The Visual Perception Of Spatial Extent

This study was concerned with the manner in which perceived depth and perceived frontoparallel size varied with physical distance and hence with each other. An equation expressing the relation between perceived frontoparallel size and physical depth was developed and applied to frontoparallel size judgments determined with four observers under two viewing conditions. Using the same equation and an expression of the size-distance invariance hypothesis, an additional equation was developed which related perceived and physical depth. The additional equation, when applied to judgments of perceived depth from the same observers under the same viewing conditions, produced results not in agreement with those expected from the sizedistance invariance hypothesis. This is interpreted as evidence against the validity of the size-distance invariance hypothesis in its usual form. The results from the apparent depth judgments also were applied to the problem of the nonveridicality of the perceptual bisection of depth intervals. (Author).

Psychophysical Analysis of Visual Space focuses on the use of psychophysics in the analysis of visual space, with emphasis on space perception and physiological optics. Topics covered include null-size judgment, ratio-size judgment, frontal-size judgment, and distance judgment, as well as selected physiological correlates of size and distance judgments. A theoretical analysis of model reduction is also presented. This volume consists of 11 chapters and opens with an overview of basic definitions and evidence in support of the constancy hypothesis. A psychophysical approach to the problems of visual space is described. The reader is then introduced to null-size judgment, ratio-size judgment, frontal-size judgment, and distance judgment, with emphasis on the importance of the retina as a reference for spatial judgments and how size judgments of targets at different distances can be related to judgments of targets at a constant distance. Some of the important relationships between ocular physiology and size-distance judgments are also examined, paying particular attention to size and distance judgments which relate to the variables of convergence, accommodation, angle-of-regard, and binocular disparity. The remaining chapters look at two stimulus correlates of distance judgments: frontal size and longitudinal size. This book will be of interest to physiologists, physicists, and experimental psychologists.

Sometime between 1028 and 1038, Ibn al-Haytham completed his monumental optical synthesis, Kitab al-Manazir ("Book of Optics"). By no later than 1200, and perhaps somewhat earlier, this treatise appeared in Latin under the title De aspectibus. In that form it was attributed to a certain "Alhacen." These differences in title and authorial designation are indicative of the profound differences between the two versions, Arabic and Latin, of the treatise. In many ways, in fact, they can be regarded not simply as different versions of the same work, but as different works in their own right. Accordingly, the Arab author, Ibn al-Haytham, and his Latin incarnation, Alhacen, represent two distinct, sometimes even conflicting, interpretive voices. And the same holds for their respective texts. To complicate matters, "Alhacen" does not represent a single interpretive voice. There were at least two translators at work on the Latin text, one of them adhering faithfully to the Arabic original, the other content with distilling, even paraphrasing, the Arabic original. Consequently, the Latin text presents not one, but at least two faces to the reader. This two-volume critical edition represents fourteen years of work on Dr. Smith's part. Awarded the 2001 J. F. Lewis Award.

When most people think of space, they think of physical space. However, visual space concerns space as consciously experienced, and it is studied through subjective measures, such as asking people to use numbers to estimate perceived distances, areas, angles, or volumes. This book explores the mismatch between perception and physical reality, and describes the many factors that influence the perception of space including the meaning assigned to geometric concepts like distance, the judgment methods used to report the experience, the presence or absence of cues to depth, and the orientation of a stimulus with respect to point of view. The main theme of the text is that no single geometry describes visual space, but that the geometry of visual space depends upon the stimulus conditions and mental shifts in the subjective meaning of size and distance. In addition, The Geometries of Visual Space: *contains philosophical, mathematical, and psychophysical background material; *looks at synthetic approaches to space perception including work on hyperbolic, spherical, and Euclidean geometries; *presents a meta-analysis of studies that ask observers to directly estimate size, distance, area, angle, and volume; *looks at the size constancy literature in which observers are asked to adjust a comparison stimulus to match a variety of standards at different distances away; *discusses research that takes a multi-dimensional approach toward studying visual space; and *discusses how spatial experience is influenced by memory. While this book is primarily intended for scholars in perception, mathematical psychology, and psychophysics, it will also be accessible to a wider audience since it is written at a readable level. It will make a good graduate-level textbook on space perception.

Perspectives in Computing: Human and Machine Vision II compiles papers presented at the second Workshop on Human and Machine Vision held in Montreal, Canada on August 1-3, 1984. This book discusses the perception of transparency in man and machine, human image understanding, and connectionist models and parallelism in high level vision. The theory of the perceived spatial layout of scenes, generative systems of analyzers, and codon constraints on closed 2D shapes are also elaborated. This text likewise covers the environment- and viewer-centered perception of surface orientation, autonomous scene description with range imagery, and pre-attentive processing in vision. This publication is recommended for students and researchers interested in both fields of visual perception and computer vision.