FLIR ThermaCAM P45 User Manual page 186

21 – The measurement formula
10400703;a2
21
Figure 21.4 Relative magnitudes of radiation sources under varying measurement conditions (LW camera).
1: Object temperature; 2: Emittance; Obj: Object radiation; Refl: Reflected radiation; Atm: atmosphere
radiation. Fixed parameters: τ = 0.88; T = 20 °C (+68 °F); T = 20 °C (+68 °F).
refl atm
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Publ. No. 1557966 Rev. a155 – ENGLISH (EN) – February 6, 2006