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An in-depth explanation about 'ambient temperature' and 'reflected temperature' parameters

Some questions we are frequently asked by our customers and distributors are: "What’s the difference between the ‘Ambient Temperature’ and ‘Reflected Temperature’ in measurement parameters, and in what situation should we adjust these parameters?"

We are here to answer them once and for all.

Both of the parameters are adjustments the thermal imager makes on its temperature calculation. Thermal imagers measure an object’s temperature based on infrared radiation emitting from the object's surface. However, it is often the case where the infrared signals imagers pick up are mixed with interference signals from the environment. Two major sources of interference are thermal radiation from the ambient environment and the reflection of nearby strong infrared sources off of the measured object’s surface.

The ‘Ambient Temperature’ parameter accounts for infrared radiation bouncing off of the object’s surface from every other object in the environment. All objects with a temperature above 0 kelvin emit thermal radiation. And the higher the temperature, the more intense the radiation. Since the influence of ambient radiation is ubiquitous, users should always be mindful of their ‘Ambient Temperature’ setting, because the ambient temperature’s relationship to the measured object’s temperature also affects how emissivity compensates for temperature calculation in the thermal imager.

The default setting for the parameter is 20°C. However, ideally, users should always adjust it based on the actual ambient (air) temperature. This parameter re-adjustment is particularly important for applications like inspecting solar panels in deserts and substation inspections during winter time.

The ‘Reflected Temperature’ parameter is only applicable when there is a strong infrared radiation source in the measured object’s vicinity. It’s particularly necessary when the interested object has relatively low emissivity. The thermal imager can adjust its calculation based on the ‘equivalent temperature of the reflected radiation’ source and properly display the interested object’s temperature based on its own emission.

Ideally, during an inspection, if there is an unwanted interfering heat source nearby, the best solution is to shield the measured object from the radiation. If shielding or coating the object or its interfering source is impractical, please consult a thermographer on how to set the ‘equivalent temperature of reflected radiation’. FOTRIC will also release an educational video on how to measure the ‘equivalent temperature of reflected radiation’ shortly.

Here at FOTRIC, we strive to listen to our customers’ needs and solve their pain points. If you have any questions or suggestions for us, please don’t hesitate to reach out and make yourself heard at or"


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