Addition of a channel mechanism to the ideal-observer model

TLDR

Human observers detect objects in correlated noise with roughly constant efficiency relative to a nonprewhitening ideal observer. The study aims to incorporate a frequency‑selective channel mechanism into the ideal‑observer model. The model adds a frequency‑selective channel mechanism analogous to experimentally validated channel mechanisms for grating detection. Both the nonprewhitening and channelized ideal‑observer models predict similar performance across detection and discrimination tasks, making it hard to distinguish which is more accurate.

Abstract

Several authors have measured the detection ability of human observers for objects in correlated (nonwhite) noise. These studies have shown that the human observer has approximately constant efficiency when compared with a nonprewhitening ideal observer. In this paper we add a frequency-selective mechanism to the ideal-observer model, similar to the channel mechanism that has been demonstrated through experiments that measure a subject’s ability to detect grating stimuli. For a number of detection and discrimination tasks, the nonprewhitening ideal-observer model and the channelized ideal-observer model yield similar performance predictions. Thus both models seem equally capable of explaining a considerable body of psychophysical data, and it would be difficult to devise an experiment to determine which model is more nearly correct.