Thermal Imaging

The best thermal-imaging devices allow you to see and measure temperature differences accurately from a safe distance. They are useful for identifying heat sources in very dark or obscured places, whether you’re trying to rescue a lost person or pet, to identify sources of heat loss from a house or to observe a variety of wildlife, including birdwatching.  More recently thermal imaging cameras have even been effectively used to identify infected individuals in a crowd, by picking out those that have higher feverish temperatures. 

An infra-red thermal camera will enable you to explore your environment in a unique way. Beyond the visible spectrum, there is an unseen world of heat radiation. For the most part, the cameras work like regular ones, except that image sensor detects invisible IR light and it is translated to a visual “thermogram.” Thermal cameras still have pixels, but starting at lower resolutions (e.g. 80x60 pixels, or 0.003 megapixels). This is enough detail to pick out hotspots in wiring, for example, but higher resolutions are always better, especially for thermal imaging at a distance, such as search and rescue, or wildlife observation. 

What do Thermal Imaging Device Specifications Mean?

Thermal Sensor Size – Similar to digital cameras, thermal sensors are measured in pixels; generally speaking, the bigger the sensor the better the picture, as a larger sensor can capture more detail. Pulsar thermal imagers use one of three different sized sensors with its own designation: XM models use a 320×240 thermal sensor, XQ models use a 384×288 thermal sensor, and XP and XG models use a 640×480 thermal sensor.

Thermal Sensor Pixel Pitch – This is the distance between the centre of the pixels. A smaller pixel pitch results in finer image quality and a physically smaller thermal sensor. However, a larger pixel offers more sensitivity. A sensor with a smaller pixel pitch will have a greater base magnification than a thermal imager with the same size lens and a greater pixel pitch. Pulsar XM & XG sensors have a 12µm pixel pitch, and XQ and XP sensors have a 17µm pixel pitch.

NETD – Noise Equivalent Temperature Difference (NETD) is a measurement of the smallest temperature difference a thermal device can detect. The lower the value, the more sensitive the device becomes — performing better than a device with a greater NETD value in conditions that are challenging to thermal imagers such as cold, fog, and rain. A device’s NETD rating is an important indicator as to how well it will perform.

Refresh Rate – A high refresh rate (such as 50Hz) is best when choosing a thermal imager. A high refresh rate will result in a smooth image when panning or tracking fast-moving objects.

Tring Astronomy Centre stock and supply a wide range of Thermal imaging and Night Vision Devices from trusted brands such as Guide Sensmart, Pulsar and Zeiss and are happy to offer advice.