• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1995-1996
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• 2011

영상 혹은 이미지 내에서 특정 물체를 검출하기 위한 일반적인 방법으로 비올라 존스(Viola-Jones) 알고리즘을 많이 사용하고 있으나 이 방법은 배경의 픽셀이 거의 동일한 값일 때에는 매우 높은 검출률을 보이는 반면 다양한 배경과 물체가 복합적으로 이루어져 있는 이미지의 경우에는 물체 검출 시 오인식 할 가능성이 매우 높다. 이러한 단점들은 얼굴 인식 시스템을 개발함에 있어 매우 불리하게 적용될 수 있는데, 본 연구는 얼굴인식 출입통제 시스템을 개발하는 과정에서 발생하는 이러한 문제점을 보완하기 위하여 비올라 존스 알고리즘에서 이용되는 하 라이크 피춰(Harr-like feature)에 새로운 형태의 사각 특징(Rectangular feature) 및 분산 특징(Varience feature) 추가하여 복잡한 배경에서도 물체 검출 성능을 향상시킬 수 있는 방법을 제안한다.

• The Journal of the Korea Contents Association
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• v.18 no.11
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• pp.484-492
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• 2018

This study examined the effects of field complexity and type of target objects on the performance in baggage screening task. A total of 62 participants(male: 45.2%, female: 54.8%) participated and their mean age was 22.88. The simulated baggage screening task was developed for this study and after the orientation and task exercises, main experiment session was conducted. Participants performed a total of 200 tasks and 40(20%) contained target object. The complexity was set at three levels: high, middle, and low levels and the number of background items contained 20, 14. and 8 respectively. The type of target was set as gun, knife, liquid, and righter. The dependent variables were hit ratio and reaction time. The results showed that the hit ratio decreased and reaction time increased significantly as field complexity increased, and they varied depending on the type of target. The hit ratio of the knife was the highest and liquid lowest and reaction time of the knife was the fastest and liquid slowest. In addition, the interaction effect was also significant. Knife was not affected by complexity, however, small item such as lighter was most affected by complexity.

• Archives of design research
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• v.14 no.4
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• pp.157-165
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• 2001

The method to make ceramic pigments for 4 colour instead of ink in the process of the of set-printing and put them on the decal paper in the ceramic industry has been used to produce complicated images such as photographs or famous masterpieces. Offset-printing which is the production method for mass production, had enough worth to suffer the past high price of the production line. But today it is not suitable for the production method of small quantity and many kinds corresponding to needs for the various tastes and designs of consumers. Therefore I will put 4 colour printing method on the silkscreen, handiwork, suitable for the production method for small quantities and many variations to develop the methods that permit to cost effectively reproduce complex, high resolution, multicolor images. The study is expected to give value to ceramists who do various works and to be offered as the foundation in the field of design and expression.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.3
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• pp.62-70
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• 2011

Nowadays image sensor is an essential component in many multimedia devices, and it is covered by a color filter array to filter out specific color components at each pixel. We need a certain algorithm to combine those color components reconstructed a full color image from incomplete color samples output from an image sensor, which is called a demosaicking process. Most existing demosaicking algorithms are developed for ideal image sensors, but they do not work well for the practical cases because of dissimilar characteristics of each sensor. In this paper, we propose a new demosaicking algorithm in which the color filter characteristics are fully utilized to generate a good image. To demonstrate significance of our algorithm, we used a commerically available sensor, CBN385B, which is a sort of Honeycomb-style CFA(Color Filter Array) CCD image sensor. As a performance metric of the algorithm, PSNR(Peak Signal to Noise Ratio) and RGB distribution of the output image are used. We first implemented our algorithm in C-language for simulation on various input images. As a result, we could obtain much enhanced images whose PSNR was improved by 4~8 dB compared to the commonly idealized approaches, and we also could remove the inclined red property which was an unique characteristics of the image sensor(CBN385B).Then we implemented it in hardware to overcome its problem of computational complexity which made it operate slow in software. The hardware was verified on Spartan-3E FPGA(Field Programable Gate Array) to give almost the same performance as software, but in much faster execution time. The total logic gate count is 45K, and it handles 25 image frmaes per second.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.3 s.357
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• pp.65-71
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• 2007

We propose a pixel-level automatic calibration circuit scheme that initializes a capacitive fingerprint sensor LSI to eliminate the influence of the surface condition and environment, which is degraded by dirt during long-time use, process variation and ambient temperature. The sample chip is fabricated on $0.35{\mu}m$ standard CMOS process. The calibration is executed by optimizing the reference voltage in each pixel to make the sensor signals of all pixels the same. The calibration control circuit is composed of the sensing circuit and charge pumping circuit, and calibrates all pixels in a short time. 16-level gray scale fingerprint images can be captured to increase the accuracy of identification. This confirms that the scheme is effective for capturing consistent clear images during long-time use.

• Proceedings of the Korea Information Processing Society Conference
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• 2021.05a
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• pp.521-524
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• 2021

HEIF (High Efficiency File Format)는 MPEG에서 개발된 이미지 포맷으로써, 비디오 코덱인 H.265를 활용하여 정지된 화면을 하나의 이미지 형태로 저장할 수 있도록 개발된 컨테이너이다. 아이폰은 2017년부터 HEIF를 사용하고 있으며, 2019년부터는 갤럭시 S10과 같은 안드로이드 기기도 해당 포맷을 지원하고 있다. 이 포맷은 우수한 압축률을 가지도록 이미지를 제공할 수 있으나, 복잡한 내부 구조를 가지고 있으며 기기나 소프트웨어 간 호환성이 현저하게 부족하여 일반적으로 사용되는 JPEG(또는 JPG) 파일을 대체하기에는 아직 대중적이지 못한 상황이다. 하지만 이미 많은 기기에서 HEIF를 사용하고 있음에도 불구하고 디지털 포렌식 연구는 부족한 상황이다. 이는 디지털 포렌식 조사 과정에서 파일 내부에 포함된 정보의 파악이 미흡하여 잠재적인 증거를 놓칠 수 있는 위험에 노출될 수 있다. 따라서 본 논문에서는 아이폰에서 촬영된 HEIF 형식의 사진 파일과 갤럭시에서 촬영된 모션 포토 파일을 분석하여 파일 내부에 포함된 정보와 특징들을 알아본다. 또한 이미지 뷰어기능을 지원하는 소프트웨어를 대상으로 HEIF에 대한 지원 여부를 조사하고 HEIF 뷰어를 분석하는 포렌식 도구의 요구사항을 제시한다.

• Journal of the Korea Computer Graphics Society
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• v.17 no.2
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• pp.17-26
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• 2011

This paper presents an interactive progressive image transmission method, which enables a remote user to interactively select and transmit preferred regions from an index image. Our enhanced quadtree decomposition using PSNR-based rules and new implicit quadtree coding provide better rate-distortion performance than previous quadtree coders as well as leading bit plane methods. An adaptive traversal of child nodes is introduced for better visual display of restored images. Depth-first traversal combined with breadth-first traversal of the quadtree to accomplish interactive transmission as presented, results in a method that provides competitive performance at a low level of computational complexity. Moreover, our decoding requires only simple arithmetic which is enabling our method to be used for real-time mobile applications.

• Journal of Korea Multimedia Society
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• v.7 no.1
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• pp.44-53
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• 2004

This paper aims at presenting high quality at low resolution apply by a new antialiasing method for voxelized implicit surfaces. Implicit surfaces create a unique type of 3D-modeling. Some use of implicit surfaces are scientific and medical visualization, animation, medical simulation and interactive modeling. One of previous antialiasing methods for implicit surfaces presented by raytracing or texture mapping is making use of a stochastic sampling. But this method requires more calculation time and costs which is caused by complicated and difficult implicit functions. In the meanwhile, voxelized implicit surfaces generally use high resolution for good quality images but it costs to generate. In order to this problem, this paper suggests a shifted double Z-buffer which is very simple, more efficient and easy. Tn addition, there are applied box-filter and tent-filter to the double Z-buffer antialiasing method for better images. For results this method generate high quality image and it is easy to apply to various filters and is able to extend to multi Z-buffer.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.47 no.1
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• pp.1-6
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• 2010

The lens distortion in the machine vision system is inevitable phenomenon. Distortion is getting worse, due to the selection of lens in the trend of reducing prices and size of the system. In this trend, the distortion correction becomes more important. But, the traditional correction methods has problems, such as complexity and requiring more operations. Effective distorted digital image correction is the precondition of target detection and recognition based on vision inspection. To overcome the disadvantage of traditional distortion correction algorithms, such as complex modeling, massive computation and marginal information loss, an image distortion correction algorithm based on photogrammetry method is proposed in this paper. In our method, we use the lattice image as the measurement target. Through the experimental results, we could find that we can reduce the processing time by 4ms. And also the inspection failure rate of our method was reduced by 2.3% than human-eyes inspection method.

• Proceedings of the Korea Contents Association Conference
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• 2014.11a
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• pp.143-144
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• 2014

"카카오톡"이 세계시장으로 확대하기를 위해서 중미일의 대표적인 모바일 SNS(Facebook, Wechat, Linkedln)와 대비를 통하여 GUI디자인을 중심으로 분석이 이루어져야 할 필요성이 있다. 연구결과를 통하여 본 카카오톡 GUI디자인의 특징과 문제점은 다음과 같다. 첫째, 굵은 선으로 아이콘 구성하는 방법이 전체 스타일에 영합하지만 화면이 복잡해 보이는 측면이 있다. 둘째, 서브메뉴에서 아이콘과 앱링크, 광고이미지 등 다양한 요소를 한꺼번에 놓으면 혼란한 측면이 있다.