Let's read! We will often find out this sentence everywhere. When still being a kid, mom used to order us to always read, so did the teacher. Some books are fully read in a week and we need the obligation to support reading. What about now? Do you still love reading? Is reading only for you who have obligation? Absolutely not! We here offer you a new book enPDFd the perception of the visual world to read.

The Perception of the Visual World. By James J. Gibson. U.S.A.: Houghton Mifflin Company, 1950 (George Allen & Unwin, Ltd., London). Price 35s.

Descriptions of physical properties of visible surfaces, such as their distance and the presence of edges, must be recovered from the primary image data. Computational vision aims to understand how such descriptions can be obtained from inherently ambiguous and noisy data. A recent development in this field sees early vision as a set of ill-posed problems, which can be solved by the use of regularization methods. These lead to algorithms and parallel analog circuits that can solve ‘ill-posed problems’ and which are suggestive of neural equivalents in the brain.

Computational vision and regularization theory

The computational view of mind rests on certain intuitions regarding the fundamental similarity between computation and cognition. We examine some of these intuitions and suggest that they derive from the fact that computers and human organisms are both physical systems whose behavior is correctly described as being governed by rules acting on symbolic representations. Some of the implications of this view are discussed. It is suggested that a fundamental hypothesis of this approach (the “proprietary vocabulary hypothesis”) is that there is a natural domain of human functioning (roughly what we intuitively associate with perceiving, reasoning, and acting) that can be addressed exclusively in terms of a formal symbolic or algorithmic vocabulary or level of analysis.Much of the paper elaborates various conditions that need to be met if a literal view of mental activity as computation is to serve as the basis for explanatory theories. The coherence of such a view depends on there being a principled distinction between functions whose explanation requires that we posit internal representations and those that we can appropriately describe as merely instantiating causal physical or biological laws. In this paper the distinction is empirically grounded in a methodological criterion called the “cognitive impenetrability condition.” Functions are said to be cognitively impenetrable if they cannot be influenced by such purely cognitive factors as goals, beliefs, inferences, tacit knowledge, and so on. Such a criterion makes it possible to empirically separate the fixed capacities of mind (called its “functional architecture”) from the particular representations and algorithms used on specific occasions. In order for computational theories to avoid being ad hoc, they must deal effectively with the “degrees of freedom” problem by constraining the extent to which they can be arbitrarily adjusted post hoc to fit some particular set of observations. This in turn requires that the fixed architectural function and the algorithms be independently validated. It is argued that the architectural assumptions implicit in many contemporary models run afoul of the cognitive impenetrability condition, since the required fixed functions are demonstrably sensitive to tacit knowledge and goals. The paper concludes with some tactical suggestions for the development of computational cognitive theories.

Computation and cognition: Issues in the foundations of cognitive science.

Publisher Summary
This chapter discusses three questions: Why are there so many sources of information about layout? How is it that one perceives layout with near-metric accuracy when none of these sources yields metric information about it? Can one not do better, theoretically, in understanding the perception of layout than simply make a list? The answer to the first question begins with Todd's answer. Perceiving layout is extremely important to human beings, so important that it must be redundantly specified so that the redundancy can guard against the failure of any given source or the failure of any of the assumptions on which a given source is based. However, information redundancy is only part of the answer. Different sources of information about layout metrically reinforce and contrast with each other, providing a powerful network of constraints. The answer to the second proceeds from this idea. Through the analysis of depth-threshold functions for nine different sources of information about layout, one can begin to understand how those sources of information sharing the same-shaped functions across distances can help ramify judgments of layout by serving to correct measurement errors in each. Third, on the basis of the analyses and the pattern of functions, it suggests that list making has misled about space and layout. Psychologists and other vision scientists have generally considered layout, space, and distance as a uniform commodity in which observers carry out their day-to-day activities.

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Perceiving Layout and Knowing Distances: The Integration, Relative Potency, and Contextual Use of Different Information about Depth*

The problem of how three-dimensional form is perceived in spite of the fact that pertinent stimulation consists only in two-dimensional retinal images has been only partly solved. Much is known about the impressive effectiveness of binocular disparity. However, the excellent perception of threedimensional form in monocular vision has remained essentially unexplained. It has been proposed that some patterns of stimulation on the retina give rise to three-dimensional experiences, because visual processes differ in the spontaneous organization that results from certain properties of the retinal pattern. Rules of organization are supposed to exist according to which most retinal projections of three-dimensional forms happen to produce three-dimensional percepts and most retinal images of flat forms lead to flat forms in experience also. This view has been held mainly by gestalt psychologists. Another approach to this problem maintains that the projected stimulus patterns are interpreted on the basis of previous experience, either visual

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The kinetic depth effect.

The kinetic depth effect that has been discussed in a preceding paper (2) enables monocular Ss to perceive three-dimensional form as directly as do persons with serviceable binocular vision by means of retinal disparity. Yet this effect alone does not, of course, solve the entire problem of the perception of solid form. Threedimensional form is seen monocularly also when the observer does not move in relation to the object and it is also perceived in photographs and drawings. It has been mentioned in the preceding paper that an empiristic explanation of these cases of threedimensional form perception becomes more feasible through the demonstration of the kinetic depth effect. This is so because no empiristic explanation can be termed successful until it is made clear how the original process •or experience is brought about under whose influence current experience is supposed to occur. Prior to the demonstration of the kinetic depth effect (KDE) no process was known which could account in a satisfactory way for the \"original\" perception of threedimensional form in monocular Ss. Two different approaches have been made to explain the perception of three-dimensional form that occurs in the absence of retinal disparity or of other specific cues for visual depth. It has been proposed that threedimensional forms are seen under these circumstances because the corresponding retinal patterns have the power to evoke them directly. Gibson (1), who holds such a view, believes that such retinal patterns have geometric characteristics which are specific stimuli for depth just as there are specific stimuli for color, pitch, etc. A'lany Gestalt psychologists believe that visual processes are spontaneously organized so that certain patterns of stimulation lead to three-dimensional forms and others to plane forms in perception and they have tried to formulate the principles which underlie such organization. When three-dimensional objects are seen as threedimensional forms, it is due to the fact that their retinal projections have properties which favor organization as three-dimensional forms. The other approach is, of course, the empiristic one. It is believed that previous experiences can cause a present perception in three dimensions. For a number of reasons, one of which—the nature of the KDE itself— will be discussed below, we came to believe that an influence of past experience plays an important role in the perception of three-dimensional form and set out to demonstrate such an effect in a stringent way. Such a demonstration requires that a retinal pattern, which at the outset is seen as a plane figure, gives rise under identical external conditions to the perception of a three-dimensional form after an intervening exposure of the same pattern given under conditions which cause it to be seen as three-dimensional.

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D. N. O'Connell

Papers

The kinetic depth effect.

The memory effect of visual perception of three-dimensional form.