An infrared thermal imager is a non-contact device that detects infrared energy (heat) and converts it into a visible light image. Let us delve into

the scientific principles of infrared thermal imagers and the invisible world we can see with their help. Capturing Infrared Waves, Not Visible Light First, it is essential to understand that an infrared thermal imager works differently from an ordinary camera. Ordinary visible-light cameras

operate on the same basic principle as the human eye: visible light energy strikes an object, reflects back, and the detector receives the reflected

light and converts it into an image. Thermal imagers produce images using heat rather than visible light. Heat (also known as infrared energy or thermal energy) and light are both

parts of the electromagnetic spectrum, but a camera that detects visible light cannot sense thermal energy, and vice versa. A thermal imager

captures infrared energy and generates an image from data output as digital or analog video. Internal Structure of a Thermal Imager A thermal imager consists of a lens, a thermal sensor, processing electronics, and a mechanical housing. The lens focuses infrared energy onto

the sensor. Sensors are available in various pixel resolutions, ranging from 80×60 up to 1280×1024 pixels and beyond. This defines the resolution

of the thermal imager. Thermal imagers have lower resolution compared to visible-light cameras because thermal detectors must sense energy with wavelengths

much

longer than visible light, which requires each sensing element to be significantly larger. As a result, thermal imagers have much lower

resolution

(fewer pixels) than visible-light sensors of the same physical size. Important parameters to consider when selecting an infrared thermal imager include resolution, range, field of view, focusing, thermal

sensitivity, and wavelength range. What Can a Thermal Imager Detect? The heat sensed by an infrared thermal imager can be measured with extremely high precision, giving thermal imagers a wide range of

applications. Thermal imagers can detect subtle temperature differences — as precise as 0.01°C — and display them in grayscale or using

various color palettes.

Everything we encounter in daily life emits thermal radiation — even ice. The hotter an object is, the more infrared radiation it emits.

The thermal energy of this radiation is referred to as a "thermal signature". If two adjacent objects have subtle differences in their thermal

signatures, they will appear very clearly to thermal sensors regardless of lighting conditions. This allows thermal imagers to detect targets in

complete darkness or smoky environments. Thermal imagers can detect many things invisible to the human eye or undetectable by ordinary cameras, yet they can be blocked by some

unexpected materials. What are the applications of thermal imagers? The potential uses of thermal imagers are nearly limitless. Originally developed for surveillance and military operations, thermal imagers

are now widely used for building inspections (moisture, insulation, roofing, etc.), firefighting, autonomous vehicles and automatic braking, body

temperature screening, industrial testing, scientific research, and much more.