• Journal of Korea Multimedia Society
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• v.15 no.11
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• pp.1369-1376
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• 2012

In this paper, we propose 2D industrial image registration method for the detection of defects. Proposed method performs preprocessing to smooth the original image with the preservation of the edge for the robust registration against general noise. Then, x-direction gradient magnitude image and corresponding binary image are generated. Density analysis around neighborhood regions per pixel are performed to generate feature image for preventing mis-registration due to moire-like patterns, which frequently happen in industrial images. Finally, 2D image registration based on phase correlation between feature images is performed to calculate translational parameters to align two images rapidly and optimally. Experimental results showed that the registration accuracy of proposed method for the real industrial images was 100% and our method was about twenty times faster than the previous method. Our fast and accurate method could be used for the real industrial applications.

• Korean Journal of Optics and Photonics
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• v.12 no.1
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• pp.25-31
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• 2001

The Talbot effect of an elongated circular (EC) grating composed of a line grating and two semicircular gratings with well matched pitches is experimentally presented. As the relative positions between the fixed EC grating and the moving Talbot image of another EC grating or a self Talbot image are one-dimensionally deformed, we can visually observe moire fringes generated by their superposition. Two examples of their applications, that is, the measurement of the wedged angle of a wedged prism and of the fine rotational angle of a mirror are described.cribed.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.3
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• pp.139-146
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• 2004

A 2D/3D complex optical system and its vision inspection algerian is proposed and implemented as a single probe system for high speed, precise vision inspection of the solder pastes. One pass un length labeling algorithm is proposed instead of the conventional two pass labeling algorithm for fast extraction of the 2D shape of the solder paste image from the recent line-scan camera as well as the conventional area-scan camera, and the optical probe path generation is also proposed for the efficient 2D/3D inspection. The Moire interferometry-based phase shift algerian and its optical system implementation is introduced, instead of the conventional laser slit-beam method, for the high precision 3D vision inspection. All of the time-critical algorithms are MMX SIMD parallel-coded for further speedup. The proposed system is implemented for simultaneous 2D/3D inspection of 10mm${\times}$10mm FOV with resolutions of 10 ${\mu}{\textrm}{m}$ for both x, y axis and 1 ${\mu}{\textrm}{m}$ for z axis. Experiments conducted on several nBs show that the 2D/3D inspection of an FOV, excluding an image capturing, results in high speed of about 0.011sec/0.01sec, respectively, after image capturing, with $\pm$1${\mu}{\textrm}{m}$ height accuracy.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.8
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• pp.5269-5279
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• 2014

The cause of defects in the PCB SMT assembly is mostly solder paste deposits. Conventional inspection methods for solder paste deposits suffer from slow speed, low reliability and high cost. Therefore, this paper proposes a method for calculating the height and region of solder paste on PCB using the 3D profiles without measuring the 2D image. The solder paste region is detected by the phase difference in the measurement points and the average phase on the whole surface of PCB. The high reliable height of the solder paste region is computed by the average of the measurement points' phase with repeatability and reliability. The experimental results revealed improvements of 17% in inspection time and 29% repeatability in the height calculation of the solder paste region, resulting in a high speed and less expensive system.

• The Journal of the Korea Contents Association
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• v.9 no.4
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• pp.189-197
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• 2009

A digital image usually has 8 bits of depth basically representing pixel intensity ranging for [0 255]. These pixel range allow 256 step levels of pixel values in the image. Thus the greyscale value for a given image is an integer. When we carry out interpolation of a given image for resizing we have to round the interpolated value to integer which can result in loss of quality on perceived color values. This paper proposes a new method for recovering this loss of information during interpolation process. By using the proposed method the pixels tend to regain more original values which yields better looking images on resizing.

• Journal of the Korean Society of Clothing and Textiles
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• v.27 no.2
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• pp.270-276
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• 2003

Methodology was suggested to analyze breast volume, base area of breast bulk. and surface area of breast using the 3D measurement system. Thirty-seven middle-aged (30s-40s) women wearing 80A brassiere were participated in this study. Image of the upper body was captured by Phase-shifting moire. The posture of the subject was adjusted to get the full image of the right breast. Rapidform 2001 was used for the analysis of the images. The mean breast volume was 547.0㎤ and mean base area of breast bulk was 235. I$\textrm{cm}^2$ It was also found that the volume(r=0.169) and surface area of breast(r=10.242) were loosely correlated with the circumference difference between top and under breast. Therefore, it is noted that current selection criterion of cup size based on the difference in the two kinds of breast circumference is inadequate. The result of this study is expected to contribute to the design of ergonomic brassiere as well as surgical operations in the medical field.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1997.04a
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• pp.48-53
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• 1997

Electronic Speckle Pattern Interferometry(ESPI) using the Model 95 Ar laserm, a video system and an image processor was applied to the in-plane displacement measurements. Unlike traditional strain gauges or moire method, ESPI method requires no special surface preparation or attachments and can be measured in-plane displacement with no contact and real time. In this experiment wpecimen was loaded in parallel with a loadcell. The specimen was the cold rolled sdteel sheet of 2mm thickness, which was attached strain gauges. The study provides an example of how ESPI have been used to measure strain displacement in this specimen. The results measured by ESPI have been used to measure strain displacement in this specimen. The results measured by ESPI have been used to measure strain displacement in this specimen. The results measured by ESPI compare with the data which was measured by strain gauge method in tensile testing.

• Annual Conference of KIPS
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• 2016.04a
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• pp.286-288
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• 2016

기존에 카메라는 침입자를 탐지할 때 정확성이 부족하고 열화상카메라는 가격이 비싸고 열 측정이 되지 않는 상황일 경우 감시가 힘들다는 단점이 있다. 이러한 단점을 보완하기 위해 빛의 간섭 및 회절에 의한 무아레 현상을 이용하여 이상징후 탐지 및 활용방안을 제시하려한다. 지형의 높낮이 및 형상을 저장하고 침입자가 탐지되었을 경우 무아레 이미지를 기반으로 처음 설정했던 지형 데이터와 비교하여 외부인의 침입을 탐지한다. 미세한 움직임이나 변화에도 크게 이미지가 변하는 무아레 현상의 성질을 이용하여 이상징후를 탐지하는 것이다. 이상징후를 탐지 했을 경우 보안 담당관에게 알림을 전송하거나 경보를 울리는 이상징후 탐지 솔루션 및 활용방안을 제안한다.

• Journal of the Korean Graphic Arts Communication Society
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• v.20 no.2
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• pp.31-43
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• 2002

Screen printing is a stencil process whereby ink is transferred to the substrate through a stencil supported by a fine fabric mesh. Therefore screen had a tendency to distort and swell, as ink was deposited between the fibers, and were difficult to clean. The tow importance of stencil parameters that affect print quality are stencil thread diameter and the fabric thickness because of their influence on both ink deposit and print definition. Since screen printing inks can be formulated to adhere to almost any surface, and the printing process itself can be handled almost any substrate in a wide variety of shape, screen printing is a very versatile process. The small size pronting is reproduced image used screen printing because the surface of substrates is not suited at screen printing method. In screen printing, the need of high definition printing is gradually increasing according to developing special inks. A conventional haftone, so called AM screening, is simple and easy to implement, but the haftone dot patterns by using this method are not free for the moire fringe. This paper is used densitometry and image analysis to investigate relation with printing according to screen mesh, opening size and resolution of copy in image reproduction used FM screen. We had the good result of dot gain and tone reproduction on the screen printing of high definition using FM screen.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.12
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• pp.2747-2754
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• 2012

This thesis explains the development of multiple LCD system with the additional function to maximize the utilization of PC contents. The newly developed system is composed of host LCD and slave LCD. Host LCD decodes and outputs the image and voice of NTSC, PAL, SECAM signals. It also converts the decoded signals into LVDS signals before transmitting them to slave LCD stage. In addition, the installation of CF Memory and USB Memory helps display multi-media data. Unlike the host LCD, since not including the tuner and memory part, the slave LCD can't receive TV signals and play video signals. It only has the function to receive LVDS image signals and display on a LCD panel. This newly developed multi-LCD system has competitiveness in various aspects. With its simple structure, the failure rate, price and display power are relatively low due to its simplification of the control part. It has price and functional competitiveness as the product whose host LCD can control the entire slave LCD in terms of channel, volume, and video output.