Predicting human performance by a channelized Hotelling observer model

A psychophysical experiment was conducted to measure the performance of human observers in detecting an exactly known signal against a random, nonuniform background in the presence of noise correlations introduced by post-detection filtering (postprocessing). In order to predict this human performance, a new model observer was synthesized by adding frequency-selective channels to the Hotelling observer model which we have previously used for assessment of image quality. This new `channelized' Hotelling model reduces approximately to a nonprewhitening (NPW) observer for images with uniform background and correlated noise introduced by filtering, and to a Hotelling observer for images with nonuniform background and no postprocessing. For images with both background nonuniformity and post processing, the performance of this channelized Hotelling observer agrees well with human performance while the other two observer models (NPW and Hotelling observer) fail.