TDN (True Day/Night) technology supports night vision capability by implementing a physical ICR that is removed by a mechanical motor.
DDN (Digital Day/Night) technology allows for viewing in both day and night conditions, without the use of a ICR. As light diminishes below a certain level, DDN technology switches color image to black and white image to offer similar benefits to TDN with a lower cost. At night, the captured image depends on the lighting and infrared waves off objects.