• Title/Summary/Keyword: Visual system

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The effect of visual information on gait parameters with induced ankle muscle fatigue

  • Suh, Hye Rim;Hwang, Jin-Hee;Lee, Su-Young
    • Physical Therapy Rehabilitation Science
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    • v.6 no.3
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    • pp.140-145
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    • 2017
  • Objective: The purpose of this study was to investigate the effect of visual block with ankle joint fatigue on gait and dynamic balance ability. Design: Cross-sectional study. Methods: Thirty healthy young adults (men=15, women=15) between 22 to 25 years of age voluntarily participated in this study. All subjects performed the gait and dynamic balance test successively in two conditions: the visual block and the open eyes condition. Before the gait and dynamic balance test, muscle fatigue on the ankle joint was induced to all subjects by doing ankle dorsiflexion and plantarflexion alternately, and then gait parameters (step length, stride length, cadence, velocity, single limb support, and double limb support) were assessed by walking on the GAITRite system (CIR Systems Inc., USA). Subjects also performed the functional reach test (FRT) for assessment of dynamic balance. This study examined gait parameters and FRT scores in each visual block and open eyes condition. Results: The results showed that FRT scores with the visual block condition significantly decreased compared to without visual blocking (p<0.01). Step length, stride length, cadence, and velocity of gait parameters decreased significantly in the visual block condition (p<0.01) while there was no significant difference for single limb support. However, double limb support increased significantly in the visual block system (p<0.01). Conclusions: Therefore, blocking of visual information with muscle fatigue of the ankle joint can affect gait and balance ability of young adults and increase the risk of falls.

A study on the Development of a Driving Simulator for Reappearance of Vehicle Motion (I) (차량 주행 감각 재현을 위한 운전 시뮬레이터 개발에 관한 연구 (I))

  • Park, Min-Kyu;Lee, Min-Cheol;Son, Kwon;Yoo, Wan-Suk;Han, Myung-Chul;Lee, Jang-Myung
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.6
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    • pp.90-99
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    • 1999
  • A vehicle driving simulator is a virtual reality device which a human being feels as if the one drives a vehicle actually. The driving simulator is used effectively for studying interaction of a driver-vehicle and developing vehicle system of a new concept. The driving simulator consists of a vehicle motion bed system, motion controller, visual and audio system, vehicle dynamic analysis system, cockpit system, and etc. In it is paper, the main procedures to develop the driving simulator are classified by five parts. First, a motion bed system and a motion controller, which can track a reference trajectory, are developed. Secondly, a performance evaluation of the motion bed system for the driving simulator is carried out using LVDTs and accelerometers. Thirdly, a washout algorithm to realize a motion of an actual vehicle in the driving simulator is developed. The algorithm changes the motion space of a vehicle into the workspace of the driving simulator. Fourthly, a visual and audio system for feeling higher realization is developed. Finally, an integration system to communicate and monitor between sub systems is developed.

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A Model to Determine the Visual Preference for the Color of Benches Located in Urban Parks (도시공원 벤치색상의 시각적 선호 결정 모형)

  • 유상완
    • Archives of design research
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    • v.14 no.2
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    • pp.137-146
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    • 2001
  • In this paper it is investigated that the visual elements of preference which influence the visual preference for bench. "What color of bench is preferred when the location is the same\ulcorner" Started from those questions, the elements of preference which influence the visual preference for bench is investigated. In this research, a equal standard mark system is applied for the evaluation of visual elements of preference and then the relationship between the visual preference and the elements of preference are examined by the method of multiple regression analysis. The result of primary factor analysis from the visual evaluation in this paper will affect visual preference of the bench in urban park. Thus, the result of this study will contribute to development of urban parks for the maximum satisfaction of park visitors supplying necessary information for a resting place planning and design. It will provide a useful management guide of urban park facilities to prepare a strategic management plan of the benches from the users point of view. Especially, to know the correct preference of people, which will be provided by the evaluation of visual preference to bench will be the key to rest place planning.

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Stereo Image Quality Assessment Using Visual Attention and Distortion Predictors

  • Hwang, Jae-Jeong;Wu, Hong Ren
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.5 no.9
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    • pp.1613-1631
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    • 2011
  • Several metrics have been reported in the literature to assess stereo image quality, mostly based on visual attention or human visual sensitivity based distortion prediction with the help of disparity information, which do not consider the combined aspects of human visual processing. In this paper, visual attention and depth assisted stereo image quality assessment model (VAD-SIQAM) is devised that consists of three main components, i.e., stereo attention predictor (SAP), depth variation (DV), and stereo distortion predictor (SDP). Visual attention is modeled based on entropy and inverse contrast to detect regions or objects of interest/attention. Depth variation is fused into the attention probability to account for the amount of changed depth in distorted stereo images. Finally, the stereo distortion predictor is designed by integrating distortion probability, which is based on low-level human visual system (HVS), responses into actual attention probabilities. The results show that regions of attention are detected among the visually significant distortions in the stereo image pair. Drawbacks of human visual sensitivity based picture quality metrics are alleviated by integrating visual attention and depth information. We also show that positive correlation with ground-truth attention and depth maps are increased by up to 0.949 and 0.936 in terms of the Pearson and the Spearman correlation coefficients, respectively.

The Effects of Temporary Visual Block on the Foot Pressure and Foot Area of Chronic Stroke Patients (일시적인 시각차단이 만성 뇌졸중 환자의 지면 족저압 분포와 족부면적에 미치는 영향)

  • Jeong, Seong-Hwa;Koo, Hyun-Mo
    • PNF and Movement
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    • v.17 no.1
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    • pp.103-109
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    • 2019
  • Purpose: The purpose of this study was to investigate the effect of temporary visual block existence and nonexistence on the change in foot pressure and foot area in stroke patients. Methods: Sixty-one chronic stroke patients volunteered to participate in the study. Foot pressure and foot area were measured using the Biorescue system. The subject maintain a comfortable standing position on the pressure-measuring plate one meter away from the computer. The sequence of the visual variation data while standing on the measuring plate was collected randomly. The data were collected with three repetitions and used the five-second measuring values except the first second and the last second according to each visual condition. All data were analyzed using SPSS version 21.0. The significance level for the statistical inspection was set as 0.05. Results: The comparison between the visual existence and nonexistence status showed statistically significant effects on foot pressure and foot area. The visual nonexistence status showed more improvement in foot pressure symmetry and area than visual existence status. Conclusion: This study shows that the foot pressure and foot area for the chronic stroke patients changed according to the visual states. It is predicted that these data will be used in rehabilitation training programs and to present temporary changes in visual status for stroke patients.

The Effect of Visual Feedback Bicycle Training on Maximal Oxygen Uptake, Quadriceps Muscle Strength, and Running Performance in Healthy Young Adults

  • Kim, Hyeonguk;Lee, Seungwon;Choi, Wonjae
    • Physical Therapy Rehabilitation Science
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    • v.11 no.1
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    • pp.58-65
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    • 2022
  • Objective: The purpose of this study was to investigate the effect of visual feedback bicycle training on running performance, maximal oxygen uptake and quadriceps muscle strength. Design: A randomized controlled trial. Methods: Fifteen healthy adult men with no musculoskeletal or nervous system disease and capable of bicycle training were included. After the pretest, subjects were randomly assigned to visual feedback bicycle training group and general fixed bicycle training group. Both groups were trained two times a week for three weeks, each week for a fixed time and number of repetitions, followed by a six week washout period and then crossing the training method. visual feedback bicycle training provides visual feedback of heart rate in real time using a monitor and a heart rate meter during bicycle training, and general fixed bicycle training performed general bicycle training without visual feedback. After training, each item was measured using a wearable technology, gas analyzer, isokinetic equipment. Results: The results of this study was significant differences in running performance, maximal oxygen uptake and quadriceps muscle strength in visual feedback bicycle training group (p<0.05). The differential effect was found between visual feedback bicycle training group and general fixed bicycle training group in running performance, maximal oxygen uptake, and quadriceps muscle strength (p<0.05). Conclusions: This study suggested that that visual feedback bicycle training can be applied as a useful training method to improve running performance, maximal oxygen uptake and quadriceps muscle strength.

A Basic Study on Development of Web-based Visual Perception Test Program Prototype (웹 기반 시 지각 진단 프로그램의 모형 개발을 위한 기초연구)

  • Ahn, Seong-Hye
    • Archives of design research
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    • v.19 no.2 s.64
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    • pp.5-14
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    • 2006
  • Visual perception is ability that analyze visual information about things accepting through eyes in central nervous system. That is, it is ability that recognize and discriminates a visual stimulus, and analyzes by combining such stimulus with previous experience. At today, work which clears visual perception obstacle's cause through visual perception test and grasps all special quality of visual perception obstacle's is used method of treating that improve visual perception obstacle by visual perception training program. Present, visual perception test tools using the paper and pens are used mainly on psychological consultation of welfare facilities and education for the handicapped or occupational therapy, but a lot of problems are discovered in it. Therefore, purpose of this paper is to develop prototype of web-based visual perception test program that can construct to database to solve existing problem, and to design graphic item. As a result, classified measurement pattern that can diagnose visual perception by three, and illustrated development direction of graphic item for examination with this. Also, extracted check list item that should consider for design and construction of visual perception test program and the variable for feasibility study of believability, and presented process for prototype development.

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Design and Implementation of the On-line Aptitude Test System for People with Visual Impairment (시각 장애인용 온라인 적성검사 시스템의 설계 및 구현)

  • Ban, Chae-Hoon;Park, Hye-Jeon
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.13 no.6
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    • pp.1105-1110
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    • 2009
  • Vocational rehabilitation is defined as a process which helps people with disabilities to maintain life of non-disabled people and vocational assessment is a part of it. Traditionally, vocational assessment is performed through using of assessment tools, vocational counseling and so on. It is very efficient to apply vocational assessment to people with disabilities using the internet, but we should provide them with web accessibility. In this paper, we design and implement the aptitude test system for people with visual impairment supporting web accessibility. We develop the aptitude test system using the Holland Test which is the assessment tool of career guidance and counseling. We also show that the aptitude test system for people with visual impairment supports web accessibility more than previous Holland Test which is served in the internet.

Depth Extraction of Convergent-Looking Stereo Images Based on the Human Visual System (인간시각체계에 기초한 교차시각 스테레오 영상의 깊이 추출)

  • 이적식
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.27 no.4A
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    • pp.371-382
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    • 2002
  • A camera model with optical axes parallel has been widely used for stereo vision applications. A pair of input ages are obtained from a convergent-looking stereo camera model based on the human visual system in this per, and each image is divided into quadrant regions with respect to the fixation point. The reasoning of quadrant partitions is based on the human visual system and is proven by a geometrical method. Image patches : constructed from the right and left stereo images. A modified cepstrum filter is applied to the patches and disparity vectors are determined by peak detection algorithm. The three-dimensional information for synthetic ages is obtained from the measured disparity and the convergent stereo camera model. It is shown that the experimental results of the proposed method for various stereo images are accurate around the fixation point like the human visual system.

Digital Watermarking of JPEG Image Based on Human Visual System (인간 시각 시스템에 기반 한 JPEG 영상의 디지털 워터마킹)

  • Bae, Sung-Ho
    • The KIPS Transactions:PartB
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    • v.11B no.2
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    • pp.125-132
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    • 2004
  • In this paper, a watermark inserting method according to the sensitivity of human visual system and minimizing distortion of original DCT coefficients in DCT transform domain is proposed. The proposed method inserts a more robust watermark in the insensitive block of human vision by reordering the blocks according to the human visual system which is appropriate to the JPEG image compression. It also enhances the invisibility and robustness in high compression rate in terms of the watermark inserting method within the block which minimizes distortions of original DCT coefficients. The computer simulation results show that the proposed method maintains high image quality and good robustness in high compression rate compared with conventional watermarking method.