It can be difficult to recognize someone from a photo of their face if it’s turned upside-down, or presented as a negative. But what if the photos are distorted – fairground-mirror style? Or deliberately blurred?
To find out, Dr Graham Hole and colleagues at the School of Cognitive and Computing Sciences, University of Sussex, UK, performed a set of experiments.
Finding (amongst other things) that :
Global linear transformations seem to affect recognition remarkably little, considering the extent to which they distort the spatial relationships within a face, which are presumed to be critical for recognition. Recognition was impaired, however, when vertical stretching was applied nonglobally (ie to only half of the face).
See: Effects of Geometric Distortions on Face-Recognition Performance, Volume: 31, issue: 10, pages 1221-1240. (A full copy of which may be found here)