A backup camera is a video camera specifically designed to be attached to the rear of a vehicle to aid in reversing and reduce the rear blind spot. The rear blind spot has been described as a "killing zone" due to the accidents it contributes to. Backup cameras are usually connected to the vehicle's head unit display. A common variant is a surround-view system, which assembles a synthetic but positionally accurate top-down view of the vehicle and its surroundings.