Target shadow detector for synthetic aperture radar

Targets imaged by radar systems typically have shadows associated with them. Target detection and identification is enhanced by analyzing the shadow characteristics of a suspected target. Features of the shadow cast by the suspected target enhance the identification process. Authenticating the suspected target shadow as being indeed cast by the target comprisesa) Generating a radar image using radar returns, the radar image containing both the target and its suspected target shadow;b) Forming a pentagonal perimeter adjacent to the target (within the radar image), the pentagonal perimeter chosen to contain the suspected target shadow, the pentagonal perimeter separating the target from its suspected target shadow;c) Testing the suspected target shadow within said pentagonal perimeter to authenticate that the suspected target shadow is cast by the target.One aspect of the testing performed on the suspect target shadow uses a 2 by 2 dilation and majority filter. Other tests performed are an adjacent overlap test, an edge pixel count test, a maximum area and minimum distance test as well as an area threshold test.The original radar image is converted to a magnitude only form from its I and Q components and a magnitude thresholding is applied to the radar image to obtain a binary image.