• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 1999.11a
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• pp.111-114
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• 1999

Off-vertical axis rotator was developed to differentiate each function of the canal and otolith in the vestibular system and evaluate subjective symptoms during postural change. Eye movement induced by various types of rotation was measured in normal subjects. Nystagmus with fast component corresponding to direction of rotation was occurred by sinusoidal earth vertical axis rotation, and the gain of eye movement in vestibuloocular reflex (VOR) was lower than in visual vestibuloocular reflex (VVOR) and higher than in visual fixed vestibuloocular reflex (VFX). Degree of dizziness was proportioned to degree of gain. off-vertical axis rotation was produced severe dizziness than earth vertical axis rotation. These results suggest stimulation of the otolith should be minimized to make a stable and pleasant condition in work and travel.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.10
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• pp.3789-3793
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• 2010

To investigate accuracy of graduated scale of schematic retinoscope training eye(schematic eye) and induced effect when measured at off-axis from visual axis. Two skilled retinoscopist measured refractive power using retinoscope in random order. Seven schematic eyes from a single manufacturer were recruited and set to mark +4.00 to -6 diopter(+4, +3, +2, +1, 0, -1, -2, -3, -4, -5, -6). After introducing +2.00 diopter trial lens(50cm working lens), neutral distance was measured at 180 degree to estimate accuracy of scale, and refractive power measured at 0, 5, 10, 15 and 20 degree off-axis to see if any error was induced. According to the results measured by two specialists, in six of seven schematic eye, scale setting varied (p<0.05) and measured refractive power at 5, 10, 15 and 20 degree off-axis from visual axis were $-0.13{\pm}0.06$, $-0.29{\pm}0.06$, $-0.58{\pm}0.11$, and $-0.83{\pm}0.16$ diopter respectively. In some schematic eye, scale graduated on the schematic eye and scale measured by retinoscopy could be different and if retinoscopy is performed off-axis from visual axis, any measuring error can be caused.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.377-380
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• 2001

The vestibular system located in the inner ear controls reflex body posture and movement. It has the semicircular canals sensing an angular acceleration and the otolith organs sensing a linear acceleration. With this organic signal, medical doctor decide if a person has disease or not. To obtain this data, a precision stimular system is considered. Robust control is needed to obtain eye signals induced by off-vertical axis rotation because of an unbalanced load produced by tilting the axis of the system upto 30 degrees. In this study, off-vertical axis rotatory system with visual stimulation system are developed. This system is consisted of head mounted display for generating horizontal, vertical, and three dimensional stimulus patterns. Furthermore wireless recording system using RF modem is considered for noiseless data transmission.

• The Transactions of the Korean Institute of Power Electronics
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• v.6 no.4
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• pp.325-332
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• 2001

The vestibular system located in the inner ear controls reflex body posture and movement, It has the semicircular canals sensing an angular acceleration and the otolith organs sensing a linear acceleration. With this organic signal, medical doctor decide if a person has disease or not. To obtain this data, a precision stimular system is considered. Robust control is needed to obtain eye signals induced by off-vertical axis rotation because of an unbalanced load produced by tilting the axis of the system upto 30 degrees. In this study, off-vertical axis rotatory system with visual stimulation system are developed. This system is consisted of head mounted display for generating horizontal, vertical, and three dimensional stimulus patterns. Furthermore wireless recording system using RF modem is considered for noiseless data transmission. Detailed data was described.

• The Transactions of the Korean Institute of Power Electronics
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• v.7 no.6
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• pp.524-530
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• 2002

A control of the body posture and movement is maintained by the vestibular system, vision, and proprioceptors. Afferent signals from those receptors are transmitted to the vestibular nuclear complex, and the efferent signals from the vestibular nuclear complex control the eye movement and skeletal muscle contract. The postural disturbance caused by loss of the vestibular function results in nausea, vomiting, vertigo and loss of craving for life. The purpose of this study is to develop a off-vertical rotatory system for evaluating the function of semicircular canals and otolith organs, selectively, and visual stimulation system for- stimulation with horizontal, vortical and 3D patterns. The Off-vortical axis rotator is composed of a comportable chair, a DC servo-motor with reducer and a tilting table controlled by PMSM. And a double feedback loop system containing a velocity feedback loop and a position feedback loop is applied to the servo controlled rotatory chair system. Horizontal, vertical, and 3D patterns of the visual stimulation for applying head mounted display are developed. And wireless portable systems for optokinetic stimulation and recording system of the eye movement is also constructed. The gain, phase, and symmetry is obtained from analysis of the eye movement induced by vestibular and visual stimulation. Detailed data were described.

• Journal of the Optical Society of Korea
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• v.16 no.3
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• pp.243-246
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• 2012

An off-axis four-mirror-anastigmatic telescope is presented here which is composed of two aspheric surfaces and two spherical surfaces. The entrance pupil diameter is 290 mm and the stop is located at the primary mirror. The effective focal length is 900 mm. The strip field of view for the telescope is $15^{\circ}{\times}0.2^{\circ}$ and if the telescope is launched into an orbit about 400 km altitude, the observed range width will be more than 105 km within a scene without any other auxiliary scanning instrument. The spectral range can be as wide as from visual wave band to infrared wave band in the mirror system. This telescope can be used for environmental monitoring with different detectors whose pixel is adapted to the optical resolution. In this paper, the spectral range is chosen as 3.0 -5.0 ${\mu}m$, and center distance of the pixel is 30 ${\mu}m$. And the image quality is near the diffraction limit.

• Journal of Korean Ophthalmic Optics Society
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• v.12 no.3
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• pp.83-87
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• 2007

This study was classified and compared astigmatism's refractional abnormal degrees with visual acuity state of full correction which turned on axises of only 5 degree, 10 degree, and 15 degree. Subjects of this study were 57 college students (114 eyes) who had neither eye diseases nor binocular abnormality, were from their twenties to fifties, with myopia. It appeared that 30.8% of subjects who had astigmatism wore glasses with wrong axis of astigmatism. After accurate correction of the visual acuity and degrees of astigmatism, when we moved to corrected axises at 5 degree, 10 degree, 15 degree, failure of visual acuity with one line or more were 56.1%, 84.2%, 93.8%, respectively. When we comapre the completely-corrected visual acuity with the visual acuity with dricted axes, the bigger the width of visual acuity's weakness was the bigger the drifted angle. The change of normal visual acuity according to drifting angle of corrected axises of astigmatism, when we compared with full correction, appeared 0.94 in 5 degree, 0.87 in 10 degree, and 0.79 in 15 degree. Drift of 5 degree from fully corrected axis, corresponded to difference of visual acuity about one line, drift of 10 degree to 1.8 line difference of visual acuity, and drift of 15 degree about to 2.6 line difference. Through this study, we were sure that, in the case of drifting away from the right axis of astigmatism, it lead to visual weakness and asthenopia. Therefore we darely advise that optometrists should make mistake of axis least by confirming accucacy of corrected axis after despensing of spectacles of astigmatism.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.10
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• pp.1311-1316
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• 1999

A visual servoing method has been proposed based on disturbance observer to eliminate the effect of the off-diagonal component of image feature Jacobian, since performance indices such as measurement sensitivity of visual features, sensitivity of the control to noise and controllability could be improved when an image feature Jacobian was given as a block diagonal matrix. In this paper, experimental results of disturbance observer-based visual servoing are discussed where Samsung FARAMAN-AS1 6-axis industrial robot manipulator is employed. Also, the feature saturator is proposed to stabilize the disturbance observer loop by saturating the differential changes of the image features.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.579-582
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• 2002

In acquiring the surface information of a part, two types of measuring machines have been used: contact type and non-contact type. Since each measuring device has the pres and cons, an integrated measuring system is proposed to acquire the optimal point data. In order to implement the integrated measuring system, the relationship of coordinate systems between each measuring device should be established. In this paper, a new datum fixture and a calibration method for the multiple-sensor measuring system are proposed. The datum fixture is designed to interface two machines, a CMM and a laser scanner. The position of the datum fixture is calibrated by the axis information off motorized rotation stage which is used for a part setup.

• Proceedings of the KIEE Conference
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• 1999.07g
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• pp.3077-3079
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• 1999

A visual servoing method has been proposed based on disturbance observer to eliminate the effect of the off-diagonal component of image feature Jacobian, since performance indices such as measurement sensitivity of visual features, sensitivity of the control to noise and controllability could be improved when an image feature Jacobian was given as a block diagonal matrix. In this paper, experimental results of disturbance observer-based visual servoing are discussed where Samsung FARAMAN-ASl 6-axis industrial robot manipulator is employed. Also, the feature saturator is proposed to stabilized the disturbance observer loop by saturating the differential changes of the image features.