• Journal of information and communication convergence engineering
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• v.19 no.4
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• pp.276-283
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• 2021

In this paper, we propose an effective noise reduction method for photon counting imaging using a discrete wavelet transform. Conventional 2D photon counting imaging was used to visualize the object under dark conditions using statistical methods, such as the Poisson random process. The photons in the scene were estimated using a statistical method. However, photons which disturb the visualization and decrease the image quality may occur in the background where there is no object. Although median filters are used to reduce the noise, the noise in the scene remains. To remove the noise effectively, our proposed method uses the discrete wavelet transform, which removes the noise in the scene using a specific thresholding method that utilizes photon counting imaging characteristics. We conducted an optical experiment to demonstrate the denoising performance of the proposed method.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.4
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• pp.413-428
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• 2013

Purpose: The purpose of this study was to evaluate students and optometrist opinion of the usefulness of different subjects of optometry curriculum.This date will then be used as base-line data during a process of curriculum development Methods: 292 of ophthalmic optic's students and 123 of optometrists were surveyed in the usefulness of curriculum (five-point scale) followed by statistical analysis of the results. Results: Optometrists gave a higher average score for curriculum usefulness (3.89) than the students (3.71). The subject which showed the highest usefulness for the student was optometry (4.55) but clinical practice was the highest for the optometrist (4.48). There was significant differences (p<.05) on optics, ophthalmology, basic science, optometrist related subject and foreign language but optometry and contact lenses showed high usefulness in common without significant difference. The usefulness of subject for the student showed significant difference according to gender, grade, age, and desired working place and has demonstrated significant difference depend on gender, age, scholarship, total working experience as an optometrist, workplace, and position for optometrists as well. Conclusions: It is necessary to continue research for the development of standard and bench-marked curriculum for ophthalmic optics and also the curriculum, which reflecting the usefulness and needs obtained from ophthalmic optics' students and optometrists need to be developed.

• Journal of Korean Ophthalmic Optics Society
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• v.16 no.2
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• pp.117-122
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• 2011

Purpose: This study analyzed the factors related to adaptation of people who wears progressive lenses glasses for the first time. Methods: 463 presbyopia (Aged 41~78) without any ocular diseases with the progressive lens glasses were prescribed from 2010 to 2011 at B clinic in the Gwangju city. Progressive lenses adaptation were analyzed according to gender, age, distance refractive state, presbyopic addition, progressive lens design, the old glasses, astigmatism type, and anisometropia etc. High, mid and low-adapted groups were categorized as the status of wearing progressive lenses glasses, re-wearing, occasionally wearing and failed to weraing, respectively. Results: Men showed significantly higher adaptation (p=0.02) than women. Presbyopic addition (p=0.05) and progressive lens design (p=0.02) were statistically significant. However, it was found that there was so statistical significance for the factors of age, distance refractive state, the old glasses, astigmatism type, and anisometropia. Conclusions: According to the results of this study, when progressive lenses were prescribed, we should consider for adaptation gender, presbyopic addition, and progressive lens design etc.

• Journal of Korean Ophthalmic Optics Society
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• v.12 no.4
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• pp.119-125
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• 2007

The aim of the present study was to compare the contrast sensitivity of soft contact lens wearers, spectacle wearers or emmetropia. Seventy myopic eyes and thirty emmetropic eyes aged 19 to 26 years were collected. The myopic group included 48 eyes corrected with spectacle lenses and 22 eyes of them corrected with contact lenses, too: all had corrected vision acuity of 20/20 or better. Spatial contrast sensitivity was measured using the OPTEC 6500 contrast sensitivity view-in tester included the EyeView　 Functional Vision Analysis software at photopic or mesoopic condition. There was no significant difference in contrast sensitivity between spectacle lenses and emmetropes. Myopes corrected with soft contact lenses showed statistical sensitivity losses at 1.5, 12 cycle/degree spatial frequencies. In conclusion, our findings suggest that loss of contrast sensitivity in soft contact lens wearers might be interpreted as evidence for corneal disruption before corneal pathological events occur in contact lens wearers. Contrast sensitivity testing appears to be a useful method for evaluating soft contact lenses.

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.4
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• pp.335-343
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• 2012

Purpose: In this study, we investigated effects of employees characteristics, expertise, customer satisfaction, devotion of employees to their company, business performance of the optician. Methods: For two months, from August to October 2011, employees participated in individual questionnaires. And the SPSS v14.0 was applied for statistical analysis. Results: This study has shown that the employees characteristics have an effect on the financial performance and satisfaction performance of opticians. In particular, the 'Customers satisfaction' a was important characteristics of employees affecting finance performance, and the 'Devotion to their company' was important factor that affects satisfaction performance. Conclusions: From the result found in this study, it is recommended that further efforts for inspiring the employees devotion to their company and for improving customer satisfaction are required. Above all, employer should pay attention on more suitable ways to encourage work of his employee with considering different situation or circumstance of each optician.

• Journal of the Korean Physical Society
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• v.73 no.12
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• pp.1821-1826
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• 2018

Uniformity is a key feature of state-of-the-art infrared focal planed array (IRFPA) and infrared imaging system. Unlike traditional infrared telescope facility, a ground-based infrared radiant characteristics measurement system with an IRFPA not only provides a series of high signal-to-noise ratio (SNR) infrared image but also ensures the validity of radiant measurement data. Normally, a long integration time tends to produce a high SNR infrared image for infrared radiant characteristics radiometry system. In view of the variability of and uncertainty in the measured target's energy, the operation of switching the integration time and attenuators usually guarantees the guality of the infrared radiation measurement data obtainted during the infrared radiant characteristics radiometry process. Non-uniformity correction (NUC) coefficients in a given integration time are often applied to a specified integration time. If the integration time is switched, the SNR for the infrared imaging will degenerate rapidly. Considering the effect of the SNR for the infrared image and the infrared radiant characteristics radiometry above, we propose a-wide-dynamic-range NUC algorithm. In addition, this essasy derives and establishes the mathematical modal of the algorithm in detail. Then, we conduct verification experiments by using a ground-based MWIR(Mid-wave Infared) radiant characteristics radiometry system with an Ø400 mm aperture. The experimental results obtained using the proposed algorithm and the traditional algorithm for different integration time are compared. The statistical data shows that the average non-uniformity for the proposed algorithm decreased from 0.77% to 0.21% at 2.5 ms and from 1.33% to 0.26% at 5.5 ms. The testing results demonstrate that the usage of suggested algorithm can improve infrared imaging quality and radiation measurement accuracy.

• Journal of Korean Ophthalmic Optics Society
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• v.15 no.3
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• pp.281-286
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• 2010

Purpose: This research provided basic data for refraction by comparing the corrected diopter of trial lens and phoropter. Methods: We compared the corrected diopter of trial lens and phoropter, and analyzed statistical significance and relations of the spherical lens corrected diopter and cylindrical lens corrected diopter according to the types (trial lens and phoropter) of subjective refractive instruments. Also we analyzed statistical significance and relations between cylindrical lens corrected diopter at the astigmatism and the types (trial lens and phoropter) of subjective refractory instruments. Results: When we measured the corrected diopter of simple myopia, the mean value for corrected diopter was S-2.74D using the trial lens and S-2.65D using the phoropter. So the corrected diopter was 0.09D smaller when measured by phoropter. The degree of astigmatism was measured C-0.81D using the trial lens and C-0.77D using the phoropter which showed that the measured value was 0.04D smaller using the phoropter. On correlation analysis between the refractive instruments (trial lens and phoropter) and the corrected diopter, there was significant (p<0.01) strong correlation between refractory machine and corrected spherical diopter (r=0.996) and the correlation between refractory machine and corrected cylindrical diopter was r=0.986 and was also significant (p<0.01). Conclusions: The use of phoropter than trial lens was more desirable when performing refraction on high myopia (simple refractive error, high astigmatism), and when using trial lens, you should consider the vertex distance and the gap between overlapped lenses before prescription.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.2
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• pp.93-104
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• 2015

Purpose: This study aimed to analyze the research trends of Ophthalmic Optic by targeting the papers published in the Journal of Korean Ophthalmic Optics Society and serve it as a basis for future researches. Methods: This study was conducted through a statistical analysis of the general characteristics, researcher characteristics, research characteristics and the research trends from total 990 papers, from the first issue to the last issue in 2014, published in the Journal of Korean Ophthalmic Optics Society. Results: Most common number of the authors of the published papers were two or three, respectively 26.8%. Most of the lead authors belong to the schools in Jeolla-do province (31.3%). Most of the educational system of which lead authors belong to is four-year-course system (43.0%). Most common research methods were optometric tests (40.9%). The most common subjects of researches are about the field of optometry (29.8%). The study shows that there were significant differences in the research methods depending on the school systems of the universities to which the lead authors belong (p=0.000). There also were significant differences in the school systems of the universities to which the lead authors belong, and research methods depending on the research subjects (p=0.000). There were meaningful differences according to the period divisions (1996 to 2004 and 2005 to 2014), i.e. the number of authors has been growing, and it is the same case for the number of the authors who belong to four-year-course universities (p=0.000). The number of papers on optometry and contact lenses have increase. The benefits of the research funds have also increased (p<0.005). In addition, the number of the lead authors in the Seoul and Chungcheong province have increased (p=0.000). Conclusions: For the development of the Ophthalmic Optics, it is necessary to broaden the stratum of researchers and deal with various research topics, And joint efforts between eyewear industry and academia and international cooperations are needed.

• Journal of the Korean Physical Society
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• v.73 no.10
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• pp.1506-1511
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• 2018

Spectral behaviors of lasing from semiconductor square ring microcavities with structures for unidirectional laser oscillation were investigated. When a tapered structure was introduced, the lasing envelope shifted to a shorter wavelength region. Statistical estimate of the additional loss caused by the tapered structure was carried out by analyzing spectral data from many sets of cavities with various sizes. When a saw-edged structure was introduced, the unidirectional lasing functioned well but no apparent spectral shift was observed due to negligible additional loss.

• Journal of Korean Ophthalmic Optics Society
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• v.15 no.1
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• pp.73-78
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• 2010

Purpose: The purpose of this study was to examine diurnal variation of accommodation on people whose age are between 35 and 50 years old with frequent alternation of accommodation at period 1 (8:00-10:00), period 2(13:00-15:00) and period 3 (18:00-20:00). Methods: All \04 subjects were separated to nonpresbyopia and incipient presbyopia. Tests were done for amplitude of accommodation, accommodative facility and relative amplitude of accommodation. Results: Both nonpresbyopia and incipient presbyopia had the highest amplitude of accommodation in oculus dexter, oculus sinister and oculus uterque at period 2. In addition, the incipient presbyopia showed the statistical significance of daily change. The nonpresbyopia had the most accommodative facility at period 3 and incipient presbyopia had the most accommodative facility at period 2. Their daily variations were statistically significant. Both nonpresbyopia and incipient presbyopia had the most negative relative accommodation of daily change at period I. Both of them had the most positive relative accommodation at period 2. Conclusions: The incipient presbyopia had the highest amplitude of accommodation, accommodative facility. and positive relative accommodation (except the negative relative accommodation) at period 2.