Operational visual requirements define what a controller must be able to see, and at what quality, through a remote tower's camera system to safely provide air traffic services. They translate the out-the-window standard into measurable camera-and-display performance.
These cover resolution, field of view, the ability to detect and identify aircraft and vehicles at required ranges, low-visibility and night performance, and how pan-tilt-zoom and infrared augment the panoramic view. They are a central part of the FAA's technical requirements for Remote Tower Systems.