What is a thermal imager? Let’s dive into the science behind thermal imagers and the invisible world of heat they allow us to see.
What is a Thermal Imager? How does a thermal imager work?
A thermal imager is a non-contact device that detects infrared energy (heat) and converts it into a visual image.
Thermal imagers detect infrared waves, not visible light.
The first thing you need to know about thermal cameras is that they don’t work the same way as regular cameras. Conventional daylight cameras and the human eye work on the same basic principle: visible light energy hits something, reflects off of it, a detector picks up the reflected light, and then converts it into an image.
Thermal imagers create images from heat, not visible light. Heat (also called infrared or thermal energy) and light are both parts of the electromagnetic spectrum, but a camera that can detect visible light will not see thermal energy, and vice versa. Thermal cameras capture infrared energy and use the data to create images through digital or analogue video outputs.
Inside a Thermal Imager: What It Consists Of
A thermal imaging camera consists of a lens, a thermal sensor, electronics, and a mechanical housing. The lens focuses infrared radiation onto the sensor. The sensor can have different pixel configurations: from 80 × 60 to 1280 × 1024 pixels and more. This is the camera resolution.
This resolution is low compared to visible light thermal imagers because thermal detectors need to sense energy that has a much longer wavelength than visible light, which requires each sensor element to be much larger. As a result, thermal cameras typically have a much lower resolution (fewer pixels) than visible sensors of the same mechanical size.
Important features to consider when choosing a thermal imaging camera are resolution, range, field of view, focus, thermal sensitivity, and spectral range. Click to learn more.
What Can Thermal Cameras Detect?
The heat perceived by an infrared camera can be measured very accurately, which makes it suitable for a wide variety of applications. A thermal imaging camera can detect tiny differences in temperature – as small as 0.01°C – and display them as shades of grey or different color palettes.
Everything we encounter in our daily lives emits heat energy – even ice. The hotter an object is, the more heat it emits. This radiated heat is called a “thermal signature”. When two objects that are close to each other have even subtle differences in thermal signature, they are clearly visible to the thermal sensor regardless of the lighting conditions. This allows thermal imagers to see in complete darkness or in smoky environments.
Thermal imaging cameras can see many things that our eyes or conventional cameras cannot see but can be blocked by some materials.
What Are Thermal Imagers Used For?
We have learnt what is a thermal imager. Thermal imaging and night vision technologies are often confused, but each has its own unique features and strengths.
The potential applications for thermal imaging cameras are almost endless. Originally developed for surveillance and military operations, thermal cameras are now widely used for building inspection (humidity, insulation, roofing, etc.), firefighting, autonomous vehicles and automatic braking, skin temperature screening, industrial inspections, scientific research, and much more.