Download or read book Cortical Representation of Illusory and Surface Color written by Andrew J. Coia and published by . This book was released on 2016 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: In order to see the world as we do our visual system constantly performs many amazing feats that are largely unknown to us, the viewers. In order to create and update a seamless and coherent representation of the world, our eyes and brain have to deal with many obstacles that could interfere with object recognition such as occluding blood vessels in our eyes, layers of occluding retinal neurons, the blind spot that is devoid of photoreceptors, objects and shadows occluding other objects, and retinal inhomogeneities. Ultimately, we obtain information that encodes relative brightness and colors that allow us to recognize different objects and surfaces. How is it that we obtain the information to assign color to object surfaces? It has been hypothesized that we predominantly extract information about the color of an object from the spectral contrast at the edges and fill in the remaining areas (if the edge information is consistent with that from a uniform surface). These ideas have been put forth to explain striking visual illusions such as the Cornsweet Illusion, neon color spreading, and the watercolor effect. All of these illusions exist in both color and brightness domains. Thus, even though it may not be intuitively obvious, edges play a key role in our final percept of what color we see when viewing an object. It is said that we 'perceptually fill in' color from edges similarly to how our visual system fills in the blind spot in our eye. Of course it should be noted that spectral information may also be available from within the regions away from the edges and this information may also play an important role in the perception of surface color. The theory that edge information alone determines color and that internal surface information is discarded implies that there is no difference in neural computation of physical surface color and edge induced color spreading. Initial studies of this question suggest that illusory colors and actual surface colors may in fact show important differences. One goal of the present study is to employ both psychophysics and electrophysiology to determine under what conditions illusory colors and surface colors are differentiated to provide insights into the fundamental processes involved in surface color perception. If filling-in is indeed important for surface color perception, then how might color filling-in occur? One possibility is that information from the edges might be propagated in a feedforward manner that passively spreads until another edge or contradicting information is encountered. Another possibility is that edge information could be relayed to higher order form centers and then surface colors reconstructed from feedback from those higher regions. The question of feed-forward vs. feedback mechanisms of perception has been debated by scientists since at least the time of Hering and Helmholtz, Hering favoring a bottom up interpretation while Helmholtz argued that our visual system performs 'unconscious inferences.' It is currently appreciated that a relatively sparse sampling of visual information from the world results in a rich visual percept, supporting the idea that much of our vision is actually reconstructed from past experience. Another goal of the present study is to apply electrophysiological methods (hdEEG) to determine the relative importance of feed-forward and feedback mechanisms in surface color perception. This work expands on previous research which developed a method of measuring the watercolor illusion with single channel VEP. This dissertation provides a literature review of the background and significance of the problems, presents preliminary data, outlines the series of proposed experiments, and lastly the results of the proposed experiments.
Download or read book Illusory Contour and Surface Completion Mechanisms in Human Visual Cortex written by Mark Anthony Halko and published by . This book was released on 2008 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: The human visual system processes images projected to the retina and transforms this information into representations of objects in the real world. A fundamental stage in the transformation is extraction of visual contours and surfaces. In part, contour identification is performed by neurons sensitive to luminance edges (Hubel & Wiesel, 1962); however, contours and surfaces can also be perceived in instances without explicit luminance edges (Kanizsa, 1955; Schumann, 1900). These phenomena, known as illusory contours, drive visual cortical responses (Mendola et al., 1999; von der Heydt et al., 1984) and offer an important window into the mechanisms of contour and surface perception. First, a novel display, the Chomping Pacman (CP) illusion, is described. Illusory contour clarity is enhanced relative to traditional illusory contour figures. The CP illusion is combined with a method of adjustment technique to dissect contributions of three mechanisms of contour completion: extrapolation, interpolation, and figural processes. When occlusion cues are present, one or more mechanisms are blocked, yet modal (or visible) contours are still observed to persist. These studies question contour theories based solely on local cues without figural mechanisms. Second, functional MRI (fMRI) was employed to image human brain activity when subjects viewed the CP illusion. Activity in lateral occipital (LO) cortex was observed when contours were formed with or without the percept of a complete figure, indicating LO is a site of both contour and figure completion, contrary to previous reports of figure completion only in LO (Stanley & Rubin, 2003). Figure activity was found in all midlevel visual regions, intraparietal sulcus (IPS), LO, MT and V4, suggesting figure-based mechanisms of completion involve areas in addition to LO. Finally, fMRI was utilized to investigate changes in brain activity that occur with increases in the perceptual vividness of an illusory contour figure. Perceptual vividness was enhanced via coherent motion cues and via neon color spreading (NCS) in the Chomping Pacman display. A brain area encoding perceptual vividness should give greater activation for illusory figures than for non-figures, for motion illusory figures than for static illusory figures, and for NCS illusory figures than for achromatic illusory figures. Five visual cortical areas met these criteria, areas: V3B, hV4, LOCvt, IPS2, and IPS3. These results demonstrate that perceptual vividness of illusory contour figures is reflected in the activity in both the dorsal and ventral visual streams for both color and motion percepts.
Download or read book The Perception of Illusory Contours written by Susan Petry and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 802 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Perception of Illusory Contours is a complete and comprehensive volume on one of the most important phenomena in modern perception research. An illusory contour is a demonstration in which people perceive edges, surfaces, objects and colors that have no physical reality. The international group of distinguished researchers which comprise the contributors to the volume present new theoretical interpretations and data in addition to reviewing the extensive literature on this topic. The volume begins with an introduction to the research on and theories behind illusory contours and their applications to other areas of perception, cognitive science and art. The collection also features English language translations of the seminal papers by Schumann, Ehrenstein, and Kanizsa, the scientists who originally discovered and investigated the phenomenon. The Perception of Illusory Contours contains the most comprehensive set of illusory contour figures ever assembled. The volume is a most significant reference work in an area of research at the critical intersection of perception, cognitive science, visual neurophysiology, and artificial intelligence.
Download or read book Encyclopedia of Color Science and Technology written by Renzo Shamey and published by Springer Nature. This book was released on 2023-09-29 with total page 1634 pages. Available in PDF, EPUB and Kindle. Book excerpt: This fully revised and expanded 2nd edition provides a single authoritative resource describing the concepts of color and the application of color science across research and industry. Significant changes for the 2nd edition include: New and expanded sections on color engineering More entries on fundamental concepts of color science and color terms Many additional entries on specific materials Further material on optical concepts and human visual perception Additional articles on organisations, tools and systems relevant to color A new set of entries on 3D presentation of color In addition, many of the existing entries have been revised and updated to ensure that the content of the encyclopedia is current and represents the state of the art. The work covers the full gamut of color: the fundamentals of color science; the physics and chemistry; color as it relates to optical phenomena and the human visual system; and colorants and materials. The measurement of color is described through entries on colorimetry, color spaces, color difference metrics, color appearance models, color order systems and cognitive color. The encyclopedia also has extensive coverage of applications throughout industry, including color imaging, color capture, display and printing, and descriptions of color encodings, color management, processing color and applications relating to color synthesis for computer graphics are included. The broad scope of the work is illustrated through entries on color in art conservation, color and architecture, color and education, color and culture, and biographies of some of the key figures involved in color research throughout history. With over 250 entries from color science researchers across academia and industry, this expanded 2nd edition of the Encyclopedia of Color Science and Technology remains the most important single resource in color science.
Download or read book Color Vision written by Karl R. Gegenfurtner and published by Cambridge University Press. This book was released on 2001-05-28 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt: Color Vision, first published in 2000, defines the state of knowledge about all aspects of human and primate color vision.
Download or read book The Oxford Compendium of Visual Illusions written by Arthur G. Shapiro and published by Oxford University Press. This book was released on 2016-11-30 with total page 833 pages. Available in PDF, EPUB and Kindle. Book excerpt: Visual illusions cut across academic divides and popular interests: on the one hand, illusions provide entertainment as curious tricks of the eye; on the other hand, scientific research related to illusory phenomena has given generations of scientists and artists deep insights into the brain and principles of mind and consciousness. Numerous thinkers (including Aristotle, Descartes, Da Vinci, Escher, Goethe, Galileo, Helmholtz, Maxwell, Newton, and Wittgenstein) have been lured by the apparent simplicity of illusions and the promise that illusory phenomena can elucidate the puzzling relationship between the physical world and our perceptual reality. Over the past thirty years, advances in imaging and electrophysiology has dramatically expanded the range of illusions and enabled new forms of analysis, thereby creating new and exciting ways to consider how the brain constructs our perceptual world. The Oxford Compendium of Visual Illusions is a collection of over one hundred chapters about illusions, displayed and discussed by the researchers who invented and conducted research on the illusions. Chapters include full-color images, associated videos, and extensive references. The book is divided into eleven sections: first, a presentation of general history and viewpoints on illusions, followed by sections on geometric, color, motion, space, faces, and cross-category illusions. The book will be of interest to vision scientists, neuroscientists, psychologists, physicists, philosophers, artists, designers, advertisers, and educators curious about applied aspects of visual perception and the brain.
Download or read book The Oxford Compendium of Visual Illusions written by Arthur Gilman Shapiro and published by Oxford University Press. This book was released on 2017 with total page 833 pages. Available in PDF, EPUB and Kindle. Book excerpt: Visual illusions are compelling phenomena that draw attention to the brain's capacity to construct our perceptual world. The Compendium is a collection of over 100 chapters on visual illusions, written by the illusion creators or by vision scientists who have investigated mechanisms underlying the phenomena. --
Download or read book Hierarchical Object Representations in the Visual Cortex and Computer Vision written by Antonio Rodríguez-Sánchez and published by Frontiers Media SA. This book was released on 2016-06-08 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past 40 years, neurobiology and computational neuroscience has proved that deeper understanding of visual processes in humans and non-human primates can lead to important advancements in computational perception theories and systems. One of the main difficulties that arises when designing automatic vision systems is developing a mechanism that can recognize - or simply find - an object when faced with all the possible variations that may occur in a natural scene, with the ease of the primate visual system. The area of the brain in primates that is dedicated at analyzing visual information is the visual cortex. The visual cortex performs a wide variety of complex tasks by means of simple operations. These seemingly simple operations are applied to several layers of neurons organized into a hierarchy, the layers representing increasingly complex, abstract intermediate processing stages. In this Research Topic we propose to bring together current efforts in neurophysiology and computer vision in order 1) To understand how the visual cortex encodes an object from a starting point where neurons respond to lines, bars or edges to the representation of an object at the top of the hierarchy that is invariant to illumination, size, location, viewpoint, rotation and robust to occlusions and clutter; and 2) How the design of automatic vision systems benefit from that knowledge to get closer to human accuracy, efficiency and robustness to variations.
Download or read book Light Vision Color written by Arne Valberg and published by John Wiley & Sons. This book was released on 2007-02-03 with total page 474 pages. Available in PDF, EPUB and Kindle. Book excerpt: Light Vision Color takes a well-balanced, interdisciplinary approach to our most important sensory system. The book successfully combines basics in vision sciences with recent developments from different areas such as neuroscience, biophysics, sensory psychology and philosophy. Originally published in 1998 this edition has been extensively revised and updated to include new chapters on clinical problems and eye diseases, low vision rehabilitation and the basic molecular biology and genetics of colour vision. Takes a broad interdisciplinary approach combining basics in vision sciences with the most recent developments in the area Includes an extensive list of technical terms and explanations to encourage student understanding Successfully brings together the most important areas of the subject in to one volume
Download or read book Colour and Form Perception Straddling the Boundary written by Galina V. Paramei and published by Frontiers Media SA. This book was released on 2016-05-31 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: Starting from psychophysics, over the last 50 years, most progress in unravelling the mechanisms of color vision has been made through the study of single cell responses, mainly in LGN and striate cortex. A similar development in the study of form perception may seem to be underway, centred on the study of temporal cortex. However, because of the combinatorial characteristics of form perception, we are also observing the opposite tendency: from single-cell activity to population coding, and from static receptive field structures to system dynamics and integration and, ultimately, a synthetic form of psychophysics of color and form perception. From single cells to system integration: it is this development the present Research Topic wishes to highlight and promote. How does this development affect our views on the various attributes of perception? In particular, we are interested in to what extent evolving knowledge in the field of color perception is relevant within a developing integrative framework of form perception. The goal of this Research Topic is to bring together experimental research encompassing both color and form perception. For this volume, we planned a broad scope of topics – on color in complex scenes, color and form, as well as dynamic aspects of form perception. We expect that the Research Topic will be attractive to the community of researchers whose work straddles the boundary between the two visual perception fields, as well as to the wider community interested in integrative/systems neuroscience.
Download or read book Speaking of Colors and Odors written by Martina Plümacher and published by John Benjamins Publishing. This book was released on 2007-01-01 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt: How to speak of colors and odors? In many cases, we have to think about an adequate description of a perceived odor or shade of color. Words are not fluently available.The contributions discuss color and odor perception and its linguistic representation from different disciplinary angles: from neurobiology, neuropsychology, psycholinguistics, cognitive linguistics and philosophy. They show that linguistic representation of colors and odors depends highly on cultures of communication. Experts are skilled in discerning finer differences between their sense impressions and have at their disposal a special language which non-experts do not master. The color and odor vocabulary is rare, if there is no cultural habit to communicate the very sense impression. In cases where individuals have to speak of their sensory experiences more precisely they often turn to metaphors. The contributions discuss the lack of inter-individual conventions of naming and describing odors compared to the more expanded linguistic representation of colors.
Download or read book Filling In written by Luiz Pessoa and published by Oxford University Press. This book was released on 2003-02-27 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: The best example of filling-in involves the blind spot, a region of the retina devoid of photoreceptors. Remarkably, the region of visual space corresponding to the blind spot is not perceived as a dark region in space, but instead as having the same color and texture as the surrounding background; hence the expression "filling in." While this type of perceptual completion phenomenon is common in the visual domain, it is argued by the leading scientists who contribute to this book that forms of filling-in also take place in other sensory modalities, including the auditory, somatosensory, and motor systems. In a concluding chapter an integrative approach is taken, which attempts to provide a common framework for completion phenomena occurring on a fast time scale, and cortical reorganization in sensory and motor cortex induced by peripheral damage or skill learning taking place on a slower time scale. It is proposed that systematic changes in the interplay between inhibitory and excitatory inputs permit cortical neurons to become driven by new sources of input, which, in addition to initial perceptual consequences can lead to a long-term structural reorganization of cortex. This book represents a truly interdisciplinary approach to neuroscience, with chapters covering computational modeling, visual psychophysics, functional brain imaging, single-cell physiology, and clinical patient cases. It will be of interest to researchers and graduate students in systems neuroscience, cognitive neuroscience, vision science, neuroimaging, perceptual psychology, computational neuroscience, and philosophy of mind.
Download or read book Webvision written by and published by . This book was released on 2007 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Foundations of Vision written by Brian A. Wandell and published by Sinauer Associates, Incorporated. This book was released on 1995 with total page 508 pages. Available in PDF, EPUB and Kindle. Book excerpt: Designed for students, scientists and engineers interested in learning about the core ideas of vision science, this volume brings together the broad range of data and theory accumulated in this field.
Download or read book The Visual Neurosciences written by John Simon Werner and published by MIT Press. This book was released on 2004 with total page 975 pages. Available in PDF, EPUB and Kindle. Book excerpt: An essential reference book for visual science.
Download or read book Neuromorphic Engineering written by Elishai Ezra Tsur and published by CRC Press. This book was released on 2021-08-27 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: The brain is not a glorified digital computer. It does not store information in registers, and it does not mathematically transform mental representations to establish perception or behavior. The brain cannot be downloaded to a computer to provide immortality, nor can it destroy the world by having its emerged consciousness traveling in cyberspace. However, studying the brain's core computation architecture can inspire scientists, computer architects, and algorithm designers to think fundamentally differently about their craft. Neuromorphic engineers have the ultimate goal of realizing machines with some aspects of cognitive intelligence. They aspire to design computing architectures that could surpass existing digital von Neumann-based computing architectures' performance. In that sense, brain research bears the promise of a new computing paradigm. As part of a complete cognitive hardware and software ecosystem, neuromorphic engineering opens new frontiers for neuro-robotics, artificial intelligence, and supercomputing applications. This book will present neuromorphic engineering from three perspectives: the scientist, the computer architect, and the algorithm designer. We will zoom in and out of the different disciplines, allowing readers with diverse backgrounds to understand and appreciate the field. Overall, the book will cover the basics of neuronal modeling, neuromorphic circuits, neural architectures, event-based communication, and the neural engineering framework. Readers will have the opportunity to understand the different views over the inherently multidisciplinary field of neuromorphic engineering.
Download or read book Perception beyond Inference written by Liliana Albertazzi and published by MIT Press. This book was released on 2023-09-19 with total page 463 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proposing a new paradigm for perceptual science that goes beyond standard information theory and digital computation. This book breaks with the conventional model of perception that views vision as a mere inference to an objective reality on the basis of "inverse optics." The authors offer the alternative view that perception is an expressive and awareness-generating process. Perception creates semantic information in such a way as to enable the observer to deal efficaciously with the chaotic and meaningless structure present at the physical boundary between the body and its surroundings. Vision is intentional by its very nature; visual qualities are essential and real, providing an aesthetic and meaningful interface to the structures of physics and the state of the brain. This view brings perception firmly in line with ethology and modern evolutionary biology and suggests new approaches in all disciplines that study, or require an understanding of, the ontology of mind. The book is the joint effort of a multidisciplinary group of authors. Topics covered include the relationships among stimuli, neuronal processes, and visual awareness. After considering the mind-dependent growing of information, the book treats time and dynamics; color, shape, and space; language and perception; perception, art, and design.
