Ambient Temperature

Ambient temperature refers to the temperature surrounding the object being measured or the pyrometer/infrared camera. This temperature can affect infrared temperature measurement in two main ways. Firstly, it can influence the internal temperature of the device, which in turn affects the sensitivity of the detector, especially if the detector is also exposed to the ambient temperature and is not adequately insulated. The device’s firmware usually compensates for the influence of ambient temperature on the measured temperature value (referred to as the temperature coefficient), but it’s important to operate the infrared thermometer within its specified ambient temperature range.

Secondly, ambient temperature affects the measurement result when the object being measured has an emissivity of less than 1.000 and when ambient radiation reflected by or transmitted through the object significantly contributes to the overall radiation detected, compared to the temperature radiation of the object itself. Corrections are made to account for these radiation contributions and to compensate for an emissivity different from 1. It’s crucial to select the correct source for the ambient temperature in the device’s configuration. By default, the internal temperature of the infrared measuring device is assumed as an approximation for the ambient temperature, which is suitable for many scenarios. However, if the object’s ambient temperature significantly differs from the device’s temperature (e.g., in the case of measuring an object inside an oven through a viewing window), the actual ambient temperature needs to be set manually in the configuration or input via a communication interface.

In some cases, two different ambient temperatures must be considered, such as when measuring a partially transparent object where the ambient temperature in front of and behind the object differs. Additionally, when considering the influence of intense artificial radiation sources like radiant heaters or gas flames, it’s important to note that these sources are not blackbody radiators and have varying emissivity across different wavelengths. This means that the type of infrared thermometer used and the wavelengths it can detect should be considered when measuring temperature in the presence of these radiation sources.