IR-Cut (Infrared-cut) filters are used in security cameras for producing accurate color images. However, an IR-cut filter helps to block the transmission of the infrared light and helps to pass the visible light. It is possible with the help of two optimal techniques: reflection or absorption.
Absorptive filters are made up of special glass that helps in absorbing near-infrared radiation. However, reflection filters are short-pass filters that help reflect infrared light with high efficiency.
Moreover, absorptive filters are most commonly used in CCD cameras, and the reflective IR filters are mostly used in CMOS cameras.
All the modern webcams and CCTV cameras come with a wide visible spectrum. They can see IR light to some extent. However, this light should be blocked for allowing the accurate reproduction of colors from the camera. During the day, a camera makes use of an IR-cut filter which helps to filter out the IR light. When the camera is working in the night mode, the IR-cut filter gets removed, which allows the sensitivity of a camera to reach down to 0.001 lux or lower.
What Does IR-Cut Do?
IR-cut is a mechanically designed shutter. It is present between the image sensors and the lens. It can be controlled by a motor or with the help of an electromagnet.
It is designed for blocking or delivering infrared light to create a true reproduction of colors to get a high-quality image during day and night time.
What is Infra-red?
Infra-red is known as radiant energy. It is electromagnetic radiation that has longer wavelengths than visible light. Human eyes can see light, which has a wavelength ranging between 320nm – 760nm.
Infrared ranges between 700nm to 1000nm on the electromagnetic spectrum. It is far more than what a human eye can see, and an IP camera can detect this light and use it to create images.
How IR-Cut Works?
IR filter is turned on during the day. It helps in blocking the infrared during daytime and only lets the visible light pass through. It ensures that image colors are not disturbed and generate a true representation of the human eye's colors.
The IR filter is turned off during the night or in low-light conditions. It helps IR and all other forms of light to reach the CCD/CMOS sensor. The image sensor can absorb enough light, and the camera can turn to black and white mode that is more sensitive to infrared light.