• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.21 no.9
• /
• pp.32-38
• /
• 2007

In this study, a new algorithm for measuring the velocity and distance from a camera to a moving object by using pseudo-stereo images obtained from a single camera with a stereo adapter is proposed. The proposed system is similar to a parallel visual stereo system using a two-camera system, but because this system can obtain pseudo-stereo images form a single camera, it has advantages not only in the aspect of cost but also in stereo conformity by arrangement and the calibration of the left and right stereo cameras upon image processing.

• Proceedings of the IEEK Conference
• /
• 2000.11d
• /
• pp.17-20
• /
• 2000

This paper describes a shape-based object recognition algorithm using multiple distance images. For the images containing dense edge points and noise, previous Hausdorff distance (HD) measures yield a high ms error for object position and many false matchings for recognition. Extended version of HD measure considering edge position and orientation simultaneously is proposed for accurate matching. Multiple distance images are used to calculate proposed matching measure efficiently. Results are presented for visual images and infrared images.

• The Bulletin of The Korean Astronomical Society
• /
• v.46 no.2
• /
• pp.80.3-81
• /
• 2021

RR Lyrae variables are excellent distance indicators thanks to their visual magnitude-metallicity relation and well-defined Period-Luminosity Relations (PLRs) at infrared wavelengths. These population II variables together with the tip of the red giant branch provide primary calibration for the first-rung of the population II distance ladder. We will present new empirical calibration of RR Lyrae PLRs at near-infrared wavelengths using our data from the ongoing CFHT-WIRCam RR Lyrae program. We will discuss the systematic uncertainties involved in the calibration of these relations based on the latest Gaia EDR3 parallaxes and the implication for the cosmic distance scale.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.23 no.3
• /
• pp.1-14
• /
• 1995

The aspect of visual accessibility to urban green spaces is an important factor because it contributes making pleasant environment by increasing the visual experience of nature in urban environment. But we have tried neither to consider nor to measure it. Since he concept of visual accessibility has not formally defined yet, it was operationally defined in this study. And then the model of measuring visual accessibility was suggested and verified through the case study on neighborhood parks in Seoul. The findings are as follows : 1) The concept of visual accessibility is defined as opportunity and potentiality to observe green spaces. 2) The model of measuring visual accessibility deals with not only adjacent area but also viewshed area. In adjacent area, considering factors are the area of road adjacent to green spaces and the area of exposed green spaces. In viewshed area, considering factors are the area of road located in viewshed area, the area of exposed green spaces, and the weight according to observing distance. 3) The final model of measuring visual accessibility suggested in this study is as follows.

• Journal of Korean Ophthalmic Optics Society
• /
• v.14 no.2
• /
• pp.1-8
• /
• 2009

Purpose: The purpose of this study is to compare degrees of asthenopia in after wearing of dispensed reading glasses with different criterion of P.D. Methods: The person who has minus near correction power (distance correction value (-)) is compared to the degree of asthenopia by wearing of dispensed reading glasses with near P.D(-B) and distance P.D. The person who has plus near correction power is compared to degree of asthenopia by wearing of dispensed reading glasses with near P.D-B, distance P.D, near P.D-A. The "Near-P.D-A" means reduced optical centre distance of reading glasses of positive correction value at which the same effect of prism B.O through near visual point in distance glasses exist at near visual point in reading glasses. Results: When near correction value is (-), dispensed reading glasses with distance P.D have caused less asthenopia than dispensed glasses with near P.D-B. When the near correction value is (+), we cannot confirm that which P.D is more useful for reading glasses. As a result of this study, dispensed reading glasses with near P.D-A have caused less asthenopia than another criterion of P.D. Conclusion: The effect of prism B.I through a near visual point in distance glasses ((-) correction value) reduce convergence demand. Therefore (-) correction value-reading glasses support convergence in near vision, because the effect of prism B.I of reading glasses is smaller than that of distance glasses. When the near correction value is (+), centration points can be determined by one of near P.D-A, near P.D-B, distance P.D.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2007.06a
• /
• pp.405-406
• /
• 2007

• Journal of Korean Ophthalmic Optics Society
• /
• v.9 no.2
• /
• pp.473-480
• /
• 2004

Recently, they are interested in the relation between night's vehicle accidents of drivers and the dynamic visual acuity at home and aboard. So, in this research, we tried to design an optical system of the inspection equipment to measure the dynamic visual acuity. A optotype standard did to Landolt's ring with 45mm of diameter and 9mm of gap to maintain the visual acuity of 1.0 in the 30m distance. An optical structure of the inspection equipment was composed of the sequence of an observer, a plus refraction lens system, a minus refraction lens system, and an optotype that was arranged to have characteristics that the size of the first virtual image of the optotype made by the minus refraction lens system grows bigger gradually according to the optotype movement to near distance from far distance, and also the first virtual image moves to the principle plane from the focal point of the plus refraction lens system as the size of the first virtual image arranged to the inside of focal distance of plus refraction lens system grows bigger gradually. As doing these processes, we completed the optical system of which characteristic is that the position of the final second virtual image moves to 3m from 50m as the size of the second virtual image made by the plus refraction lens system maintains to be regular.

• Journal of Korean Ophthalmic Optics Society
• /
• v.20 no.3
• /
• pp.325-331
• /
• 2015

Purpose: This study was to find the correlation between exophthalmetry and visual functions. Methods: Exophthalmetry and visual functions of 200 adults without ophthalmophathy and general disease were examined. Exophthalmetry were measured with Hertel's exophthalmometer. Visual functions (myopia, distance exophoria, near exophoria, near point of convergence, near point of accommodation) were measured for three times. Results: The exophthalmetry was $13.59{\pm}1.10mm$. Myopia, distance exophoria, near exophoria, near point convergence, and near point accommodation were measured as $-2.48{\pm}1.91D$, $3.51{\pm}1.78{\Delta}$, $5.73{\pm}2.44{\Delta}$, $9.63{\pm}2.82cm$, and $21.73{\pm}10.28cm$. With increasing exophthalmetry, the unaided visual acuity, myopia and astigmatism were decreased. On the other hand, distance exophoria, distance esophoria, near exophoria, near point of convergence and near point of accommodation were significantly increased, while exophthalmetry was increased. Conclusions: The relationship between visual functions and exophthalmetry were found to be statistically significant. It could be used as the clinical criteria for prescription of binocular inspections.

• Journal of Korean Ophthalmic Optics Society
• /
• v.19 no.1
• /
• pp.105-109
• /
• 2014

Purpose: To compare the change of visual acuity and NIBUT after watching smart-phone in 1 hour under low intensity of illumination. Methods: 50 subjects (male 22, female 28) aged 20's years old ($20.7{\pm}2.4$ years) who do not have eye disease and have a good eye condition were participated for this study. Objective refraction, corrected distance visual acuity and NIBUT were measured before and after watching smart-phone (Galaxy 2, Samsung, KOREA) under low intensity of illumination (0 lx.) Objective refraction was carried out using auto-chart project (CP-1000, Dongyang, Korea), phoropter (VT-20, Dongyang, Korea) and auto refractor-keratometer (MRK-3100, Huvitz, Korea). Results: Refractive error was changed from $-3.20{\pm}2.00$ D to $-3.38{\pm}2.00$ D (p=0.006) and corrected distance visual acuity was changed from $0.93{\pm}0.08$ to $0.91{\pm}0.10$ (p=0.000) and NIBUT was changed from $10.48{\pm}7.00$ seconds to $10.29{\pm}6.47$ seconds (p=0.761) before and after watching smart-phone under low intensity of illumination. Conclusions: Continuous watching smart-phone under low intensity of illumination lead to temporal change of distance visual acuity and suitable rest may reduce the influence of distance visual acuity and tear safety.

• Korean Journal of Cognitive Science
• /
• v.8 no.4
• /
• pp.63-75
• /
• 1997

Changes in visual sensitivity were investigated as a function of distance from the locus of attention. While a subject was fixating at a point on a frontal plane, one of the two attention inducing points placed horizontally and symmetrically 4。 apart from it was blinked and a target immediately followed at a location around the blinking dot. The subject's task was to decide and report whether the target was present or abscent. The rate of detection was the highest at the immediate vicinity of the locus of attention and decreased gradually as a function of the distance from it. Results of the experiments support the gradient model of attention-induced changes in visual sensitivity.