Correction to: Chapter 13 in: R. Jiang et al. (eds.), Biometric Security and Privacy, Signal Processing for Security Technologies, https://doi.org/10.1007/978-3-319-47301-7_13

The book was inadvertently published without clear indication of the provenance of some of the images in the figures of this chapter. This has now been corrected, and the images published without permission were removed.