Digital Picture Processing and Psychophysics: A Study of Brightness Perception,
Abstract
A computer driven display system was used to study brightness contrast phenomena. The modeling approach was that of Stockham and Davidson: the visual system is modeled as the cascade of a linear system (eye optics) and a multiplicative homomorphic system--, i.e., a logarithmic transformation (retinal receptors) followed by a linear system (neural interaction). To test the linearity of neural interaction, smooth stimulus patterns were used. These contained only a few sinusoidal components within the low frequency band and exhibited classical brightness contrast effects (Mach bands, simultaneous brightness contrast, Hermann grid effect). Data, collected from brightness matching experiments with these smooth patterns, were verified in preliminary experiments on similar patterns digitally processed by the inverse of the model, in order to obtain cancellation of the brightness contrast effects. The experimental results were in agreement with Davidson's data, obtained by a fundamentally different method. This experimental approach indicated that the hypothesis of linearity of neural interaction is justified for smooth patterns; further studies suggest that intensity edges and contours cause strong departure from linearity.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1973
- Accession Number
- ADA039006
Entities
People
- Patrick Colas-baudelaire
Organizations
- University of Utah