• 제어로봇시스템학회:학술대회논문집
• /
• 2003.10a
• /
• pp.778-782
• /
• 2003

This paper presents how it is effective to use many features for improving the speed and the accuracy of the visual servo systems. Some rank conditions which relate the image Jacobian and the control performance are derived. It is also proven that the accuracy is improved by increasing the number of features. Effectiveness of the redundant features is evaluated by the smallest singular value of the image Jacobian which is closely related to the accuracy with respect to the world coordinate system. Usefulness of the redundant features is verified by the real time experiments on a Dual-Arm Robot manipulator made in Samsung Electronic Co. Ltd.

• Journal of the Korean Society for Railway
• /
• v.8 no.4
• /
• pp.330-336
• /
• 2005

This paper presents a development of the control and the virtual reality visual system for a tilting train simulator. The user of the tilting train simulator is able to set up the environmental and operating conditions through the user interface provided by the control system. In the control system, an arbitrary track which has user-defined curve radius, length and direction can be generated. The virtual reality visual system provides an artificial environment that is composed of several facilities such as station, platform, track, bridge, tunnel and signaling system. In order to maximize the reality, all of the 3D modeling were based on the real photographs taken in the Jungang line. A dome screen with 1600mm diameter was used to maximize the view angle. The hemispherical screen can ensure the view angle of the 170 degrees of vertical direction and 135 degrees of lateral direction.

• Journal of Mechanical Science and Technology
• /
• v.16 no.6
• /
• pp.762-769
• /
• 2002

This paper presents how effective it is to use many features for improving the speed and accuracy of visual servo systems. Some rank conditions which relate the image Jacobian to the control performance are derived. The focus is to describe that the accuracy of the camera position control in the world coordinate system is increased by utilizing redundant features in this paper. It is also proven that the accuracy is improved by increasing the number of features involved. Effectiveness of the redundant features is evaluated by the smallest singular value of the image Jacobian which is closely related to the accuracy with respect to the world coordinate system. Usefulness of the redundant features is verified by the real time experiments on a Dual-Arm robot manipulator made by Samsung Electronic Co. Ltd..

• Journal of Institute of Control, Robotics and Systems
• /
• v.14 no.4
• /
• pp.369-375
• /
• 2008

The kinematics and control problem of a visual alignment system is investigated, which plays a crucial role in the fabrication process of flat panel displays. The first solution is the inverse kinematics of a 4PPR parallel alignment mechanism. It determines the driving distance of each joint to compensate the misalignment between mask and panel. Second, an efficient vision algorithm for fast alignment mark recognition is suggested, where by extracting essential feature points to represent the geometry of a mark, the geometric template matching enables much faster object recognition comparing with the general template matching. Finally, the overall visual alignment process including the kinematic solution, vision algorithm, and joint control is implemented and experimental results are given.

• Journal of the Korean Academy of Clinical Electrophysiology
• /
• v.3 no.1
• /
• pp.71-84
• /
• 2005

This study had performed with purposes to analyze the influence of the change of vestibular sens, visual and proprioceptive sense to the postural sway, so as to supply the necessary clinical materials through developing the physical therapeutic interventions and assessment format for the diabetic neuropathy patients. The sample consisted of fifteen diabetic neuropathy patients with sensory disorder in their lower limbs and fifteen age-matched normal control group. Then the effect of the GVS and the visual cue open and closed to the postural sway were measured by CoP. The summary of the comparison results were obtained below. In the comparison of diabetes neuropathy patients group and age matched normal control group, however diabetes neuropathy patients group had a decrease in superficial tactile sense(p<.001) and nerve conduction velocity(p<.001), they were able to control the posture and walk. So it is, diabetes neuropaty patients had more disturbance compared with AMC group on at a hard surface, particularly in the visual cue open(p<.001) and visual cue closed(p<.01). Moreover, since diabetes neuropathy patients group had more differences in visual cue open and closed(p<. 01), GVS(p<.01), it meant that they're affected largely by vestibular sense, visual sense. In addition, since there're the largest change in doubled sense disturbance such as visual cue open and closed under GVS, it meant that compensation of other senses were quite important for the diabetes neuropathy patients' postural control. In the conclusion, diabetes neuropathy patients who decrease or lose the somatosensory system, sensory training of visual and vestibular system are likely to be quite essential to control the posture and balance.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
• /
• 1999.03a
• /
• pp.237-242
• /
• 1999

The nature of the interactions between the vestibular and autonomic systems is complex and has not been fully defined. Vestibuloocular reflex induced by sinusoidal rotation and activity of the autonomic nerves in the heart were measured to investigate the interactions between the vestibular system and the autonomic nervous system in healthy adults. Eye movement induced by sinusoidal rotation of the whole body or optokinetic stimulation at 0.04 Hz was analyzed in gain, phase, and symmetry. EKG was measured during vestibular stimulation and analyzed in heart rate variability including mean R-R interval, standard deviation (SD) and coefficient of variance (CV) of R-R interval, and power spectrum of low frequency region (LF) and high frequency region (HF). Gain of eye movement was 0.65${\pm}$0.03 by ratatory stimulation, 0.70${\pm}$0.02 in optokinetic stimulation, 0.08${\pm}$0.02 in visual suppression, and 0.84${\pm}$0.04 in visual enhancement. In R-R interval, resting condition (control) was 0.82${\pm}$0.03 sec, and visual suppression showed significant increase and visual enhancement did significant decrease compared with control (p<0.01).CV was 0.06${\pm}$0.02 in control and visual enhancement increased significantly (p<0.05). In LF/HF control was 1.40${\pm}$0.23, which was not different from rotatory or optokinetic stimulation. But visual suppression decreased LF/HF significantly and visual enhancement increased significantly compared with control (p<0.01). These results suggest that degree of gain corresponds with LF/HF and increased gain in visual enhancement is deeply related to the activity of sympathetic nerves.

• PNF and Movement
• /
• v.15 no.2
• /
• pp.201-208
• /
• 2017

Purpose: The purpose of this study is to determine the effects of visual biofeedback training on the recovery of balance function in stroke patients. Methods: A total of 30 patients with stroke were chosen as the subjects of this study. The subjects were randomly divided into either the visual biofeedback balance training group (experimental group; n=15) or the general balance training group (control group; n=15). The visual biofeedback balance training and general balance training were implemented for 30 minutes a day, three times a week, for a total of four weeks. The subjects' balance ability was measured before and after the interventions. Results: The shift length and surface area of the center of the body decreased in both the experimental group and the control group, with the difference being statistically significant. The shift length and surface area of the center of the body both decreased more in the experimental group than in the control group, and there was a statistically significant between-group difference. Conclusion: The experimental group showed a greater improvement in terms of the balance ability of patients with stroke than the control group. Therefore, we believe that visual biofeedback balance training can be effectively applied for the improvement of balance ability in patients with stroke.

• Research in Community and Public Health Nursing
• /
• v.12 no.2
• /
• pp.397-405
• /
• 2001

The vision disturbances of school- age children has been recognized as and important school health problem. As the visual disturbances of the school-age children is recognized as the nation's health problem. the importance of the development of educational program for visual health should be emphasized. Recently, eyeball movement and other visual health management method has been introduced for prevention or recovery of decrease in visual acuity. But, the effect of eyeball movement was not confirmed yet. And, the controversy around the treatment effect is continued. The decrease of visual acuity is one of the important school health problem as well as it causes discomfort in daily life of the students. So, it should be considered as an important subject for school health and there is a need to develop an effective intervention program for visual health. The purpose of this study is to develop and evaluate the program with the recognition of the need of the intervention for visual health. The visual health promotion program was developed by the researcher and the program was initiated by the school. Nonequivalent control group pretest-posttest design was applied for study which examined the effect of the visual health promotion program. The subjects were 742 children (experimental group: 398; control group: 344). The experiment was composed of health education and eyeball movement. Health education was provided 5 times to the children in the class room. Children of experimental group exercised eyeball movement in the class, watching video for 10 minutes two times a day. The exercise was continued for 10 weeks. The result of the study were as follows. 1) change of visual acuity Before the intervention, mean of the visual acuity was .86 for the experimental group and .91 for control group. After the intervention, mean of visual acuity was .95 for the experimental group and. 90 for the control group. There was no significant difference in the change of visual acuity between experimental and control group. 2) change of refraction. In the experimental group, 327 eyes (41.08%) were normal vision and 469 eyes (58.98%) were eyes of refraction errors, 38.82 % of the total eyes were myopia. There was no significant change in the refraction in the children with myopia after the intervention. 3) Awareness of visual acuity, change of knowledge, behavior. and attitude (1) After the intervention, there was a significant difference in the awareness of visual acuity (experimental group: 70.10%. control group: 50.97%, p<.01). (2) After the intervention, there was a significant knowledge increase in the experimental group (pp<.01). (3) There was no significant difference in the visual health behavior after the intervention. (4) There was a significant positive change in the attitude related to visual health in the experimental group ( pp<.05). 4) There was a significant positive change in the subjective discomfort of the students. But, there was no significant change in the objective eye symptom after the intervention. Even though there was no effect in the visual acuity and the change of the refraction. subjective visual health as well as the attitude and knowledge' of the children and parents toward visual health was improved significantly. Also, there was an increase in the intention of change and the awareness for the visual health management. It is suggested that various educational strategies for visual health promotion should be developed and examined for the visual health promotion of the students.

• Journal of Korean Medicine Rehabilitation
• /
• v.21 no.1
• /
• pp.137-148
• /
• 2011

Objectives : This study was to investigate the visual bio-feedback training for 5 weeks on balance and postural control for patients with stroke. Methods : The 26 subjects were randomly selected from the patients of the E hospital in the S city who met the study conditions. They were divided into a visual bio-feedback training group of 13 patients and a self-resistance exercise group of 13 patients. The visual bio-feedback training group received visual bio-feedback and general physiotherapy for five weeks and the self-resistance exercise group received cycling and general physiotherapy for the same period. The subjects were measured and compared for stability index, weight distribution index, fall down index, functional reach test and timed up and go test before and after the program. Results : The visual bio-feedback training group showed significant changes after the experiment in stability index, weight distribution index, functional reach test and timed up and go test(p<0.05), and the self-resistance exercise group also showed significant differences(p<0.05). The changes between prior to and after the experiment show that the visual bio-feedback training group had more significant effects than the self-resistance exercise group(p<0.05). Conclusions : The visual bio-feedback training for five weeks had effects in the improvement of the balance and posture control of stroke patients. Based on these results, more effective training programs should be developed and propagated.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2004.04a
• /
• pp.235-240
• /
• 2004

The equipment of industrial robot in manufacturing and assembly lines has rapidly increased. In order to achieve high productivity and flexibility, it becomes very important to develop the visual feedback control system with Off-Line Programming System(OLPS). We can save much efforts and time in adjusting robots to newly defined workcells by using OLPS. A proposed visual calibration scheme is based on position-based visual feedback. The calibration program firstly generates predicted images of objects in an assumed end-effector position. The process to generate predicted images consists of projection to screen-coordinates, visible range test and construction of simple silhouette figures. Then camera images acquired are compared with predicted ones for updating position and orientation data. Computation of error is very simple because the scheme is based on perspective projection which can be also expanded to experimental results. Computation time can be extremely reduced because the proposed method does not require the precise calculation of tree-dimensional object data and image Jacobian.