Catergories

Accuracy describes how close an infrared thermometer reading is to the actual or reference temperature, while repeatability describes how consistently the instrument produces the same result under unchanged measurement conditions. Although both are important performance parameters, they represent different aspects of measurement quality. Understanding the difference helps users compare infrared thermometers, identify measurement errors, and improve measurement reliability.

Infrared thermometers determine surface temperature by detecting infrared radiation emitted by a target. Air, steam, smoke, dust, and other materials between the target and the instrument can affect how this radiation reaches the detector. Clean air normally has little effect over short distances, while dense steam, smoke, high humidity, suspended particles, and long measurement paths can introduce errors through absorption, scattering, and their own thermal radiation.

An infrared thermometer does not measure only the point indicated by the laser. Instead, it detects infrared radiation from a defined area within its optical field of view. As measuring distance increases, the measurement spot generally becomes larger. If the target is smaller than or close to the spot size, infrared radiation from the surrounding background can influence the reading. Understanding the relationship between target size, distance, and D ratio is essential for reliable infrared temperature measurement.