Understanding Infrared Thermography Reading 3

132. Transfer calibration - A technique for correcting a temperature measurement or a
thermogram for various errors by placing a radiation reference standard adjacent
to the larget.
133. Transfer standard - A precision radiometric measurement instrument with NTST
traceable calibration used to calibrate radiation reference sources.
134. Transmissivity, (transmiUance) (τ) - The proportion of infrared radiant energy
impinging on an object's surface, for any given spectral interval thai is
transmitted through the object. (τ = 1 – Ɛ - ρ) For a blackbody. transmissivity τ =
O. Transmissivity is the internal transmittance per unit thickness of a nondiffusing
material.
135. Two-color pyrometer - See ratio pyrometer.
136. Unity - One (1.0).
137. Valley hold - A feature of an instrument whereby an output signal is maintained
at the lowest inslantaneous measurement for a specified duration; opposite of
peak hold.
138. Working distance – The distance from the target to the instrument, usually to the
primary optic.
139. Zone - In line scanners. a scanned area created by the transverse linear motion
of the product or process under a measurement sector of the scanner.
Charlie Chong/ Fion Zhang