What is DFOV and HFOV and VFOV?

FOV is the field of view, and a lens contains 3 angles: DFOV is the diagonal angle, HFOV is the horizontal angle, and VFOV is the vertical angle. DFOV, HFOV, and VFOV are terms commonly used in the field of optics and imaging. They refer to different types of fields of view that a camera or imaging system can capture.
DFOV or diagonal field of view is the widest angle of view captured by a camera or imaging system. It measures the diagonal distance of the imaging area and is the most commonly used field of view measurement.
HFOV or horizontal field of view describes the maximum width of an image or video frame that can be viewed horizontally. This measurement is often used in surveillance cameras, where the width of the frame is critical to ensure complete coverage of the area.
VFOV or vertical field of view describes the highest angle of view captured by a camera or imaging system. This measurement is often used in applications such as aerial photography or drone imaging.