Thermal cameras measure the intensity of infrared radiation reaching the camera from different angles to create a thermographic image, also called a thermogram. This infrared radiation can come from different sources.
Warmer objects typically emit more infrared radiation. How much they generate for a certain temperature is defined by their emissivity.
The air itself generates infrared radiation. The warmer it is, the more radiation will be captured by the camera.
Objects can reflect radiation. Solar panels for example reflect some of the radiation coming from the air and can reflect radiation coming from neighbouring panels or building as well.
The camera itself generates infrared radiation. As it heats up by the sun, or cools down by wind, the measurements of the camera will change.
A radiometric camera keeps track of the intensity of infrared radiation captured in each pixel and offers a lot of functionality to take into account the different effects mentioned above. This allows you to get accurate temperature measurements of the objects you're scanning without getting too much interference from other sources.
When results are delivered non-radiometrically it means they don't offer accurate temperature measurements. Problems can be detected and analysed visually, but you don't have a lot of information about their severity. In some cases, comparisons can be made between different problems in the same scan, but it's hard to know what the impact is of some of the problems highlighted above.
Different types of anomalies can be detected of course, which allows you to spot some of the most important problems like string issues, bypassed substrings and severe hotspots.
Faint anomalies like PID or emerging hotspots are a lot harder to spot. It's also not possible to gain insight into the delta temperature of a hotspot, making it hard to compare them with other hotspots in the same inspection, or with detections made at a different point in time. Even if you manage to detect them, you thus can't properly evaluate if they're becoming worse.
When results are delivered radiometrically it means they offer accurate and absolute temperature measurements. This means you have information about the temperature of the scanned object at that point in time, enabling better severity classification and loss estimation.
Min, max, mean and delta temperatures are available for all anomalies (if applicable) and can be used to compare anomalies within the same inspection and across inspections. Proper normalisation to Standard Test Conditions (STC) is possible and in conjunction with the digital thread, the results can be used for advanced time-based analysis.
Panels with hotspots showing increasing normalised delta temperatures are degrading and should be addressed before they become serious safety risks or start generating considerable damage and losses.
The severity, estimated loss, remedial action and thermal information are only available on all anomalies when data is delivered radiometrically.
The thermal ranges are only available when data is delivered radiometrically.