Thermal imaging
Thermal imaging works on the principle of detecting and capturing the infrared radiation emitted by objects. Every object with a temperature above absolute zero (-273.15 degrees Celsius) emits infrared radiation, which is invisible to the human eye.
Thermal imaging devices use a special lens to focus the infrared radiation onto a detector called a microbolometer. The microbolometer measures the temperature of each pixel in the image based on the amount of infrared radiation it receives. The detector then converts this temperature information into electrical signals.
These electrical signals processed by a signal-processing unit, which assigns different colors or shades to represent different temperatures. This processed information then displayed on a screen, creating a thermal image.
The colors or shades on the thermal image represent the different temperature levels of the objects in the scene. Warmer objects emit more infrared radiation and appear as brighter colors (such as red, yellow, or white), while cooler objects emit less infrared radiation and appear as darker colors (such as blue, purple, or black).
By analyzing the thermal image, users can identify temperature variations and patterns, which can help in various applications such as detecting heat leaks, identifying electrical malfunctions, locating people or animals in the dark, and detecting fires or hotspots in firefighting scenarios.
How thermal imaging works:
- Infrared Radiation: All objects with a temperature above absolute zero (-273.15 degrees Celsius or -459.67 degrees Fahrenheit) emit infrared radiation. The amount of radiation emitted depends on the object’s temperature.
- Infrared Detector: A thermal imaging device uses a special sensor called an infrared detector or microbolometer. This detector composed of an array of tiny elements that can detect and measure the intensity of infrared radiation.
- Lens and Optics: The thermal imaging device has a lens system that focuses the infrared radiation from the scene onto the infrared detector. The lens helps capture the thermal energy emitted by objects and directs it towards the detector.
- Infrared Detection: When the focused infrared radiation reaches the detector’s elements, each element absorbs the radiation and its temperature rises. This temperature change converted into an electrical signal.
- Signal Processing: The electrical signals from the detector are then processed by sophisticated electronics within the thermal imaging device. The device analyzes the intensity of the signals and assigns different colors or shades of gray to represent different levels of infrared radiation.
- Image Display: The processed signals are finally displayed on a screen, showing a visual representation of the detected thermal energy. The resulting image, often referred to as a thermogram, displays the variations in temperature across the scene.
- Interpretation: By observing the thermogram, users can identify and differentiate objects or areas based on their temperature differences. Warmer objects appear as brighter or lighter areas, while cooler objects appear darker. This allows for the detection of heat patterns, anomalies, or temperature gradients that may be invisible to the naked eye.