Saccade Mechanism Based on Processes for Depth Estimation and Incongruity Detection between Binocular Retinal Images – Analysis of Gazing Positions and Inter-saccade Intervals –

1997 ◽  
Vol 9 (2) ◽  
pp. 111-120
Author(s):  
Hiroaki Kudo ◽  
◽  
Kenya Uomori ◽  
Mitsuho Yamada ◽  
Noboru Ohnishi ◽  
...  
Keyword(s):  
Visual Processing ◽  
Early Stage ◽  
Depth Estimation ◽  
Retinal Images ◽  
Fixation Target ◽  
Occlusion Detection ◽  
Detection Mechanism ◽  
Left And Right

We analyzed binocular gazing positions in the existence of a rim occlusion. When a human gazes at the rim of a textured cylinder, the gazing position shifts from the fixation target, When a human gazes at the rim of a cylinder whose upper-surface is visible, the gazing points are located at the estimated surface's depth. In this paper, to investigate the mechanism changing the gazing point, we analyzed inter-saccade intervals. The result shows that an occlusion detection mechanism exists at an early stage of human visual processing, and the mechanism causes a shorter-interval saccade when incongruity regions between left and right retinal images are detected. We propose a saccade mechanism which includes processes for depth estimation and incongruity detection between binocular retinal images based on relationships between the gazing positions and the results of inter-saccade intervals.

Computing with Self-Excitatory Cliques: A Model and an Application to Hyperacuity-Scale Computation in Visual Cortex

1999 ◽  
Vol 11 (1) ◽  
pp. 21-66 ◽  
Author(s):  
Douglas A. Miller ◽  
Steven W. Zucker
Keyword(s):  
Visual Processing ◽  
Network Architecture ◽  
Early Stage ◽  
Cortical Cell ◽  
Pyramidal Cells ◽  
Direct Calculation ◽  
Formal Theory ◽  
Cortical Cells ◽  
Cell Counts ◽  
Spatiotemporal Response

We present a model of visual computation based on tightly inter-connected cliques of pyramidal cells. It leads to a formal theory of cell assemblies, a specific relationship between correlated firing patterns and abstract functionality, and a direct calculation relating estimates of cortical cell counts to orientation hyperacuity. Our network architecture is unique in that (1) it supports a mode of computation that is both reliable and efficent; (2) the current-spike relations are modeled as an analog dynamical system in which the requisite computations can take place on the time scale required for an early stage of visual processing; and (3) the dynamics are triggered by the spatiotemporal response of cortical cells. This final point could explain why moving stimuli improve vernier sensitivity.

The “Mosaic Stage” in Amodal Completion as Characterized by Magnetoencephalography Responses

2006 ◽  
Vol 18 (8) ◽  
pp. 1394-1405 ◽  
Author(s):  
Gijs Plomp ◽  
Lichan Liu ◽  
Cees van Leeuwen ◽  
Andreas A. Ioannides
Keyword(s):  
Neural Activity ◽  
Visual Processing ◽  
Early Stage ◽  
Amodal Completion ◽  
Peak Latency ◽  
Per Se

We investigated the process of amodal completion in a same-different experiment in which test pairs were preceded by sequences of two figures. The first of these could be congruent to a global or local completion of an occluded part in the second figure, or a mosaic interpretation of it. We recorded and analyzed the magnetoencephalogram for the second figures. Compared to control conditions, in which unrelated primes were shown, occlusion and mosaic primes reduced the peak latency and amplitude of neural activity evoked by the occlusion patterns. Compared to occlusion primes, mosaic ones reduced the latency but increased the amplitude of evoked neural activity. Processes relating to a mosaic interpretation of the occlusion pattern, therefore, can dominate in an early stage of visual processing. The results did not provide evidence for the presence of a functional “mosaic stage” in completion per se, but characterize the mosaic interpretation as a qualitatively special one that can rapidly emerge in visual processing when context favors it.

scholarly journals Visual attention spreads broadly but selects information locally

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Satoshi Shioiri ◽  
Hajime Honjyo ◽  
Yoshiyuki Kashiwase ◽  
Kazumichi Matsumiya ◽  
Ichiro Kuriki
Keyword(s):  
Visual Attention ◽  
Spatial Attention ◽  
Visual Processing ◽  
Early Stage ◽  
Event Related Potential ◽  
Spatial Spread ◽  
Local Selection ◽  
Unified View ◽  
Behavioral Evidence ◽  
P3 Component

Abstract Visual attention spreads over a range around the focus as the spotlight metaphor describes. Spatial spread of attentional enhancement and local selection/inhibition are crucial factors determining the profile of the spatial attention. Enhancement and ignorance/suppression are opposite effects of attention, and appeared to be mutually exclusive. Yet, no unified view of the factors has been provided despite their necessity for understanding the functions of spatial attention. This report provides electroencephalographic and behavioral evidence for the attentional spread at an early stage and selection/inhibition at a later stage of visual processing. Steady state visual evoked potential showed broad spatial tuning whereas the P3 component of the event related potential showed local selection or inhibition of the adjacent areas. Based on these results, we propose a two-stage model of spatial attention with broad spread at an early stage and local selection at a later stage.

scholarly journals Automatic Analysis of Retinal Vascular Parameters for Detection of Diabetes in Indian Patients with No Retinopathy Sign

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Behzad Aliahmad ◽  
Dinesh Kant Kumar ◽  
Rajeev Jain
Keyword(s):  
Type Ii Diabetes ◽  
Indian Population ◽  
Linear Regression Analysis ◽  
Retinal Images ◽  
Type Ii ◽  
Demographic Information ◽  
Stepwise Linear Regression Analysis ◽  
Explanatory Variables ◽  
Branching Angle ◽  
Left And Right

This study has investigated the association between retinal vascular parameters with type II diabetes in Indian population with no observable diabetic retinopathy. It has introduced two new retinal vascular parameters: total number of branching angles (TBA) and average acute branching angles (ABA) as potential biomarkers of diabetes in an explanatory model. A total number of 180 retinal images (two (left and right) × two (ODC and MC) × 45 subjects (13 diabetics and 32 nondiabetics)) were analysed. Stepwise linear regression analysis was performed to model the association between type II diabetes with the best subset of explanatory variables (predictors), consisting of retinal vascular parameters and patients’ demographic information. P value of the estimated coefficients (P<0.001) indicated that, at α level of 0.05, the newly introduced retinal vascular parameters, that is, TBA and ABA together with CRAE, mean tortuosity, SD of branching angle, and VB, are related to type II diabetes when there is no observable sign of retinopathy.

A Visual Channel Theory Approach to Pilot Performance and Simulator Imagery

1981 ◽  
Vol 25 (1) ◽  
pp. 223-227
Author(s):  
David Regan ◽  
Ronald Kruk ◽  
Ken Beverley ◽  
Tom Longridge
Keyword(s):  
Visual Processing ◽  
Early Stage ◽  
Visual Display ◽  
Flight Simulator ◽  
Theory Approach ◽  
Pilot Performance ◽  
Visual Channel ◽  
Display Design ◽  
Preliminary Study ◽  
Channel Theory

There is a body of experimental evidence supporting the hypothesis that an early stage of visual processing consists of analyzing retinal image information into a number of abstract categories or features, called channels. This paper briefly reviews the channel hypothesis and cites potential implications for flight simulator visual display design. The results of a preliminary study designed to investigate the relationships between channel sensitivity and flight simulator landing performance are presented.

An Automatic Self-Calibration Approach for Wide Baseline Stereo Cameras Using Sea Surface Images

2015 ◽  
Vol 03 (04) ◽  
pp. 277-290 ◽  
Author(s):  
Han Wang ◽  
Wei Mou ◽  
Xiaozheng Mou ◽  
Shenghai Yuan ◽  
Soner Ulun ◽  
...  
Keyword(s):  
Feature Detection ◽  
Depth Estimation ◽  
Calibration Method ◽  
Sea Surface ◽  
Distant Object ◽  
Self Calibration ◽  
Calibration Pattern ◽  
Left And Right ◽  
Calibration Approach ◽  
Surface Images

Stereo rig with wide baseline is necessary when accurate depth estimation for distant object is desired. However, in order to make calibration pattern to be viewed from both left and right cameras, the wider the baseline the bigger the calibration pattern is required. In contrast to the traditional stereo calibration method using calibration pattern, we propose a self-calibration approach that can estimate cameras' rotation matrices for stereo rig with wide baseline (3 m). Given images taken from left and right cameras, the relative roll and pitch angles between two cameras are recovered by aligning sea horizon in left and right images. The pitch angle is estimated by making the projections of one point at infinite distance appear at the same location in both images. A photometric minimization is applied to refine the rotation parameters. Compared with conventional checkerboard-based calibration techniques which require extra equipments or personnel, our approach only needs a pair of sea images. Moreover, unlike most self-calibration approaches, feature detection and matching are not required which makes it possible to apply our approach on featureless images. As a result, it is flexible and easy to implement our approach on sea surface images. Real world experiments demonstrate the feasibility of our approach.

scholarly journals Contribution of Impaired Early-Stage Visual Processing to Working Memory Dysfunction in Adolescents With Schizophrenia

2007 ◽  
Vol 64 (11) ◽  
pp. 1229 ◽  
Author(s):  
Corinna Haenschel ◽  
Robert A. Bittner ◽  
Fabian Haertling ◽  
Anna Rotarska-Jagiela ◽  
Konrad Maurer ◽  
...  
Keyword(s):  
Working Memory ◽  
Visual Processing ◽  
Early Stage ◽  
Memory Dysfunction
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