NIRSWIRcameras

NIR/SWIR cameras image infrared radiation in the near-infrared (NIR) and short-wave infrared (SWIR) bands. NIR typically covers about 0.75 to 1.4 micrometers, while SWIR covers roughly 1.4 to 3.0 micrometers. They can operate in conditions where visible cameras struggle, such as low light or through certain obscurants, and are often used with illumination or scene-dependent contrast. They are distinct from thermal cameras that image longer-wavelength emitted heat.

Most NIR/SWIR cameras use indium gallium arsenide (InGaAs) detectors, which provide sensitivity across roughly 0.9 to 2.6 micrometers in extended-range variants. Silicon-based sensors do not detect beyond about 1 micrometer. InGaAs cameras come in cooled and uncooled forms; cooling (thermoelectric, liquid, or Stirling) reduces dark current and noise, enabling longer exposures and higher sensitivity in low light and longer wavelengths. Detector formats range from hundreds of thousands to several megapixels, with common arrays at 640×512 or 1280×1024.

Specialized optics and window materials are used to transmit SWIR light, including zinc sulfide, zinc selenide, and sapphire. Performance is influenced by spectral band choice, dark current, read noise, frame rate, and dynamic range. Some systems include on-board processing and interfaces suitable for scientific, industrial, or machine-vision pipelines.

Applications for NIR/SWIR cameras include security and surveillance, industrial inspection (such as semiconductor wafers and solar cells), machine vision in challenging lighting, agriculture, astronomy, and search-and-rescue. The field is evolving toward broader spectral coverage, higher resolution, reduced cost, and advances in detector materials and cooling technologies.