Read Books Online and Download eBooks, EPub, PDF, Mobi, Kindle, Text Full Free.
Some Properties Of Spatial Frequency Mechanismsin The Human Visual System
Download Some Properties Of Spatial Frequency Mechanismsin The Human Visual System full books in PDF, epub, and Kindle. Read online Some Properties Of Spatial Frequency Mechanismsin The Human Visual System ebook anywhere anytime directly on your device. Fast Download speed and no annoying ads. We cannot guarantee that every ebooks is available!
Book Synopsis Some Properties of Spatial Frequency Mechanisms?in the Human Visual System by : M. N. Williams
Download or read book Some Properties of Spatial Frequency Mechanisms?in the Human Visual System written by M. N. Williams and published by . This book was released on 1984 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis A Study of the Spatial Frequency Analyzing Characteristics of the Human Visual System by : Jean Adelaide Tkach
Download or read book A Study of the Spatial Frequency Analyzing Characteristics of the Human Visual System written by Jean Adelaide Tkach and published by . This book was released on 1985 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Properties of Human Visual Spatial Frequency Selective Systems by : Joyce Chapin Hirsch
Download or read book Properties of Human Visual Spatial Frequency Selective Systems written by Joyce Chapin Hirsch and published by . This book was released on 1977 with total page 584 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Representations of Spatial Frequency, Depth, and Higher-level Image Content in Human Visual Cortex by : Daniel E. Berman
Download or read book Representations of Spatial Frequency, Depth, and Higher-level Image Content in Human Visual Cortex written by Daniel E. Berman and published by . This book was released on 2018 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: The human visual system has been studied in great detail for millennia, but there are substantial, unanswered questions regarding the underlying characteristics of such an important sensory system. Many of these unanswered questions involve the neural correlates in which low-level features are processed in higher-level visual areas. Here, we use functional magnetic resonance imaging (fMRI) to address some of these questions concerning depth and spatial frequency perception in order to elucidate upon such fundamental aspects of visual processing and the mechanisms in which we are able to perceive the world around us. In Chapter 2, we examine the neural correlates of scene content with regards to the spatial frequency contained in these scenes. It has been long debated whether low or high spatial frequencies are what primarily represent the content of a scene and how different scene selective areas such as parahippocampal place area (PPA), retrospenial cortex (RSC) and occipital place area (OPA) process this component of the image we are viewing. Both low and high spatial frequencies contribute to scene representations, but what we find using both univariate and multivariate pattern analysis (MVPA) is that scene content is primarily represented throughout the majority of visual cortex via high spatial frequency information. Interestingly, we find that the posterior portion of PPA may have a unique role in processing low-level features like spatial frequency. Next, we address depth perception, another element of our visual system that is not fully understood. In Chapter 3 we examine whether category-selective areas such as scene-selective areas PPA, RSC and OPA, object-selective area lateral occipital cortex (LOC), face-selective areas fusiform face area (FFA) and occipital face area (OFA), and motion area (MT), are sensitive to a stimulus’ position-in-depth. We find that the scene areas prefer stimuli both behind and in front of fixation, while areas MT and LOC prefer front stimuli. Finally, in Chapter 4 we will examine whether depth representations are organized in a topographical (or “map-like”) manner. Much like classic retinotopic maps defined throughout visual cortex that are based on polar angle and eccentricity measurements utilizing 2-dimensional stimuli, we also find “depthotopic” maps using analogous methodology and analyses, known as phase-encoding mapping, The main modification is that our stimulus periodically cycles through different positions in depth instead of the x and y coordinates of visual field. These experiments provide us with a greater understanding of the neural correlates in which spatial frequency and depth are processed in high-level areas of human visual cortex.
Book Synopsis Spatial Vision by : Russell L. De Valois
Download or read book Spatial Vision written by Russell L. De Valois and published by . This book was released on 1988 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Designed to present neuroscientists, cognitive psychologists and ophthalmologists with an integrated view of how humans perceive the spatial relations in their visual world, this study covers anatomical, physiological, psychological and perceptual aspects.
Book Synopsis Spatial Vision by : Russell L. DeValois
Download or read book Spatial Vision written by Russell L. DeValois and published by Oxford University Press. This book was released on 1990-08-09 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume presents an integrated view of how we perceive the spatial relations in our visual world, covering anatomical, physiological, psychophysical, and perceptual aspects. The authors discuss the visual system primarily in terms of spatial frequency analysis using a linear systems approach. They review evidence supporting a local, patch-by-patch spatial frequency filtering of visual information rather than the global Fourier analysis other researchers have proposed. A separate chapter addresses the special issues surrounding color vision, and a brief, nonmathematical introduction to linear systems analysis is included for the uninitiated reader.
Book Synopsis Spatial Frequency Processing in the Human Visual System by : Robert L. Seyfert
Download or read book Spatial Frequency Processing in the Human Visual System written by Robert L. Seyfert and published by . This book was released on 1980 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The human visual system responses to resolution targets whose small area spatial content has been altered from white to black has been investigated. Modified tri-bar targets were presented to observers on a rear projection screen at constant average luminance and varying levels of contrast. Each observer was asked to determine if he could see the target and if the target had been modified. Responses indicate that there is no difference in the visibility of targets in which small areas have been changed to white or black but whose spatial frequency content is the same."--Abstract.
Book Synopsis Optical System Design, Analysis, and Production by : Philip J. Rogers
Download or read book Optical System Design, Analysis, and Production written by Philip J. Rogers and published by . This book was released on 1983 with total page 478 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Relationships Between Perceptual Mechanisms for Color and Pattern in Human Vision by : Seija Haapasalo
Download or read book Relationships Between Perceptual Mechanisms for Color and Pattern in Human Vision written by Seija Haapasalo and published by Helsinki : Suomalainen Tiedeakatemia : Distribution, Akateeminen Kirjakauppa. This book was released on 1982 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Properties of Spatial Vision with Luminance Or Color Varying Patterns by : Michael Anderson Webster
Download or read book Properties of Spatial Vision with Luminance Or Color Varying Patterns written by Michael Anderson Webster and published by . This book was released on 1988 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Spatial Properties of Fine-grain Movement Perception in the Human Visual System by : A. Tomoszek
Download or read book Spatial Properties of Fine-grain Movement Perception in the Human Visual System written by A. Tomoszek and published by . This book was released on 1989 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Higher-Order Processing in the Visual System by : Gregory R. Bock
Download or read book Higher-Order Processing in the Visual System written by Gregory R. Bock and published by John Wiley & Sons. This book was released on 2008-04-30 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt: Foremost neurophysiologists and psychophysicists provide pertinent information on the nature of representation at the earliest stages as this will constrain the disposition of all subsequent processing. This processing is discussed in several different types of visual perception.
Book Synopsis Spatial Frequency Channels in the Human Visual System by : Norma Van Surdam Graham
Download or read book Spatial Frequency Channels in the Human Visual System written by Norma Van Surdam Graham and published by . This book was released on 1970 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Temporal and Spatial Properties of Shape Processing in the Human Visual Cortex by : Elisabeth Huberle
Download or read book Temporal and Spatial Properties of Shape Processing in the Human Visual Cortex written by Elisabeth Huberle and published by . This book was released on 2006 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Spatiotemporal Properties of the Visual System and the Effect of Attention by : Patricia Anne Costello
Download or read book Spatiotemporal Properties of the Visual System and the Effect of Attention written by Patricia Anne Costello and published by . This book was released on 2003 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Contribution of Psychophysical Spatial Frequency Channels to the Discrimination of Broadband Contrast by : Bruno Richard
Download or read book The Contribution of Psychophysical Spatial Frequency Channels to the Discrimination of Broadband Contrast written by Bruno Richard and published by . This book was released on 2016 with total page 223 pages. Available in PDF, EPUB and Kindle. Book excerpt: The design and function of the human visual system is thought to have been shaped by the environment and tasks humans have performed throughout evolution and experience. Thus, it is important to establish the association between the properties of natural scenes and the responses of the visual system to these features at a behaviourally relevant level (e.g., psychophysically). A relevant property of natural scenes - which human observers are sensitive to - is the slope of the orientation averaged Fourier amplitude spectrum (?). It characterizes the decrease in amplitude as a function of spatial frequency (1/f?), and has an average value of 1.0 (on logarithmic axes) in natural scenes. The process of detecting a change in ? is thought to stem from the activity of one or more spatial frequency channels, but their exact contribution remains to be defined. The overarching goal of this dissertation was to assess the contribution of spatial frequency channels to the detection, and discrimination, of a change in ?. We first set out to obtain psychophysical evidence that ? discrimination thresholds were dependent on the spatial frequency content of noise stimuli with 1/f amplitude spectra. Our results showed that while all spatial frequency channels contribute to ? discrimination, the channel(s) of most influence seem to correlate in peak spatial frequency to the dominant perceptual scale of the noise image. While the contribution of low spatial frequency channels discrimination of steep ?s was evident from our data, the influence of higher spatial frequency channels to the discrimination of shallower ?s was not. In an attempt to better isolate the role of high spatial frequency channels, we attempted to modulate their activity with trans-cranial Direct Current Stimulation (tDCS) and change ? discrimination thresholds. However, while this technique is capable of modulating channels to alter contrast detection, we found tDCS to be an ill-suited technique to alter the response characteristics of channels under suprathreshold conditions (i.e., broadband noise discrimination). As a final effort to isolate the contribution of spatial frequency channels to the discrimination of broadband contrast, we used a classification image paradigm to understand how different spatial frequencies contribute to the identification of a change in ?. Interestingly, this method revealed task dependent contributions of spatial frequency channels to the discrimination of ?. The identification of ? is specific to ?, in that increments and decrements in contrast in specific spatial frequency bands signal for particular ?s, while the identification of a change in ? (i.e., discrimination) was not specific to ?. Regardless of the reference ?, observers used an increment in contrast in low spatial frequency bands and decrement of contrast in higher spatial frequency bands to identify the odd stimulus. Taken together, these findings demonstrate that the discrimination of ? is unspecific to ?. Observers to rely on differences in contrast between low and high spatial frequency bands to detect a change in ?, but may not be particularly tuned to certain ? values as has previously been argued.
Author :National Institutes of Health (U.S.). Division of Research Grants Publisher : ISBN 13 : Total Pages :1224 pages Book Rating :4.3/5 (91 download)
Book Synopsis Research Grants Index by : National Institutes of Health (U.S.). Division of Research Grants
Download or read book Research Grants Index written by National Institutes of Health (U.S.). Division of Research Grants and published by . This book was released on 1975 with total page 1224 pages. Available in PDF, EPUB and Kindle. Book excerpt: