5.6 Incidence Angle

Incidence Angle

Incidence angle describes the relationship between radar illumination and the ground surface. Specifically, it is the angle between the radar beam and a target object. The incidence angle helps to determine the appearance of a target on an image.

Local Incidence Angle

A local incidence angle can be determined for any pixel on an image. Trees, rocks, buildings, other structures and different terrains create changes in the local incidence angle. This in turn causes variations in pixel brightness.

Local incidence angle influence on pixel brightness

Due to their greater altitude, satellite incidence angles vary less than airborne incidence angles. This leads to more uniform illumination on satellite images than airborne radar images.

Incidence angle variation from aircraft versus satellites