• Journal of the Korea society of information convergence
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• v.6 no.2
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• pp.51-55
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• 2013

The accomodation is made to see near objects. This accomodation have different characteristics from individual to individual. Difference also occurs accommodation of the theory and real. This is accomodative-lag. Depth of focus directly affects the accomodative-lag. Depth of focus is affected by the refractive power and the size of the pupil. Depth of focus becomes deeper as the size of the pupil is small, the refractive power is increased. The accomodative-lag occur more as depth of focus is deep. In this paper, a study was made of the relationship of the accomodative-lag and refractive power. A Monocular Estimation Method(MEM) use for measuring the accomodative-lag. Results were measured by MEM, it tended to increase the refractive power so as to increase the accodative-lag. The accomodative-lag amount was measured at 0.51D. Men were measured at 0.52D, women were measured at 0.49D. The accomodative-lag by gender tended also increases the amount of refractive power increases.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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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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• v.20 no.3
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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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• v.1 no.2
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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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• v.1 no.2
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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.

• Journal of Broadcast Engineering
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• v.16 no.5
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• pp.883-893
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• 2011

In this paper, we propose a novel focus measure that determines in-focus and out-of-focus region in an image. In addition, we achieved extended depth of field by blending the acquired image and Wiener filtered image using a decision map based on the designed focus measure. Since conventional focus measures are based on the amount of high frequency components in an acquired image, the measures may not be accurate if there exist high frequency components in out-of-focused region. To overcome the problem, we designed the novel focus measure based on effective band pass filtering. In simulations and experiments, the proposed method showed better performance than existing methods.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.2
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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.

• Journal of Korea Society of Industrial Information Systems
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• v.25 no.6
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• pp.85-94
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• 2020

The importance of organizational learning is increasing. Drawing on regulatory focus theory and upper echelon theory, this study aims to identify the relationship of the regulatory focus of managers and three aspects of organizational learning, namely breadth, depth, and speed of organizational learning. While identifying the significant influence of promotion focus on the three aspects of organizational learning, we found that the influence of promotion focus of breadth of organizational learning is statistically stronger than that of prevention focus.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.3
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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.

• Journal of Information Technology Services
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• v.9 no.1
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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.