Image processing analysis of traditional Gestalt vision experiments (original) (raw)
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Image processing analysis of traditional Gestalt vision experiments
9th Congress of the International Colour Association, 2002
In the late 19th century, the Gestalt Psychology rebelled against the popular new science of Psychophysics. The Gestalt revolution used many fascinating visual examples to illustrate that the whole is greater than the sum of all the parts. Color constancy was an important example. The physical interpretation of sensations and their quantification by JNDs and Weber fractions were met with innumerable examples in which two "identical" physical stimuli did not look the same. The fact that large changes in the color of the illumination failed to change color appearance in real scenes demanded something more than quantifying the psychophysical response of a single pixel. The debate continues today with proponents of both physical, pixel-based colorimetry and perceptual, image-based cognitive interpretations. Modern instrumentation has made colorimetric pixel measurement universal. As well, new examples of unconscious inference continue to be reported in the literature. 1 Image processing provides a new way of analyzing familiar Gestalt displays. Since the pioneering experiments by Fergus Campbell 2 and Land 3 , we know that human vision has independent spatial and color channels. Color matching data from color constancy experiments agrees with spatial comparison analysis. 4 In this analysis, simple spatial processes can explain the different appearances of "identical" stimuli by analyzing the multiresolution spatial properties of their surrounds. Benary's Cross 5 , White's Effect 5 , the Checkerboard Illusion 6 and the Dungeon Illusion can all be understood by the analysis of their low-spatial-frequency components. Just as with color constancy, these Gestalt images are most simply described by the analysis of spatial components. Simple spatial mechanisms account for the appearance of "identical" stimuli in complex scenes. It does not require complex, cognitive processes to calculate appearances in familiar Gestalt experiments.
A century of Gestalt psychology in visual perception: II. Conceptual and theoretical foundations
Psychological Bulletin, 2012
Our first review article (Wagemans et al., 2012) on the occasion of the centennial anniversary of Gestalt psychology focused on perceptual grouping and figure-ground organization. It concluded that further progress requires a reconsideration of the conceptual and theoretical foundations of the Gestalt approach, which is provided here. In particular, we review contemporary formulations of holism within an information-processing framework, allowing for operational definitions (e.g., integral dimensions, emergent features, configural superiority, global precedence, primacy of holistic/configural properties) and a refined understanding of its psychological implications (e.g., at the level of attention, perception, and decision). We also review 4 lines of theoretical progress regarding the law of Prägnanz-the brain's tendency of being attracted towards states corresponding to the simplest possible organization, given the available stimulation. The first considers the brain as a complex adaptive system and explains how self-organization solves the conundrum of trading between robustness and flexibility of perceptual states. The second specifies the economy principle in terms of optimization of neural resources, showing that elementary sensors working independently to minimize uncertainty can respond optimally at the system level. The third considers how Gestalt percepts (e.g., groups, objects) are optimal given the available stimulation, with optimality specified in Bayesian terms. Fourth, structural information theory explains how a Gestaltist visual system that focuses on internal coding efficiency yields external veridicality as a side effect. To answer the fundamental question of why things look as they do, a further synthesis of these complementary perspectives is required.
Principles of perceptual organization and spatial distortion: The gestalt illusions
Journal of Experimental Psychology: Human Perception and Performance, 1980
In five interleaved experiments, conducted with 94 observers, it is shown that organization of the visual field according to gestalt principles results in measurable spatial distortions. Using the principles of proximity, similarity, good continuation, and two types of closure, it was found that interior distances (within a perceptual unit or group) are underestimated relative to exterior distances. The relationship between these spatial distortions and the resultant perceptual organization are discussed. Requests for reprints should be sent to Stanley Coren,
Gestalt Isomorphism and the Quantification of Spatial Perception
2004
Scientific theory is necessarily founded on certain philosophical assumptions. The philosophical underpinnings of science are not always apparent in mature sciences, where the correct philosophical groundwork has been established with such certainty that alternative philosophies appear too absurd for serious consideration. However in the case of sciences in an embryonic state of development, errors in the philosophical foundations can lead to grave errors in the science built on them. Nowhere is this more true today than in the science of mind and brain. Theories of visual perception can be separated into two classes, depending on their relation to a most significant philosophical distinction, i.e. the distinction between epistemological monism, or naive realism, versus epistemological dualism, or the two-worlds hypothesis. Therefore debates over the relative merits of opposing theories of vis ion are often at cross-purposes whenever the competing theories are founded on different p...
On the structures of perceptual Gestalten
1985
The objects we perceive exhibit structures and properties which are not indigenous to the world as it is in itself. Thus whilst the two horizontal lines in the MiilIer-Lyer illusion are objectively of equal length, they are experienced as being such that one is shorter than the other. There is a distinction between the structure as we experience it, the perceived Gestalt, and the underlying autonomous objectual formation.
2012
1. In 1912, Max Wertheimer published his paper on phi motion, widely recognized as the start of Gestalt psychology. Because of its continued relevance in modern psychology, this centennial anniversary is an excellent opportunity to take stock of what Gestalt psychology has offered and how it has changed since its inception. We first introduce the key findings and ideas in the Berlin school of Gestalt psychology, and then briefly sketch its development, rise, and fall. Next, we discuss its empirical and conceptual problems, and ...
Gestalt isomorphism and the primacy of the subjective perceptual experience
Behavioral and Brain Sciences, 1998
A serious crisis is identified in theories of neurocomputation, marked by a persistent disparity between the phenomenological or experiential account of visual perception and the neurophysiological level of description of the visual system. In particular, conventional concepts of neural processing offer no explanation for the holistic global aspects of perception identified by Gestalt theory. The problem is paradigmatic and can be traced to contemporary concepts of the functional role of the neural cell, known as the Neuron Doctrine. In the absence of an alternative neurophysiologically plausible model, I propose a perceptual modeling approach, to model the percept as experienced subjectively, rather than modeling the objective neurophysiological state of the visual system that supposedly subserves that experience. A Gestalt Bubble model is presented to demonstrate how the elusive Gestalt principles of emergence, reification, and invariance can be expressed in a quantitative model of the subjective experience of visual consciousness. That model in turn reveals a unique computational strategy underlying visual processing, which is unlike any algorithm devised by man, and certainly unlike the atomistic feed-forward model of neurocomputation offered by the Neuron Doctrine paradigm. The perceptual modeling approach reveals the primary function of perception as that of generating a fully spatial virtual-reality replica of the external world in an internal representation. The common objections to this "picture-in-the-head" concept of perceptual representation are shown to be ill founded.
Perceptual organization and neural computation
Journal of Vision
Our present understanding of perceptual organization has its roots in the observations and qualitative principles of the Gestalt psychologists. Gestaltists and their associates identified and classified phenomena that reflect how perceptual systems derive representations of the environment based on fragmentary information and stimulus context. A broad range of phenomena was explored in this early work. The perceptual organization of visual motion was a major focus, involving both simple (Korte, 1915; Ternus, 1936; von Schiller, 1933; Wertheimer, 1912) and complex (Duncker, 1929; Musatti, 1924; Rubin, 1927; Wallach, 1935) motion patterns. The perceptual organization of static form was explored in studies of part–whole relationships in simple planar figures (Rubin, 1915; Wertheimer, 1923/1938) and later in studies of illusory contours and amodal completion (Kanizsa, 1955; Michotte, Thinès, & Crabbé, 1964). Additional topics included lightness and color phenomena (Benary, 1924; Gelb, 1929; Katz, 1935; Wallach, 1948) and the perception of events (Michotte, 1941). In brief, the research areas addressed by the first generations of Gestalt psychologists spanned much of what is now vision science. The broad impact of Gestalt ideas is reflected in the exceptional scope of this special issue.