not affect the measurement results. Even with energy decay of 95%, the required temperature measurement accuracy can still be guaranteed. For targets that are small and in motion or vibration; Sometimes targets that move within the field of view, or may partially move out of the field of view, using a dual color thermometer is a good choice under these conditions. If it is impossible to directly aim between the thermometer and the target, and the measurement channel is bent, narrow, or obstructed, a dual color fiber optic thermometer is the best choice. This is due to its small diameter, flexibility, and ability to transmit radiation energy through curved, obstructed, and folded channels, making it possible to measure targets that are difficult to access, under harsh conditions, or close to electromagnetic fields.

Optical resolution of dual color infrared thermometer

The optical resolution (distance and sensitivity) is determined by the ratio of D to S, which is the ratio of the distance D between the thermometer and the target to the diameter S of the measuring spot. If the thermometer must be installed away from the target due to environmental conditions, and to measure small targets, a high optical resolution thermometer should be selected. The higher the optical resolution, i.e. increasing the D: S ratio, the higher the cost of the thermometer.