The operation of all thermal imaging systems is based on the perception of the temperature differences between an object against a background and on the conversion of that difference to a visible image. Because all bodies are not heated up equally a picture of IR distribution appears.
The higher the difference between objects IR radiation intensity and the background’s IR radiation intensity the more resolvable and with better contrast the thermal image will be. Contemporary thermal imaging devices are capable of detecting temperature differences of 0.015-0.07°C.
How a Thermal Imager Works
- A special lens focuses the infrared light emitted by all of the objects in view.
- The focused light is scanned by the infrared detector elements creating electric impulses.
- The impulses are sent to a signal-processing unit that translates the information from the elements into data for the display.
- The signal-processing unit sends the information to the display, where it appears as various colours depending on the intensity of the infrared emission.
DETECTOR TYPES
There are two main detector types: cooled detector and uncooled detector.
Cooled Detector
Cooled thermal imagers technology implemented in cameras based on a detector that works at cryogenic temperature close to 77 degrees Kelvin (about -200°C) or lower.
Cooled detector is used to detect targets that have tiniest temperature change, long range, and high moving speed.
Cooler Detector Working Principles
Sensitive materials produce photoelectric effect by absorbing infrared radiation.
ADVANTAGES
- High sensitivity
- Long detection range
- Fast response
- Stable performance
DISADVANTAGES
- Working in cryogenic environment
- Relatively high-power consumption
- Expensive
Application – High-end fields such as aerospace, ships etc.
Cooler Detector Application
High-end fields such as aerospace, ships.
UNCOOLED DETECTOR
Uncooled thermal imagers technology implemented in detectors that work at ambient temperature range.
Uncooled detector is best choice for targets with short distance and not requiring very high-quality thermal imaging and affordable.
Working Principle
The thermal effect of infrared radiation is used to detect infrared radiation.
ADVANTAGES
Small size and light weight
Low power consumption
Long operating life
Working at room temperature
DISADVANTAGES
- Low sensitivity
- Short detection range
- Slow response
Application – Wide range of civilian and military applications.
Discover the essence of thermal imaging devices, rooted in detecting temperature variations and converting them into visible images. Modern thermal imagers detect temperature differences as low as 0.015-0.07°C, highlighting intricate details. These devices employ special lenses to focus infrared light emitted by observed objects, converted into electrical impulses by infrared detector elements. Cooled detectors, functioning at cryogenic temperatures, offer high sensitivity and long-range detection, suited for aerospace and high-speed targets. In contrast, uncooled detectors, operating at ambient temperatures, offer affordability and versatility for civilian and military applications despite lower sensitivity and shorter ranges. Explore the operational principles and applications driving thermal imaging technologies forward.