Those tiny red lights you see on CCTV cameras are not always indicators that the camera is recording, they are infrared (IR) LEDs that help cameras capture footage in the dark.
In low-light or completely dark conditions, a CCTV camera cannot rely on visible light to produce clear images. This is where infrared technology becomes essential. Infrared light lies just beyond the visible spectrum, meaning it cannot be seen by the human eye. These IR LEDs emit infrared light, which reflects off objects and is detected by the camera’s sensor, allowing it to record clear footage, usually in black and white.
The process is largely automatic. A Light Dependent Resistor (LDR) or built-in sensor detects the amount of ambient light and helps the camera switch between day and night modes. During the day, when there is sufficient light, the infrared LEDs remain off. As light levels drop, the sensor activates the IR LEDs.
This seamless transition ensures the camera continues to function effectively without manual intervention, maintaining clear surveillance even in complete darkness.
(Got a science query, a story or a nerdy joke? Write to us at xplore.science @newindianexpress.com)