What is "field of regard"

n. all of the points of the physical environment that can be perceived by a stable eye at a given moment [syn: visual field, field of vision]

The field of regard (abbreviated FOR) is the total area that can be captured by a movable sensor. It should not be confused with the field of view (FOV), which is the angular cone perceivable by the sensor at a particular time instant. The field of regard is the total area that a sensing system can perceive by pointing the sensor, which is typically much larger than the sensor's FOV. For a stationary sensor, the FOR and FOV coincide.