• 한국정보컨버전스학회논문지
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• 제6권2호
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• pp.51-55
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• 2013

가까운 물체를 보기 위해서 조절이 일어난다. 이 조절은 개인마다 다른 특징이 있다. 이론적 조절력과 실제 조절력도 차이가 생긴다. 이를 조절지체라 한다. 조절지체에 직접적인 영향을 미치는 것은 초점심도이다. 초점심도는 동공크기와 굴절력에 영향을 받는다. 동공크기가 작을수록, 굴절력이 높을수록 초점심도가 깊어지게 된다. 초점심도가 깊어짐에 따라 조절지체가 많이 발생하게 된다. 본 논문에서는 굴절력과 조절지체의 관계에 대한 연구를 하였다. 조절지체를 측정하기 위해서 단안평가법을 이용하였다. 단연평가법으로 측정한 결과 조절지체는 굴절력이 증가함에 따라 같이 증가하는 경향을 나타내었다. 전체 조절 지체량은 0.51D로 측정되었다. 남성은 0.52D, 여성은 0.49D로 측정되었다. 성별에 따른 조절지체량도 굴절력이 증가함에 따라 같이 증가하는 경향을 보였다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.39-42
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• 2008

We have developed new display techniques that allow presentation of nearly correct focus cues. Using these techniques, we find that stereo vision is faster and more accurate, and that viewers experience less discomfort, when focus cues are consistent with simulated depth.

• Journal of the Optical Society of Korea
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• 제20권3호
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• pp.407-412
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• 2016

We analyzed through numerical simulations the properties of a square beam homogenizer near the target for laser shock peening. The efficiency was calculated near the target by considering the plasma threshold of the metals. We defined the depth of focus of the square beam homogenizer with a given efficiency near the target. Then, we found the relationship between the depth of focus for the laser shock peening and four main parameters of the square beam homogenizer: the plasma threshold of the metal, the number of lenslets in the array-lens, the focal length of the condenser lens and the input beam size.

• Journal of the Optical Society of Korea
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• 제1권2호
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• pp.90-93
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• 1997

The shallow depth of focus in conventional light microscopy hinders the observation of the whole image when the object is thicker than the depth of field. Most of the existing techniques measured the object distance, which is not necessarily the actual distance of each pixel in the image. We implemented a means of determining the "best focus" of each pixel and located the height of object points by sectioning at different sample heights. Combining the height information and its gray values together, we obtained an image where the blur from the finite depth of focus is eliminated. Limitations of the technique are discussed together with composed images.ed images.

• Current Optics and Photonics
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• 제1권2호
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• pp.125-131
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• 2017

We propose a new graphical method for selecting a pair of optical and housing materials to simultaneously athermalize and achromatize an LWIR optical system. To have a much better opportunity to select the IR glasses and housing materials, an athermal glass map is expanded by introducing the DOE with negative chromatic power. Additionally, from the depth of focus in an LWIR optical system, the tolerable housing boundary is provided to realize an athermal and achromatic system even for not readily available housing material. Thus, we can effectively determine a pair of optical and housing materials by reducing the thermal shift to be less than the depth of focus. By applying this method to design a night vision camera lens, the chromatic and thermal defocuses are reduced to less than the depth of focus, over the specified waveband and temperature ranges.

• 방송공학회논문지
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• 제16권5호
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• pp.883-893
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• 2011

본 논문에서는, 피사계심도가 낮은 카메라로 획득한 영상에서 초점이 맞는 부분과 그렇지 않은 부분을 나누는 새로운 초점 정량화를 설계하고 초점 정량화에 기반한 decision map을 이용하여 획득한 영상과 위너필터링으로 복원한 영상의 정합을 통해 영상의 피사계심도를 확장하였다. 기존의 초점 정량화 방법은 고주파 성분의 크기에 따라서 초점 정량화를 수행하므로 초점이 맞지 않은 부분에 고주파 성분이 있는 경우 성능이 저하된다는 단점이 있다. 본 논문에서는 이를 극복하기 위하여 효과적인 대역필터를 설계하였으며 제안하는 방법이 기존에 방법에 비해서 성능이 우수함을 시뮬레이션 및 실험을 통해 입증하였다.

• 제어로봇시스템학회논문지
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• 제22권2호
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• pp.139-146
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• 2016

Recently, popularity of 3D technology has been growing significantly and it has many application parts in the various fields of industry. In order to overcome the limitations of 2D machine vision technologies based on 2D image, we need the 3D measurement technologies. There are many 3D measurement methods as such scanning probe microscope, phase shifting interferometry, confocal scanning microscope, white-light scanning interferometry, and so on. In this paper, we have used the extended depth of focus (EDF) algorithm among 3D measurement methods. The EDF algorithm is the method which extracts the 3D information from 2D images acquired by short range depth camera. In this paper, we propose the EDF algorithm using the edge informations of images and the average values of all pixel on z-axis to improve the performance of conventional method. To verify the performance of the proposed method, we use the various synthetic images made by point spread function(PSF) algorithm. We can correctly make a comparison between the performance of proposed method and conventional one because the depth information of these synthetic images was known. Through the experimental results, the PSNR of the proposed algorithm was improved about 1 ~ 30 dB than conventional method.

• 한국산업정보학회논문지
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• 제25권6호
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• pp.85-94
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• 2020

급변하는 마케팅 환경에서 조직학습의 중요성이 증대되고 있다. 다양한 관리자들의 특성 중 조절초점이론과 기업의 상층부 이론을 결합하여 조절초점이 조직의 학습활동에의 세 가지 영역(학습활동의 넓이, 깊이, 속도)에 미치는 영향을 연구하였다. 수도권의 중소중견 기업의 중간관리자 이상의 간부들을 중심으로 설문을 진행하였다. 관리자의 촉진초점은 학습의 넓이와 깊이 그리고 속도에 모두 정의 영향을 미치는 것을 확인하였고, 특히, 학습의 넓이 예방초점보다 유의미하게 높은 수준의 영향을 미치는 것을 확인하였다.

• 대한기계학회논문집B
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• 제23권3호
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• pp.398-407
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• 1999

In the present image processing technique, the concept of the gradient indicator(GI) has been introduced to find out the depth-of-field in sizing large particles ranging from $30{\mu}m$ to $30{\mu}m$ where using of the concept of the normalized contrast value(VC) is not appropriate. The gradient indicator is defined as the ratio of the local value to the maximum possible value of the gray-level gradient in an image frame. The gradient indicator decreases with the increases of the particle size and the distance from the exact focal plane. A particle is considered to be in focus when the value of the gradient indicator at its image boundary stays above a critical value. This critical gradient indicator($GI_{critical}$) is defined as the maximum gradient indicator($GI_{max}$) subtracted by a constant ${\Delta}GI$ which is to account for the particle-size effect. In the present ca.so, the value of ${\Delta}GI$ was set to 0.28 to keep the standard deviation of the measured particles mostly within 0.1. It was also confirmed that, to find the depth-of-field for small particles(${\leq}30{\mu}m$) with the same measurement accuracy, tho concept of the critical normalized contrast($VC_{critical}$) is applicable with 85% of the maximum normalized contrast value($VC_{max}$). Finally, the depth-of-field was checked for the size range between $10{\mu}m$ and $300{\mu}m$ when the both in-focus criteria ($GI_{critical}$ and $VC_{critical}$) were adopted. The change of the depth-of-field with the particle size shows good linearity in both the VC-applicable and the GI-applicable ranges with a reasonable accuracy.

• 한국IT서비스학회지
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• 제9권1호
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• pp.91-111
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• 2010

An efficient industry structure is essential for competitive IT Service industry in a global world. The purpose of this research is to derive a policy direction paradigm for strengthening IT service industry structure. To find an effective policy direction, an in-depth analysis on deep-rooted problems of IT service industry has been conducted. The root-causes of industry problems are found with new perspectives on IT service industry. Past and present policies on IT service industry have been reviewed based on desirable industry behavior. A new policy paradigm and a roadmap for efficient industry policy are suggested. To justify adequacy of new policy direction, global benchmarking has been performed. USA, Germany, and Japan's IT service industry has been reviewed based on global competitiveness and desirable eco-system. And an in-depth analysis has been performed for two big competitors, India and China, The adequacy of the new policy paradigm has been tested, and mostly approved. IT service industry policy needs to be transformed from manufacturing concepts to service concepts, from domestic focus to global focus, from zero-sum policy to positive-sum policy, from supplier focus to market focus, from internal industry itself to co-growth with main industries. etc. The results of this study can be used for policy adjusting and policy making to strengthen IT service industry's global competitiveness and to improve long-term performance of Korean economy. Further in-depth researches with quantitative analysis will be needed to fully justify the adequacy of the derived new policy directions.