Active infrared night vision is the most commonly used night vision solution for surveillance cameras. It relies on infrared fill light and infrared sensing imaging to deliver clear surveillance footage in pitch-dark environments. Its core working principle is as follows: when light is insufficient, the device automatically turns on infrared LED lights, which emit invisible infrared light to illuminate objects. The image sensor then captures the reflected infrared signals to form images, resulting in black-and-white footage at night. Equipped with an ICR (Infrared Cut Filter) switching function, the device supports automatic day and night mode switching. During the day, it filters out infrared light to ensure true-to-life colors; at night, the filter is removed to maximize the reception of infrared light and optimize night vision performance. The mainstream infrared wavelengths are 850nm and 940nm. The 850nm wavelength features longer illumination range and higher efficiency, with a faint red glow visible at close distances. The 940nm wavelength has no red glow at all and offers better concealment, making it ideal for indoor scenarios with high privacy requirements. Compared with starlight night vision and thermal imaging technologies, active infrared night vision is more cost-effective and performs better in completely dark conditions, serving as the mainstream choice for daily security surveillance.