Analysis of Thermal Imagers

• DOI: 10.1007/s10765-011-0932-z
• Publication Date: 2011-02-14T08:30:12Z
• Authors: Goran Grgić; Igor Pušnik
• Keywords: Microbolometer; Black-body radiation

A thermal imager with a microbolometer focal plane array (FPA) detector which does not require cooling is a relatively new type of instrument. With increasing use of thermal imagers for absolute temperature measurements, there is also an increasing need for their calibration. Five thermal imagers from three manufacturers were evaluated to identify parameters which affect their performance for accurate temperature measurements. Evaluation methods and measurements of parameters such as accuracy, temperature resolution, drift between internal calibration, non-uniformity, size-of-source effect, and distance effect are discussed. Based on the results, it is indicated which parameters should be evaluated in the calibration procedure as well as the uncertainty budget. The suitability of a blackbody for calibration was also addressed, especially in terms of dimensions related to the field of view of a thermal imager at the minimum focal distance.