Symmetric extension for Quincunx filter banks

Symmetric extension is a commonly used technique for constructing nonexpansive transforms for one-dimensional signals of finite length. In this paper, we show how to extend this technique to the two-dimensional case with perfect reconstruction Quincunx filter banks composed of quadrantally-symmetric linear-phase filters. We derive the constraints on the group delays and symmetry types of the analysis filters, in particular those with non-integer vector group delays.