SWIRBilder

SWIRBilder, or short-wave infrared imaging, refers to images captured in the short-wave infrared portion of the spectrum, approximately 1.0 to 2.5 micrometers. These images are produced by cameras that use SWIR-sensitive detectors, most commonly indium gallium arsenide (InGaAs). Some systems extend into about 2.6 micrometers with specialized materials, and others use detectors such as mercury cadmium telluride (MCT) for longer wavelengths. Because standard silicon cameras do not respond to SWIR, SWIR cameras are typically cooled to reduce dark current and noise, though uncooled variants exist.

Imaging can be passive, relying on ambient SWIR illumination (for example daylight), or active, using infrared LEDs or lasers to illuminate the scene. SWIR imaging exploits material reflectance in this band; many substances show distinctive SWIR signatures, and SWIR can reveal contrast not visible in the visible spectrum. In addition, SWIR light penetrates fog, smoke, and haze better than visible light, and can reveal through some camouflage or scattering conditions.

Applications include security and surveillance, automotive and aviation for night vision and driver assistance, and industrial inspection and process control (such as polymer, glass, and coating inspection). SWIR imaging is also used in electronics and solar cell inspection, agriculture and vegetation monitoring, and mineralogical or archaeological studies where material contrast in the infrared is informative.

Limitations involve higher cost and limited availability compared with visible cameras, the need for cooling and calibration, sensitivity to atmospheric absorption in certain bands, and the requirement for illumination in low-light scenes. Recent developments include higher-resolution uncooled InGaAs sensors, multispectral SWIR imaging with filter wheels, and greater integration into mobile and embedded platforms.