Giving. Here, linear system theory provides insights into whether and in what form pre-processed data reaches the central processing of our brain. These insights are crucial for determining the limits of our visual perception and ultimately for understanding the function of the entire system. Recognizing the importance of a system-theoretical description of the visual system at an early stage is the achievement of Prof. Dr. Ing. Dr.-Ing. E.h. H. Marko, the emeritus holder of the Chair of Communication Engineering at the Technical University of Munich. It is also thanks to his significant initiative that cybernetics, along with the study of the visual system as a field of teaching and research, was established at the Technical University of Munich. His initiative also led to the founding of the special.