Three Stages and Two Systems of Visual Processing
Abstract
Three stages of visual processing determine how internal noise appears to an external observer: light adaptation, contrast gain control, and a postsensory/decision stage. Dark noise occurs prior to adaptation, determines dark-adapted absolute thresholds, and mimics stationary external noise. Sensory noise occurs after dark adaptation, determines contrast thresholds for sine gratings and similar stimuli, and mimics external noise that increases with mean luminance. Postsensory noise incorporates perceptual, decision, and mnemonic process. It occurs after contrast-gain control and mimics external noise that increases with stimulus contrast (i.e., multiplicative noise). Dark noise and sensory noise are frequently specific and primarily affect weak signals. Only postsensory noise significantly affects to strong signals, and it has constant power over a wide spatial frequency range in which sensory noise varies enormously. Optics, Reprints.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1989
- Accession Number
- ADA212670
Entities
People
- George Sperling
Organizations
- New York University