Understanding Infrared Thermography Reading 7 Part 2 of 2.pdf

A.4.2 Scanners and Imagers.Qualitative and Quantitative
The parameters used for assessing the performance of infrared thermal
imaging scanners are complex and the methods used for testing performance
have generated some controversy among manufacturers and users of these
instruments. A thermal image is made up of a great number of discrete point
measurements, however, many of the performance parameters of infrared
thermal imagers are the same as those of radiation thermometers (pointsensing
infrared radiometers that read out in temperature). Others derive from,
or are extensions of, radiation thermometer performance parameters.
Qualitative (non-measuring) thermal imagers, also called thermal viewers,
differ from quantitative (measuring) thermal imagers, also called imaging
radiometers, in that thermal viewers do not provide temperature or thermal
energy measurements.
It should be noted, therefore, that for users requiring qualitative rather than
quantitative thermal images, many of the parameters discussed herein are of
no importance.
Charlie Chong/ Fion Zhang