31.2.1 Finding the emissivity of a sample
31.2.1.1 Step 1: Determining reflected apparent temperature
Use one of the following two methods to determine reflected apparent temperature:
31.2.1.1.1 Method 1: Direct method
Look for possible reflection sources, considering that the incident angle = reflection angle (a
= b).
10588903;a1
Figure 31.1 1 = Reflection source
1
If the reflection source is a spot source, modify the source by obstructing it using a piece if
cardboard.
10589103;a2
Figure 31.2 1 = Reflection source
2
Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 161
31 – Thermographic measurement techniques