Spatial frequency range in the detection process--1. Narrow bars.

The effect upon the detectability of narrow bars of ideal low-pass and high-pass filters was investigated. The results indicate that for optimum detection of the stimulus, spatial frequency components up to about 10 c/deg need to be transmitted. Two models (a multi-channel model, incorporating probability summation across spatial frequency, and a Grating Sensitivity Curve model) were used in attempting to fit the results. The multi-channel model provided a more realistic fit, but both models ultimately failed because of non-linearity in the summation of responses to frequency components.