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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Quiet Eye Training and the Focus of Visual Attention in Golf Putting

January 2019 (has links)
abstract: Previous research has shown that training visual attention can improve golf putting performance. A technique called the Quiet Eye focuses on increasing a player’s length of fixation between the ball and the hole. When putting, the final fixation is made on the ball before executing the stroke leaving players to rely on their memory of the hole’s distance and location. The present study aimed to test the effectiveness of Quiet Eye training for final fixation on the hole. Twelve Arizona State University (ASU) students with minimal golf experience putted while wearing eye tracking glasses under the following conditions: from three feet with final fixation on the ball, from six feet with final fixation on the ball, from three feet with final fixation on the hole and from six feet with final fixation on the hole. Participant’s performance was measured before training, following quiet eye training, and under simulated pressure conditions. Putting performance was not significantly affected by final fixation for all conditions. The number of total putts made was significantly greater when putting from three feet for all conditions. Future research should test the effects of this training with expert golfers whose processes are more automatic compared to novices and can afford to look at the hole while putting. / Dissertation/Thesis / Masters Thesis Human Systems Engineering 2019
22

Data and Model-Driven Selection Using Color Regions

Syeda-Mahmood, Tanveer Fathima 01 February 1992 (has links)
A key problem in model-based object recognition is selection, namely, the problem of determining which regions in the image are likely to come from a single object. In this paper we present an approach that extracts and uses color region information to perform selection either based solely on image- data (data-driven), or based on the knowledge of the color description of the model (model -driven). The paper presents a method of perceptual color specification by color categories to extract perceptual color regions. It also discusses the utility of color-based selection in reducing the search involved in recognition.
23

Vision, Instruction, and Action

Chapman, David 01 April 1990 (has links)
This thesis describes Sonja, a system which uses instructions in the course of visually-guided activity. The thesis explores an integration of research in vision, activity, and natural language pragmatics. Sonja's visual system demonstrates the use of several intermediate visual processes, particularly visual search and routines, previously proposed on psychophysical grounds. The computations Sonja performs are compatible with the constraints imposed by neuroscientifically plausible hardware. Although Sonja can operate autonomously, it can also make flexible use of instructions provided by a human advisor. The system grounds its understanding of these instructions in perception and action.
24

Visual Attention-based Small Screen Adaptation for H.264 Videos

Mukherjee, Abir January 2008 (has links)
We develop a framework that uses visual attention analysis combined with temporal coherence to detect the attended region from a H.264 video bitstream, and display it on a small screen. A visual attention module based upon Walther and Koch's model gives us the attended region in I-frames. We propose a temporal coherence matching framework that uses the motion information in P-frames to extend the attended region over the H.264 video sequence. Evaluations show encouraging results with over 80% successful detection rate for objects of interest, and 85% respondents claiming satisfactory output.
25

Studies of Visual Attention

Bora, Archana 17 June 2009 (has links)
Aim The experiment proposed to study the effect of sustained visual attention in an effective visual field of 40 degrees, in cued and uncued conditions with different set-sizes. Methods The participants had a normal contrast and visual acuity with normal ocular/general health. The experiments were performed both for central (0 - 20degrees) and peripheral (>20 – 50 degrees) visual fields. The targets were presented with valid and invalid cued conditions in different set-sizes of 500, 1000 and 2000. The targets were Gabor gratings oriented at 90 or 180deg subtending a minimum angle of resolution (MAR) ranging from 1.5-10minarc at 25cm. The spatial frequency of the Gabor ranged from 1- 29cycles/degrees and contrast from 20-100%. The observer had to identify the Gabor with horizontal grating and register the response. The accuracy and the reaction times for the targets were evaluated. Results The central targets had lower reaction times and high accuracy compared to the peripheral targets. There was a significantly increasing eccentricity effect as the targets were displayed much peripherally. It was less with presentation of valid sustained cues but it was not eliminated. The diminishing contrast of the target had a significant increase in reaction times and reduced accuracy. The effect of increasing number of items in the display didn’t show any significant increase in reaction time, i.e. there was no “set-size effect” seen both central and peripheral targets. The valid cues improved the performance with lower reaction times, compared to the neutral cued conditions, in each of the different experiments and resulted in an improved accuracy in both the central and peripheral visual field. Conclusion Visual attention is affected by contrast, target size and spatial gratings. Reaction time is high and accuracy less for low contrast targets, high spatial frequency and larger set-size, except for set-size 2000 in the central field where it was seen that the reaction times were reduced. The effect is consistent in both central and peripheral visual fields. The set-size also has an effect on the reaction times and on accuracy. The effects are more pronounced in the peripheral visual field.
26

Investigating the effect of in-store print advertising on consumer’s visual attention using eye-tracking technology

Rahimi, Ramin January 2012 (has links)
Due to rising number of products on the shelves of stores and the fact that about 70% of buying decisions are made at the point-of-purchase, retailers and marketers are growingly investing on in-store advertising material to grab their customers’ attention. Thus, measuring the effectiveness of the in-store material in catching consumers’ attention would be highly of interest of marketers. In this study we have investigated the priming effect of in-store print advertisement on the visual attention of consumers. An experiment was conducted in a Swedish retail store where using eye-tracking technology, the visual behavior of two groups of participants who had been exposed to in-store product signs was captured. The results of this study shows that participants who had looked at a product sign, noted (fixated at least once) that product on the shelf earlier while the number of fixations on the target products was not directly influenced. An implication for managers is that they can use in-store product signs to manipulate the visual attention of consumers in a way that designated brands are attended earlier.
27

Visual Attention-based Small Screen Adaptation for H.264 Videos

Mukherjee, Abir January 2008 (has links)
We develop a framework that uses visual attention analysis combined with temporal coherence to detect the attended region from a H.264 video bitstream, and display it on a small screen. A visual attention module based upon Walther and Koch's model gives us the attended region in I-frames. We propose a temporal coherence matching framework that uses the motion information in P-frames to extend the attended region over the H.264 video sequence. Evaluations show encouraging results with over 80% successful detection rate for objects of interest, and 85% respondents claiming satisfactory output.
28

Studies of Visual Attention

Bora, Archana 17 June 2009 (has links)
Aim The experiment proposed to study the effect of sustained visual attention in an effective visual field of 40 degrees, in cued and uncued conditions with different set-sizes. Methods The participants had a normal contrast and visual acuity with normal ocular/general health. The experiments were performed both for central (0 - 20degrees) and peripheral (>20 – 50 degrees) visual fields. The targets were presented with valid and invalid cued conditions in different set-sizes of 500, 1000 and 2000. The targets were Gabor gratings oriented at 90 or 180deg subtending a minimum angle of resolution (MAR) ranging from 1.5-10minarc at 25cm. The spatial frequency of the Gabor ranged from 1- 29cycles/degrees and contrast from 20-100%. The observer had to identify the Gabor with horizontal grating and register the response. The accuracy and the reaction times for the targets were evaluated. Results The central targets had lower reaction times and high accuracy compared to the peripheral targets. There was a significantly increasing eccentricity effect as the targets were displayed much peripherally. It was less with presentation of valid sustained cues but it was not eliminated. The diminishing contrast of the target had a significant increase in reaction times and reduced accuracy. The effect of increasing number of items in the display didn’t show any significant increase in reaction time, i.e. there was no “set-size effect” seen both central and peripheral targets. The valid cues improved the performance with lower reaction times, compared to the neutral cued conditions, in each of the different experiments and resulted in an improved accuracy in both the central and peripheral visual field. Conclusion Visual attention is affected by contrast, target size and spatial gratings. Reaction time is high and accuracy less for low contrast targets, high spatial frequency and larger set-size, except for set-size 2000 in the central field where it was seen that the reaction times were reduced. The effect is consistent in both central and peripheral visual fields. The set-size also has an effect on the reaction times and on accuracy. The effects are more pronounced in the peripheral visual field.
29

The role of uncertainty and reward on eye movements in natural tasks

Sullivan, Brian Thomas 18 July 2012 (has links)
The human visual system is remarkable for the variety of functions it can be used for and the range of conditions under which it can perform, from the detection of small brightness changes to guiding actions in complex movements. The human eye is foveated and humans continually make eye and body movements to acquire new visual information. The mechanisms that control this acquisition and the associated sequencing of eye movements in natural circumstances are not well understood. While the visual system has highly parallel inputs, the fovea must be moved in a serial fashion. A decision process continually occurs where peripheral information is evaluated and a subsequent fixation target is selected. Prior explanations for fixation selection have largely focused on computer vision algorithms that find image areas with high salience, ones that incorporate reduction of uncertainty or entropy of visual features, as well as heuristic models. However, these methods are not well suited to model natural circumstances where humans are mobile and eye movements are closely coordinated for gathering ongoing task information. Following a computational model of gaze scheduling proposed by Sprague and Ballard (2004), I argue that a systematic explanation of human gaze behavior in complex natural tasks needs to represent task goals, a reward structure for these goals and a representation of uncertainty concerning progress towards those goals. If these variables are represented it is possible to formulate a decision computation for choosing fixation targets based on an expected value from uncertainty weighted reward. I present two studies of human gaze behavior in a simulated driving task that provide evidence of the human visual system’s sensitivity to uncertainty and reward. In these experiments observers tended to more closely monitor an information source if it had a high level of uncertainty but only for information also associated with high reward. Given this behavioral finding, I then present a set of simple candidate models in an attempt to explain how humans schedule the acquisition of information over time. These simple models are shown to be inadequate in describing the process of coordinated information acquisition in driving. I present an extended version of the gaze scheduling model adapted to our particular driving task. This formulation allows ordinal predictions on how humans use reward and uncertainty in the control of eye movements and is generally consistent with observed human behavior. I conclude by reviewing main results and discussing the merits and benefits of the computational models used, possible future behavioral experiments that would serve to more directly test the gaze scheduling model, as well as revisions to future implementations of the model to more appropriately capture human gaze behavior. / text
30

Visual Attention to Reproductively Relevant Stimuli: The Role of Sex-Linked Biological and Social Factors

Charles, Nora 2011 December 1900 (has links)
Research examining interest in stimuli associated with evolved reproductive motivations has demonstrated sex differences in preferences for potential mates and infants, as well as traits and states associated with increased attention to same-sex rivals. Manipulations of reproductive motivations (e.g., mate searching) have also been shown to affect visual attention to these types of stimuli. Most of this work has focused on physical attractiveness in adult targets, which evolutionary theories of mate preferences suggest is less important than social status for women's mate selection, and no research to date has measured patterns of visual attention to infants. Additionally, the stimuli used in past research tend to have low ecological validity and it is not known whether the preferences displayed generalize to the perception of more realistic stimuli. Finally, the potential effects of circulating testosterone on attention to reproductively relevant stimuli have been studied only in very limited ways in men. In the current project, participants self-reported personality traits and characteristics associated with relationships and sexuality, provided samples for analysis of circulating testosterone, were selected to undergo either a jealousy inducing or anxiety-inducing priming task, and were shown low and high ecological validity stimuli displaying reproductively relevant figures. Major findings include more similarity between the sexes than is usually assumed and weaker preferences for potential mates with high mate value in high ecological validity scenes than low ecological validity scenes. Suggestions for future research include applying the theory of strategic pluralism to within-person variability in attention to reproductively relevant stimuli.

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