“…S UBSPACE learning for computer vision applications has recently attracted a lot of interest in the scientific community [1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14], [15]. This research has been primarily motivated by the development of a multitude of techniques for the efficient analysis of high-dimensional data via non-linear dimensionality reduction [3], [4], [5], [6], [10], [13].…”