Understanding target-selection modes

In the SAR Polarimetry Target Analysis window, the following target-selection modes are available:

Pixel plus clutter estimation region: You can select a single target pixel at the cursor position and four clutter-estimation regions at the corners of an overall square region that is centered on, but the target pixel and the sidelobe pixels are excluded.
Square neighborhood: You can select a target that includes all pixels within a square region that is centered on the cursor position.
Arbitrary region: You can select either a rectangular or a polygonal target that includes all pixels within the target.

The default target-selection mode is Arbitrary region.

The selected mode determines the target type and, therefore, the polarimetric parameters that can be computed. For example, with Pixel plus clutter estimation region selected, a point target is determined (you are analyzing the response of the center pixel in relation to the clutter pixels). With Square neighborhood or Arbitrary region selected, surface targets are delineated.

Depending on the type of target, several polarimetric parameters are available. For example, the symmetric scattering parameters are applicable only to point targets, whereas parameters applicable to surface targets or that require an averaging of the data (such as entropy) are only enabled when surface targets (Square neighborhood or Arbitrary region) are enabled.

The polarimetric parameters that can be computed also depend on the data set. Polarimetric parameters that require multilook will be unavailable with a single-look complex image, and similarly, the ones that require a fully polarimetric data set (such as polarimetric decompositions) are unavailable with single or dual polarimetric data.

Note: When you change a target-selection mode, under Numerical Output, any check boxes selected previously are cleared.