FLIR, an industry leader in thermal camera technology, has issued a .pdf file of information pertaining to technical requirements for correct thermal measurement and operation.
Commercial users of thermal cameras need to be aware of these technical parameters.
Note that thermal cameras are expensive compared to regular optical cameras. The low resolution thermal cameras, 160 by 120 (pixels), have limited professional use and targets often appear as blobs. Next are 320 by 240 cameras, and still higher the 640 by 480 models. The 640 by 480 cameras provide quite good image resolution, but may cost several times as much as cheaper models.