Instantaneous field of view (iFOV) is a term commonly used in the context of remote sensing, imaging systems, and optical instruments. It refers to the specific portion of a scene that an optical sensor or instrument can capture or observe at a given instant in time. In simpler terms, iFOV represents the angular extent of the scene that corresponds to a single pixel or detector element in the imaging system.
Key points related to iFOV include:
Angular measurement: iFOV is expressed in angular units, such as degrees or radians, and it defines the angle subtended by a single pixel or detector on the imaging sensor.
Spatial resolution: The iFOV is inversely related to spatial resolution. A smaller iFOV corresponds to higher spatial resolution because the sensor can distinguish smaller details in the scene.
Calculation: The iFOV can be calculated by considering the sensor's physical dimensions, focal length, and the number of pixels or detectors in the sensor array.
Scanning systems: In scanning systems, the iFOV changes as the sensor or imaging system scans across the scene. The term is used to describe the field of view at any specific instant during the scanning process.
Applications: Understanding iFOV is crucial in various applications, including satellite imagery, aerial photography, thermal imaging, and other remote sensing technologies. It helps determine the level of detail that can be captured by the sensor.
Field of regard: The instantaneous field of view is related to the broader concept of the field of regard, which represents the total angular coverage that an imaging system can achieve.
Understanding iFOV is essential in designing and analyzing imaging systems, as it directly influences the spatial and angular resolution capabilities of the system. High-resolution imaging systems often have smaller iFOVs, allowing them to capture fine details in the observed scene. Conversely, wide-area surveillance systems may have larger iFOVs to cover broader areas at the expense of finer spatial details.