SECTION ONE: GENERAL BACKGROUND SECTION TWO: GROUPS, PATTERNS, TEXTURES SECTION THREE: CONTOURS AND SHAPES SECTION FOUR: FIGURE-GROUND ORGANIZATION SECTION FIVE: SURFACE AND COLOUR PERCEPTION SECTION SIX: MOTION AND EVENT PERCEPTION SECTION SEVEN: PERCEPTUAL ORGANIZATION AND OTHER MODALITIES SECTION EIGHT: SPECIAL INTEREST TOPICS SECTION NINE: APPLICATIONS OF PERCEPTUAL ORGANIZATION SECTION TEN: THEORETICAL APPROACHES

The Oxford handbook of perceptual organization

The appearance of an object or surface depends strongly on the light from other objects and surfaces in view. This review focuses on color in complex scenes, which have regions of different colors in view simultaneously and/or successively, as in natural viewing. Two fundamental properties distinguish the chromatic representation evoked by a complex scene from the representation for an isolated patch of light. First, in complex scenes, the color of an object is not fully determined by the light from that object reaching the eye. Second, the chromatic representation of a complex scene contributes not only to hue, saturation, and brightness, but also to other percepts such as shape, texture, and object segmentation. These two properties are cornerstones of this review, which examines color perception with context that varies over space or time, including color constancy, and chromatic contributions to such percepts as orientation, contour, depth, and motion.

Color in Complex Scenes

Contrast as a depth cue

The shape of the contour separating two regions strongly influences judgments of which region is “figure” and which is “ground.” Convexity and other figure–ground cues are generally assumed to indicate only which region is nearer, but nothing about how much the regions are separated in depth. To determine the depth information conveyed by convexity, we examined natural scenes and found that depth steps across surfaces with convex silhouettes are likely to be larger than steps across surfaces with concave silhouettes. In a psychophysical experiment, we found that humans exploit this correlation. For a given binocular disparity, observers perceived more depth when the near surface's silhouette was convex rather than concave. We estimated the depth distributions observers used in making those judgments: they were similar to the natural-scene distributions. Our findings show that convexity should be reclassified as a metric depth cue. They also suggest that the dichotomy between metric and nonmetric depth cues is false and that the depth information provided many cues should be evaluated with respect to natural-scene statistics. Finally, the findings provide an explanation for why figure–ground cues modulate the responses of disparity-sensitive cells in visual cortex.

/pdf/natural-scene-statistics-predict-how-the-figure-ground-cue-2eu7d0y2or.pdf

Natural-Scene Statistics Predict How the Figure–Ground Cue of Convexity Affects Human Depth Perception

Our understanding of human color vision has advanced tremendously in recent years, helped along by many new discoveries, ideas, and achievements. It is therefore timely that these new developments are brought together in a book, assembled specifically to include new research and insight from the leaders in the field. Although intentionally not exhaustive, many aspects of color vision are discussed in this Springer Series in Vision Research book including: the genetics of the photopigments; the anatomy and physiology of photoreceptors, retinal and cortical pathways; color perception; the effects of disorders; theories on neuronal processes and the evolution of human color vision. Several of the chapters describe new, state-of-the-art methods within genetics, morphology, imaging techniques, electrophysiology, psychophysics, and computational neuroscience. The book gives a comprehensive overview of the different disciplines in human color vision in a way that makes it accessible to specialists and non-specialist scientists alike.

Emmanuelle Malbert

Papers

The role of colour as a monocular depth cue