Why compare ICA to PCA? One reason is that the literature on the subject is contradictory.
Bartlett, et al. [4,6], Liu and Wechsler [30], and Yuen and Lai [41] claim
that ICA outperforms PCA for face recognition, while Baek et al. [1] claim that PCA
outperforms ICA and Moghaddam [32] claims that there is no statistical difference in
performance between the two. In a recent study with visible light and infra-red images,
Socolinsky and Salinger report that ICA outperforms PCA on visible light images,
but PCA outperforms ICA on LWIR images [37]. We also know of cases where
researchers informally compared ICA to PCA while building a face recognition system,
only to select PCA. The relative performance of the two techniques is therefore,
an open question.