What type of radiation do near IR cameras primarily detect?

Near infrared (IR) cameras primarily detect reflected radiation. These cameras are designed to capture specific wavelengths of light within the near-infrared spectrum, which range from about 700 nm to 1400 nm. Most commonly, near infrared imaging is used to see reflected light from objects rather than light emitted directly from their surfaces. This is significant in various applications, including surveillance, night vision, and agricultural monitoring, where detecting the reflected radiation provides valuable information about the material and its properties.

Understanding the nature of the detected radiation is crucial for interpreting the images produced by these cameras. Reflected radiation will vary based on factors such as surface texture, color, and material composition, all of which influence how an object reflects near infrared light. The ability to differentiate these characteristics is what makes near IR cameras effective in their respective uses.

The other types of radiation—such as emitted radiation, which comes from the thermal energy of an object, and radiation from chemical reactions—do not primarily characterize the operating principles of near IR cameras. In addition, while infrared radiation from heat sources is a crucial aspect of thermal imaging cameras, near IR cameras specifically rely on reflected radiation for capturing images.