Tuesday, September 15, 2015

Analyze your findings…..How accurate are your readings and why?

Many people are not aware that the detector in an infrared camera actually only reads electromagnetic radiation it receives in a specific range of wavelengths. In order to display this in a useful reading the camera makes several calculations in order to convert the actual data to a temperature. The emissivity and transmissivity (sometimes depending on the camera manufacturer) have to be manually entered into the camera’s menu. if this value is entered incorrectly the actual temperature will be exponentially different (see Stefan-Boltzmann’s Law) than the displayed temperature. The old saying of “well as long as it is consistently wrong the change will be noted” is not entirely correct either, as the difference between phases will also be exponentially wrong. The error is going to be worse as the temperature rises – if the differential between the measured temperatures is significant then the displayed temperatures could be significantly different!

So that phase imbalance that looks like it is only a couple of degrees different could actually be upwards of 30 degrees! The visual setup of the camera could be the only other way of determining the severity of a potential defect. As anyone who has spent some time looking through a camera will tell you the visual component can be significantly altered (both to make things look better than they are as well as to show “elevated” differentials.) Depending on the level, span and range setup on the camera it would be very easy to miss a severe problem.

With this in mind it is easy to see why there are so many infrared problems that aren’t caught. In order to ensure that our customers “See What You’ve Been Missing”, all IRISS polymer based windows utilize the same grade and thickness of polymer, so that if you have correctly setup your camera for one IRISS window you can know without any doubt that it is “calibrated” for all IRISS windows. Our Fixed And Stable Transmission (FAST) is exactly what the name implies – unchanging! The ambient temperature outside, length of time in the field, relative humidity or barometric pressure have no effect on transmission rate and therefore no effect on your readings!