Thermal Image

A thermal image is a visual representation of the infrared radiation emitted by objects within the field of view of an infrared camera or thermal imaging device. This radiation is converted into a visible image, where different temperatures are represented by varying colors or shades of gray. A thermal image is also often referred to as a thermogram.

The colored contrast allows for the identification of temperature variations and heat patterns across the observed scene. Color palettes, tailored to specific applications, are used to improve visual interpretation. Popular color palettes include the iron, rainbow, and grayscale palettes.

The iron palette is the most common, displaying the coldest areas in black, slightly warmer areas in blue/purple, mid-range temperatures in red/orange/yellow, and the hottest temperatures in white. This palette provides a clear visual representation of temperature gradients.

The black-and-white palette, also known as grayscale, shows details very well by displaying a range from black to white through multiple shades of gray. Due to its high detail resolution, this palette is commonly used in night vision or security cameras, but it is less effective for machinery imaging as it makes distinguishing temperature variations more challenging.

The rainbow palette excels at showing thermal sensitivity by representing temperature differences with a wide range of colors. Similar to the iron palette, it uses an extensive color range to indicate greater temperature variation, making it particularly effective for highlighting subtle temperature changes.

Advanced radiometric imaging systems can also provide quantitative temperature data for each pixel, enabling precise thermal analysis and measurement.