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Dense fog can obscure everything, making it difficult to see even a few feet ahead. This might seem like an opportune moment for theft—unless you have SWIR camera surveillance in place. Unlike visible light, which struggles to penetrate water vapor, SWIR (Short Wave Infrared) light excels in such conditions, providing high-resolution images where human vision fails. Let’s delve into the mechanics and advantages of SWIR camera surveillance.
SWIR, short for short wave infrared, operates in the wavelength range of 0.9 to 1.7 microns. Similar to visible light, SWIR photons are absorbed and reflected by objects, enabling high dynamic range and excellent contrast in imaging. However, SWIR light is invisible to the naked eye, and standard silicon sensors used for visible light imaging can’t detect it. Instead, SWIR cameras use specialized sensors made from materials like InGaAs (Indium Gallium Arsenide) or MCT (Mercury Cadmium Telluride).
SWIR illumination can light up an industrial area at night while maintaining the appearance of darkness. Outdoors, natural SWIR, known as ‘night glow,’ is present in nearly all weather conditions, both day and night.
Night glow, a form of atmospheric radiance, enables SWIR camera surveillance to function effectively even in the darkest conditions.
SWIR camera surveillance stands out for its ability to provide clear images in conditions where visible light fails. The shorter wavelength of SWIR light compared to visible light means it isn’t scattered by fog and smoke particles. This makes SWIR imaging highly effective in such environments. Unlike thermal imaging, which can be disrupted by heat haze and temperature variations, SWIR imaging remains unaffected.
This makes SWIR ideal for clear imaging at any time of day and under various atmospheric conditions.
The benefits of SWIR camera surveillance extend beyond just penetrating fog and smoke. One key advantage is that it requires no visible illumination. A strong SWIR light beam can illuminate an area that appears dark to conventional imaging systems. SWIR sensors can also detect lasers and beacons, useful for tracking mobile teams or for military IR laser spotting and tracking.
In biometrics, SWIR technology can differentiate between real and fake hair, aiding in identifying individuals attempting to disguise their identity. Human hair appears light, while synthetic hair shows up dark, making it easy to spot a wig.
SWIR imaging relies on InGaAs sensors, capable of detecting light from 550nm to 2.5μm. An alternative is MCT sensors, which can detect into the long wave infrared (LWIR) region. MCT sensors are tunable, allowing adjustments based on cadmium concentration for optimal absorption in a specific region. However, they require cryogenic cooling, which is a significant limitation.
SWIR radiation can pass through glass similarly to visible light, meaning standard camera lenses, mirrors, and other optics can be used in SWIR cameras. Upgrading to a SWIR surveillance system might require only minor adjustments to existing setups.
At Shanghai Optics, we specialize in creating custom optics to meet your specific performance needs. Whether you require a high-frame-rate SWIR camera, a SWIR vision system for unmanned vehicles, or SWIR imaging equipment for research, we have the expertise to assist you. We provide optical components and lens assemblies tailored to your requirements. Share your needs with us, and we’ll develop a customized solution for you.
With SWIR camera surveillance, fog and darkness are no longer obstacles to maintaining security. Embrace the clarity and reliability of SWIR imaging for your surveillance requirements.
Contact Shanghai Optics today! We’d be more than happy to discuss your projects and how to best bring them to fruition.