, Volume 58, Issue 4, pp 602-612

Effects of high-pass and low-pass spatial filtering on face identification

Abstract

If face images are degraded by block averaging, there is a nonlinear decline in recognition accuracy as block size increases, suggesting that identification requires a critical minimum range of object spatial frequencies. The identification of faces was measured with equivalent Fourier low-pass filtering and block averaging preserving the same information and with high-pass transformations. In Experiment 1, accuracy declined and response time increased in a significant nonlinear manner in all cases as the spatial-frequency range was reduced. However, it did so at a faster rate for the quantized and high-passed images. A second experiment controlled for the differences in the contrast of the high-pass faces and found a reduced but significant and nonlinear decline in performance as the spatial-frequency range was reduced. These data suggest that face identification is preferentially supported by a band of spatial frequencies of approximately 8-16 cycles per face; contrast or line-based explanations were found to be inadequate. The data are discussed in terms of current models of face identification.

N.P.C. was employed on ESRC/MRC/SERC Joint Council Initiative in Cognitive Science and Human-Computer Interaction Grant 9002054 to I. Craw, H. D. Ellis, and J.W. Shepherd, and SERC Grant GR/J04951 to V. Bruce, A. M. Burton, and I. Craw.