Finding The Emissivity Of An Object; Using A Thermocouple; Using Reference Emissivity; Reflected Temperature - FLIR ThermaCAM E4 Operator's Manual

15.3 – Reflected temperature
15.2.1

Finding the emissivity of an object

15.2.1.1

Using a thermocouple

Select a reference point and measure its temperature using a thermocouple. Alter
the emissivity until the temperature measured by the camera agrees with the ther-
mocouple reading. This is the emissivity value of the reference object. However, the
temperature of the reference object must not be too close to the ambient temperature
for this to work.
15.2.1.2

Using reference emissivity

A tape or paint of a known emissivity should be put onto the object. Measure the
temperature of the tape/paint using the camera, setting emissivity to the correct
value. Note the temperature. Alter emissivity, until the area with the unknown emis-
sivity adjacent to the tape/paint has the same temperature reading. The emissivity
value can now be read. The temperature of the reference object must not be too
close to the ambient temperature for this to work either.
15.3

Reflected temperature

This parameter is used to compensate for the radiation reflected in the object and
the radiation emitted from the atmosphere between the camera and the object.
If the emissivity is low, the distance very long and the object temperature relatively
close to that of the reflected it will be important to set and compensate for the reflect-
ed temperature correctly.
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Publ. No. 1 558 017 Rev. a62 – ENGLISH (EN) – August 19, 2004