Analysis of the Relationship between the Incident Angle and Polarimetric Signatures with POLSAR Data

This paper studies the effect of the variation of incident angle on polarimetric signatures for different kinds of terrain. The signatures include span, polarimetric entropy (H), anisotropy (A), Alpha angle and three components of Freeman decomposition. After analyzing polarimetric signatures of airborne POLSAR data, we find that when incident angle is smaller than around 55°, the signatures of different kinds of terrain are easy to be distinguished between each other. But if the incident angle is still increasing, then the signatures of different terrains are difficult to be discriminated, especially for the H/A/α parameters. We also find that the H/A parameters are having an increasing trend when the incident angle increases, while the other parameters are showing a decreasing trend.