Dissertation/ Thesis

The role of orientation diversity in binocular vergence control

Bibliographic Details
Title: The role of orientation diversity in binocular vergence control
Authors: Qu, Chao
Publication Year: 2011
Collection: The Hong Kong University of Science and Technology: HKUST Institutional Repository
Subject Terms: Binocular vision, Stereoscopic views, Visual perception -- Data processing, Orientation
Description: Neurons tuned to binocular disparity in area V1 are hypothesized to be responsible for short latency binocular vergence movements, which align the two eyes on the same object as it moves in depth. Disparity selective neurons in V1 are not only selective to disparity, but also to other visual stimulus dimensions, in particular orientation. In this work, we explore the role of neurons tuned to different orientations in binocular vergence control. We train an artificial binocular vision system to execute corrective vergence movements based on the outputs of disparity selective neurons tuned to different orientations and scales. We find that neurons tuned to non-vertical orientations have strong effect on the vergence eye movements. Although adding neurons tuned to non-vertical orientations does not appear to improve vergence tracking accuracy, we find that neurons tuned to non-vertical orientations still play critical roles in binocular vergence control. First, they increase the robustness of policy to the noise. Second, they also increase the effective range of vergence control. We also compare the effect of different learning algorithms for the control policy. In particular, we compare the use of Attention Gated Reinforcement Learning (AGReL) method, which was used in prior work on this task, with the Natural Actor-Critic method. We show that the performance of the Natural Actor-Critic method surpasses that of AGReL. Although based upon the same input, control policies learned by AGReL can only exploit information about the sign of stereo disparity while the control policies learned by the Natural Actor-Critic method can exploit information about both the sign and magnitude of stereo disparity, leading to faster system responses. Using the Natural Actor-Critic algorithm, we show that the addition of non-vertically oriented disparity selective neurons enables the use of a wider range of vergence commands, which also speeds up the system. Keywords-vergence control, reinforcement learning, orientation diversity
Document Type: thesis
Language: English
Availability: http://repository.hkust.edu.hk/ir/Record/1783.1-7398
https://repository.hkust.edu.hk/ir/bitstream/1783.1-7398/1/b1155585.pdf
Accession Number: edsbas.48D8C063
Database: BASE
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  – Url: http://repository.hkust.edu.hk/ir/Record/1783.1-7398#
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IllustrationInfo
Items – Name: Title
  Label: Title
  Group: Ti
  Data: The role of orientation diversity in binocular vergence control
– Name: Author
  Label: Authors
  Group: Au
  Data: <searchLink fieldCode="AR" term="%22Qu%2C+Chao%22">Qu, Chao</searchLink>
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  Data: 2011
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  Data: The Hong Kong University of Science and Technology: HKUST Institutional Repository
– Name: Subject
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  Data: <searchLink fieldCode="DE" term="%22Binocular+vision%22">Binocular vision</searchLink><br /><searchLink fieldCode="DE" term="%22Stereoscopic+views%22">Stereoscopic views</searchLink><br /><searchLink fieldCode="DE" term="%22Visual+perception+--+Data+processing%22">Visual perception -- Data processing</searchLink><br /><searchLink fieldCode="DE" term="%22Orientation%22">Orientation</searchLink>
– Name: Abstract
  Label: Description
  Group: Ab
  Data: Neurons tuned to binocular disparity in area V1 are hypothesized to be responsible for short latency binocular vergence movements, which align the two eyes on the same object as it moves in depth. Disparity selective neurons in V1 are not only selective to disparity, but also to other visual stimulus dimensions, in particular orientation. In this work, we explore the role of neurons tuned to different orientations in binocular vergence control. We train an artificial binocular vision system to execute corrective vergence movements based on the outputs of disparity selective neurons tuned to different orientations and scales. We find that neurons tuned to non-vertical orientations have strong effect on the vergence eye movements. Although adding neurons tuned to non-vertical orientations does not appear to improve vergence tracking accuracy, we find that neurons tuned to non-vertical orientations still play critical roles in binocular vergence control. First, they increase the robustness of policy to the noise. Second, they also increase the effective range of vergence control. We also compare the effect of different learning algorithms for the control policy. In particular, we compare the use of Attention Gated Reinforcement Learning (AGReL) method, which was used in prior work on this task, with the Natural Actor-Critic method. We show that the performance of the Natural Actor-Critic method surpasses that of AGReL. Although based upon the same input, control policies learned by AGReL can only exploit information about the sign of stereo disparity while the control policies learned by the Natural Actor-Critic method can exploit information about both the sign and magnitude of stereo disparity, leading to faster system responses. Using the Natural Actor-Critic algorithm, we show that the addition of non-vertically oriented disparity selective neurons enables the use of a wider range of vergence commands, which also speeds up the system. Keywords-vergence control, reinforcement learning, orientation diversity
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  Data: http://repository.hkust.edu.hk/ir/Record/1783.1-7398<br />https://repository.hkust.edu.hk/ir/bitstream/1783.1-7398/1/b1155585.pdf
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RecordInfo BibRecord:
  BibEntity:
    Languages:
      – Text: English
    Subjects:
      – SubjectFull: Binocular vision
        Type: general
      – SubjectFull: Stereoscopic views
        Type: general
      – SubjectFull: Visual perception -- Data processing
        Type: general
      – SubjectFull: Orientation
        Type: general
    Titles:
      – TitleFull: The role of orientation diversity in binocular vergence control
        Type: main
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          Name:
            NameFull: Qu, Chao
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            – D: 01
              M: 01
              Type: published
              Y: 2011
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