Noisy templates explain area summation

The noisy template model is a variant of an ideal detector for a signal kno wn except for contrast. The ideal detector cross-correlates the stimulus wi th a normalised template which is matched to the known signal pattern. The noisy template model simply adds noise to the matched template every time i t is cross-correlated with the signal. This paper outlines the predictions of the noisy template model for area summation. The noisy template model ex plains Piper's Law, as does the ideal-observer, but it also explains critic al area phenomena and the lack of area summation for contrast discriminatio n. (C) 1998 Elsevier Science Ltd. All rights reserved.