In supervised classification, we assess how well two classes are separated in feature space. Divergence (and its variants such as Transformed Divergence or Bhattacharyya distance) quantify the statistical separability between class pairs using class mean vectors and covariance matrices. A larger divergence indicates better separability and lower expected classification error.
(A) PCA/Decorrelation stretch is for band decorrelation, not divergence.
(B) Smoothing is a post‐classification spatial filtering step.
(C) Mixed vs homogeneous pixels are not determined by divergence directly.
Thus, divergence analysis is for evaluating separability among class pairs.
\[
\boxed{\text{(D)}}
\]