Definition and characteristics of SWIR lens

The SWIR lens is used to capture images of day and night scenes. The imaging effect is black and white, with strong penetration, and can be imaged under the invisible condition of the human eye. It can normally work under visible light in the daytime, and the short-wave infrared lens can play its advantages in the night or smoke, fog, and other situations, and can see the active image as clearly as in the daytime, which has long been separated from the use of traditional night vision technology.

Here is the content list:

●Definition of SWIR lens

●Features of SWIR imaging

●The image of SWIR lens

Definition of SWIR lens

Light is an electromagnetic wave. 0.38-0.76um is the visible spectral region, and 0.76-1000um is the infrared spectral region; The part of 0.76-3.0um is called reflected infrared light, and the part of 3.0-18um is called emitted infrared light. The short-wave infrared light SWIR is located in the non-visible light spectrum between the near-infrared (NIR) and the long-wave infrared (IR), about 0.9-1.7um, and its effect is similar to that of photons in the visible light range; It behaves more like visible light than thermal energy in the infrared spectrum. Although SWIR wavelength is relatively short, photons in this range are not easily affected by Rayleigh scattering caused by particles of smaller diameter, because their wavelength is relatively long, which means that SWIR light can penetrate smoke, fog, or haze.

Features of SWIR imaging

1. High recognition: SWIR imaging is mainly based on the principle of target-reflected light imaging. Its imaging features are similar to visible light gray image features, with high imaging contrast, and clear target details. In target recognition, SWIR imaging is an important supplement to thermal imaging technology;

2. All-weather adaptation: SWIR imaging is less affected by atmospheric scattering, has a strong ability to penetrate smoke, fog, or haze, and has a long effective detection range. Its adaptability to climate conditions and battlefield environment is significantly better than visible light imaging;

3. Low-light night vision: under the night vision condition of atmospheric glow, photon irradiance is mainly distributed in the SWIR band range of 1.0-1.8um, which makes SWIR night vision imaging have significant congenital advantages compared with visible light night vision imaging; It can extract image details from deep shadows and can penetrate the window glass for imaging, especially suitable for use in dark places or at night.

4. Stealth active imaging: In the 0.9-1.7um band, the military laser light source technology is mature (1.06um, 1.55um), which makes SWIR imaging have significant comparative advantages in the application of stealth active imaging;

The image of SWIR lens

Compared with MWIR and LWIR, SWIR has a shorter wavelength and more intuitive imaging features. Unlike low-resolution infrared thermal imaging, SWIR can generate high-resolution images with strong contrast. The imaging contrast of SWIR, MWIR, and LWIR is as follows.

Compared with visible light, passive SWIR imaging is similar to visible light imaging. It uses the reflected light of the target object rather than the thermal radiation of the target object. However, SWIR has a longer wavelength and different interaction with the atomic structure, which also provides some new and unique imaging visual applications.