• Journal of Korean Ophthalmic Optics Society
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• v.16 no.3
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• pp.247-253
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• 2011

Purpose: The changes in properties of plastic lens due to heating was investigated. Methods: Plastic lenses of -2.00 diopter were heated at 60-100$^{\circ}C$, and then changes of refractive power, surface condition and transmittance were examined. Results: It was shown that the changes of lens surface due to heating happened at 70$^{\circ}C$ for 1h, 75$^{\circ}C$ for 10 min and 100$^{\circ}C$ 10 sec, respectively. More serious crack was occurred in high index lens and at higher heating temperature, respectively, and transmittance decreased depending on the extent of the damage on the surface of lens. Conclusions: Heating at temperatures above 70$^{\circ}C$ drives cracks on the surface of lens. Optician should recommend an appropriate lens considering the wearer's working conditions and guide for paying attention when they use eyeglasses.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2000.08a
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• pp.293-296
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• 2000

본 논문에서는 얼굴의 구조적 특성과 누적 히스토그램을 이용하여 다양한 정보를 포함하고 있는 얼굴의 6가지 표정을 인식하는 알고리즘을 기술하였다. 표정 인식을 위해 특징점 추출 전처리 과정으로 입력 영상으로부터 에지 추출, 이진화, 잡음 제거, 모폴로지 기법을 이용한 팽창, 레이블링 순으로 적용한다. 본 논문은 레이블 영역의 크기를 이용해 1차 특징점 영역을 추출하고 가로방향의 누적 히스토그램 값과 대칭성의 구조적인 관계를 이용하여 2차 특징점 추출 과정을 거쳐 정확하게 눈과 입을 찾아낸다. 또한 표정 변화를 정량적으로 측정하기 위해 추출된 특징점들의 눈과 입의 크기, 미간 사이의 거리 그리고 눈에서 입까지의 거리 정보를 이용하여 표정을 인식한다. 1, 2차 특징점 추출 과정을 거치므로 추출률이 매우 높고 특징점들의 표정에 따른 변화 거리를 이용하므로 표정 인식률이 높다. 본 논문은 안경 착용 영상과 같이 복잡한 얼굴 영상에서도 표정 인식이 가능하다.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.3
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• pp.311-318
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• 2015

Purpose: This study was designed to investigate the prevalence rate of refractive error with gender and age presenting visual acuity of primary student in Jeonnam. Methods: Subjective refraction, objective refraction and visual acuity test were examined on 735 primary school children who ages of 8~13 years lived in Jenman. Presenting visual acuity test was using Han's visual acuity chart and objective refraction was carried out using auto-refractometer. Results: The presenting visual acuity was 0.1 worse in the eye of 54(7.3%) students and 49(7.3%) of them wearing the glasses. The rate of the wearing glasses were 79.3% in 0.125~0.25 visual acuity, 64.2% in 0.3~0.5 visual acuity and 61.6% in 0.6~0.8 visual acuity. It was appeared that 269(36.6%) of them were emmetropia, 321(43.7%) of them were myopia and 56(7.6%) of them were hyperopia, and 89(12.1%) of them were astigmatism. The prevalence rate of myopia was the highest and followed by the prevalence rate of astigmatism. The low degree of myopia occupied the most and the medium degree of myopia showed the tendency of increase as the students get olds. The prevalence rate of the hyperopia showed the tendency of decrease as the students get olds. The prevalence rate of with the rule astigmatism were 50.6% students and against the rule astigmatism were 48.3% of students. Conclusions: The present study reveals the considerable prevalence rates, 466(63.4%) of included subjects, of refractive errors among primary students in Jeonnam province. The rate of the wearing glasses were 313(42.6%). The prevalence of myopia increases as the students get older. Therefore students of visual management is considered necessary through the visual acuity test and refractive examination.

• Journal of Korean Ophthalmic Optics Society
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• v.12 no.2
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• pp.95-106
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• 2007

The purpose of this study was to investigate effect of spectacle correction therapy instead of occlusion therapy for refractive amblyopia treatment. Spectacle correction were prescribed to give the same effect as a occlusion therapy by under correction for normal eye and there was no additional treatment but only spectacle correction for hyperopic amblyopia. The results can be summarized as follows: 1. In hyperopic amblyopia after correction, initial visual acuity($Mean{\pm}SD$) was $0.36{\pm}0.13$ and final visual acuity($Mean{\pm}SD$) was $0.82{\pm}0.23$. 2. Regardless with age, there was significant differences between initial acuity and final acuity, it shows improvement in visual acuity after spectacle correction treatment. 3. Initial correction age did not influence the length of treatment and success rate of treatment, so that ambyopia correction effect not related with age. 4. Compared with initial visual acuity with final visual acuity, initial visual acuity was in proportion to final visual acuity. 5. Incidence was higher in hyperopia and hyperopic astigmatism than myopia and myopic astigmatism in refractive amblyopia group and the therapy was more effective for hyperopia and hyperopic astigmatism than myopia and myopic astigmatism. 6. Treatment was effective even for children who is older than 8 years.

• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.869-872
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• 2000

본 논문에서는 K-L 변환을 기반으로 한 Fisherface 알고리즘과 Elastic Graph Matching 방법을 사용하여 보다 효율적인 얼굴 인식 방법을 제안하고자 한다. 즉, 얼굴의 모양 정보뿐만 아니라, 영상 픽셀의 그레이 정보를 동시에 이용할 수 있는 Elastic Graph Matching 방법과 통계학적으로 신호의 차원을 줄일 뿐만 아니라 주위 환경의 변화에 강인한 Fisherface 알고리즘을 효율적으로 결합하고자 한다 본 연구에서는 얼굴을 인식하는 데에 있어서 주로 문제가 되는 광원의 위치에 따른 조도의 변화, 얼굴 표정 변화, 안경 착용 여부 등을 고려한 Yale대학 데이터베이스에 대해 기존의 여러 얼굴 인식알고리즘을 실험 및 비교하였다. 또한, 이들을 효율적으로 결합할 수 있는 인식 알고리즘을 제안함으로써 인식률 및 속도 면에서 비교적 만족할 만한 결과를 얻을 수 있었다.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10b
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• pp.458-460
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• 2000

본 논문에서는 유전자 알고리즘(GA)과 Support Vector Machine(SVM)을 결합하여 사용한 얼굴 인식 시스템을 제안한다. 기존의 SVM을 이용한 얼굴 인식 연구에서는 얼굴 전체 영상을 SVM의 입력벡터로 사용하는데 반해, 본 연구에서는 GA를 이용하여 얼굴 영상 중에서 개인별로 식별 능력이 우수한 특징들만을 선택하여 이를 SVM의 입력벡터로 사용한다. 조명, 표정, 안경 착용 등 다양한 변화가 있는 Yale 얼굴 데이터베이스를 사용하여 실험한 결과, 얼굴 전체 영상을 사용한 경우보다 더 좋은 인식률을 보였다. 또한 제안된 방법에 의한 얼굴 인식 시스템은 각 개인별로 식별력이 우수한 특징들만을 저장하므로, 얼굴인식 시스템을 구성하기 위해 저장될 정보의 양이 현저하게 감소하게 된다.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.4
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• pp.25-30
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• 2008

Purpose: In this paper, we have analyzed the problems of the Oh's report which is used to the basic data for supply and demand of medical technicians and studied a proposal for improvement to control system and supply and demand of korean optometrists. Methods: We have analyzed errors of Oh's report including supply and demand for medical technicians and management policy, expecting number for future optician, inaccurate estimation by limited data (employment rate, retirement rate, mortality rate) and an incorrect method of measurement for future supply and demand. Results: Oh's report showed the 18% error for estimation of supply which exclude the irregular entrance students. The estimation of supply was calculated by graduation rate 62.6% (college and University of Technology are 78.9% and 85.98% respectively), employment rate 65.8% (the average employment between 2002 and 2007 is 73.96%) and retirement rate is 2.3% (the retirement of pharmacists is 1.3%) but it showed the significant differences to objective data. For estimate the suitable ratio of optometrists to the population, the ratio use of medical facilities by an age group was used, and suggested spectacle wearers 1,280 persons (populations 2,928 persons) per optometrist but the different from reference of Germany (4,706 persons), America (1,789 persons) and Korea (1,825 persons/an optometrist) are applied to estimation on supply. This report applied the low employment rate and argued that maintain the present situation, but claimed that utilize unemployment persons. The above result has induced double weighting effect on estimation of supply. Conclusions: To solve the related problems of supply and demand, we have to make a search for exact data and optimum application model, have to take an example of nation similar job category as Germany and the research result of the job satisfaction into consideration. After we get the integrated research result, we must carried out the policy with fairness and balance for the estimation of supply and demand. Therefore exact research is required prior to beginning policy establishment, government and related group have to make a clear long-term plan and permanent organization for medical technician to establish supply and demand of medical technician.

• Journal of Korean Ophthalmic Optics Society
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• v.16 no.3
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• pp.229-235
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• 2011

Purpose: The present study was performed to evaluate the safety of ophthalmic lenses in domestic market since eyeglasses wearers could be exposed to the negligent accident by damaged ophthalmic lenses. Method: Totally, 160 ophthalmic lenses (NK55, ${n_{d}}$ = 1.56) with the refractive powers of -3D, -6D, +3D, +6D manufactured by 4 companies in domestic market were evaluated using drop ball test. In accordance with FDA standard, steel ball (~16 g) was freely dropped on these ophthalmic lenses from 127 cm high and the surfaces of lenses were observed. Results: From the study, center thicknesses of NK55 ophthalmic lenses manufactured by 4 different companies showed somewhat different numbers even though the lenses had the same refractive index and powers. All convex lenses of +3D, +6D were evaluated as the safe lenses since there was no damage such as crack and broken found on the lens surfaces after drop ball testing. However, some noticeable broken was shown on the surfaces of concave lenses with relatively thinner center thickness. Especially, 59(73.8%) of total 80 concave lenses with the refractive power of -3D and -6D classified as unacceptable lenses to FDA standard. Conclusions: From the results, the negligent accident by damaged ophthalmic lenses should be considered as well as the correction of visual acuity, design and price when customers purchase eyeglasses. Thus, the enforcement regulation like drop ball testing of uncut ophthalmic lens could be suggested to guarantee the safety of ophthalmic lenses in domestic market.

• Korean Journal of Health Education and Promotion
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• v.10 no.1
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• pp.87-97
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• 1993

The purpose of this study is to give practical information about eyesight care-preventing refractive error and actual conditions of wearing glasses(or contact lenses) to help school health education, For this study, 1,216 freshmen were sampled from liberal and vocational high schools in Seoul and the survey was successfully accomplished. Following are the major findings results of this study: 1. The percentage of the freshmen wearing glasses in girls high school were 57.5 percent in liberal high school and 41.7 percent in vocational high school. 2. The percentage of both the students and parents wearing glasses were 49.9 percent in liberal high school and 33.8 percent in vocational high school. 3. From the survey, the majority of the students began to wear glasses during their middle school years. The percentages were 46.6 percent in liberal high school and 62.1 percent in vocational high school. 4. The percentage of the students who got their glasses prescribed from an ophthalmic clinic were 60.6 percent in liberal high school, 31.5 percent in vocational high school and the rest got their glasses from the optician.. 5. The percentage of the students wearing glasses who didn't have optometry check-up for 6 months were 57.2 percent in liberal high school and 38.4 percent in vocational high school. The percentage of the students not wearing glasses in the same situation were 61.9 percent in liberal high school and 41.5 percent in vocational high school. 6. The percentage of the students who believe that the health education in school is necessary for the prevention of amblyopia were 79.2 percent of strdents attending in liberal high school, 82.9 percent in vocational high school, 81.5 percent of students wearing glasses and 80.8 percent of students not wearing glasses.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2010.11a
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• pp.145-148
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• 2010

본 논문에서는 3차원 스테레오 영상에서의 시각적 피로도와 안구의 운동량과의 상관관계를 도출하고 시각적 피로도 측정 시스템을 제안한다. 제안한 측정 방법은 3차원 스테레오 영상 시청자의 피로도가 누적되었을 때, 안구의 단속성 운동(saccade)이 감소할 것이라는 가정에 기반을 둔다. 액티브 셔터글라스 방식의 3D 안경을 착용한 시청자의 동공을 검출하고 추적하기 위해 적외선 광원 및 적외선 카메라를 이용한다. 획득한 영상에 대해 이진 임계화를 적용하고 타원 피팅을 수행하여 동공의 위치를 검출한다. 피팅된 타원의 이심률과 크기 및 위치를 제한하여 검출 오류를 줄인다. 검출된 동공의 위치를 바탕으로 안구의 단속성 운동량을 측정한다. 실험에는 변이 정도가 크지 않아 편안하게 시청 가능한 스테레오 영상과 과도한 변이를 가져 시청하는데 불편한 영상이 분리되어 사용되었다. 이들 영상에 대해 각각 실험자의 단속성 운동량을 측정하였다. 실험 결과에서 안구의 단속성 운동량이 변이가 큰 영상에서 그렇지 않은 영상에 비해 감소하는 경향이 나타났다.