Thermal imaging via cooled detectors

The need to visualize thermal radiation is outlined. The characteristics of radiant energy and the transmission properties of the atmosphere are discussed to define the spectral range of interest. Practical methods of detecting thermal radiation are reviewed and the benefit of cooling the detector highlighted. Techniques whereby the detector can be made to interrogate the scene are described and contrasted. The manner by which the detected signal is processed is described with reference to several new electronic components. Finally some examples of present day systems are presented with examples of typical thermal imagery.