Visual Perception

Visual Perception explores fundamental topics underlying the field of visual perception, including the perception of brightness and color, the physics of light, and the optics of the eye. Although the text leans heavily on physical and physiological concepts, explanations of the relevant physics and physiology are considered. This book is organized into 16 chapters and begins with an overview of the relationship between information assimilation and the physiology of the visual system based on data gathered both in physiological and perceptual experiments. More specifically, this text discusses the nature of the human perceptual system in terms of the kinds of information that are assimilated from the world, and how this selection of information is governed by the structure of receptors and the neural circuits that are connected to them. The relationships between symbols and their corresponding physical and physiological variables are also examined. Finally, the book addresses the presence of strong lateral inhibition in the visual system and how it fits the concept of evolution. This book is aimed at undergraduate and graduate students, regardless of their academic backgrounds.

Preface

I. Introduction

Information

II. The Experiment of Hecht, Schlaer, and Pirenne

The General Design of the Experiment

The State of the Subject — Dark Adaptation

Location of the Test Flash in the Visual Field

Size of the Test Flash — Spatial Summation

Duration of the Test Flash — Temporal Summation

Color of the Test Flash — The Spectral Sensitivity Curve

The Experiment Itself

The Interpretation of Results

Problems

III. The Physics of Light

A Definition of "Seeing"

Light Sources

Lenses and Refraction

The Intensity of an Image

Depth of Focus

The Stimulus in the Hecht Experiment

Collimated Light

Sources of Imperfection of the Retinal Image

Measurements of the Real Retinal Image

Problems

IV. Quantal Fluctuations

Quantal Fluctuations in the Stimulus

The Relationship between Quantal Fluctuation and the Subject's Variability

Sources of Subject Variability

Quantal Fluctuations at Suprathreshold Light Levels

Problems

V. The Action of Light on Rod Pigments

Changes in Rhodopsin Molecules in the Light and in Darkness

The Characteristics and Perceptual Correlates of State a

The Characteristics and Perceptual Correlates of States b, c, and d

Problem

VI. The Excitation of Rods

The Fundamentals of Neural Activity

The Excitation of Retinal Structures as a Consequence of the Absorption of Quanta

Dark Adaptation and Rod Excitation

The Early Stage of Dark Adaptation

VII. Cones and Cone Pigment

Histological Properties of Rods and Cones

Psychophysical Distinctions between Rods and Cones

Individual Differences

The Nature of Cone Pigments

The Kinetics of Cone Pigments

Problem

VIII. Color Vision I - Discriminations among Wavelength Mixtures

Color Names

Monochromacy

Dichromacy

Trichromacy

Color Blindness

Wavelength Mixture Space

Color Reproduction for the Dichromat

The Color Mixture Space of the Trichromat

A Cure for Color-Blindness

Problems

IX. Color Vision II - Retinal Color Systems

Possible Trichromatic Mechanisms

Measurements of the Mechanisms of Human Color Systems

Microspectrophotometry of the Human Retina

Classes of Cones in the Retina

Tetrachromacy

Evaluation of the Assumption That All Absorbed Quanta Produce Identical Effects

The Stability of Wavelength Mixture Matches

Problem

X. Color Vision III - The Perception of Color

The Relationship between Perceived Color and the Physical Stimulus

Differences between Hue, Saturation, and Brightness

Factors other Than Wavelength That Influence Hue

Stimulus Generalization

The Physiological Correlates of Perceived Colors

Logarithmic Transformations and Approximations to Them

Application of a Nonlinear Transformation to the Perception of Hue

Physiological Measures of Wavelength-Dependent Responses

XI. The Psychophysiology of Brightness - I Spatial Interaction in the Visual System

Demonstrations that Brightness Is Not a Simple Function of Intensity

Evidence Concerning the Physiological Nature of Spatial Interaction in the Visual System

Lateral Inhibition in the Retinas of Mammals

XII. Psychophysiology of Brightness - II Modulation Transfer Functions

Modulation Transfer Functions

Conditions Necessary for Correct Use of the MTF

Human Visual Modulation Transfer Functions

Perceptual Phenomena Related to the Transfer Function

Physiological Implications of the Modulation Transfer Function

XIII. Brightness and Color Constancy

Is All This Perception?

A Physiological Explanation of Brightness Constancy

The Limits of Brightness Constancy

Hue Contrast and Hue Constancy

XIV. Temporal Properties of the Visual Systems

Phase

The Temporal Modulation Transfer Function

Physiological Correlates of Temporal Events

XV. Stimulus Generalization

The Generalization of Visual Shapes

Physiological Evidence for Mammalian Generalization Mechanisms

XVI: Speculations on "Higher Processes"

Why Did Inhibition Evolve?

"Higher" Processes

Appendix I Visual Angle

Appendix II Filter Transmission Versus Density

Appendix III How to Build an Ophthalmoscope

Theory of Operation

Specific Construction Details

Appendix IV Demonstration of Color Contrast (Colored Shadows)

References

Suggested General Readings

Author Index

Subject Index