I. Introduction
Traffic light recognition (TLR) systems can be used for various purposes. Depending on the application, different requirements are set. In the case of advanced driver assistance systems (ADAS), a traffic light detection can be used purely informatively in order to assist the driver or actively intervene, e.g., in case of potentially running a red light. With the continuous development in the area of automated driving, the requirements further increase since no errors can be tolerated or at least the system has to be able to detect potential difficulties. Besides ADAS, a TLR system can contribute to energy-efficient driving by an early recognition of upcoming traffic lights.