• 한국레이저가공학회지
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• 제2권3호
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• pp.19-31
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• 1999

This paper introduces the monitoring scheme of laser welding quality using neural network. The developed monitoring scheme detects light signal emitting from plasma formed above the weld pool with optic sensor and DSP-based signal processor, and analyzes to give a guidance about the weld quality. It can automatically detect defects of laser weld and further give an information about what kind of defects it is, specially partial penetration and porosity among the interior defects. Those could be detected only by naked eyes or X-ray after welding, which needs more processes and costs in mass production. The monitoring scheme extracts four feature vectors from signal processing results of optical measuring data. In order to classify pattern for extracted feature vectors and to decide defects, it uses single-layer neural network with perceptron learning. The monitoring result using only the first feature vector shows confidence rate in recognition of 90%($\pm$5) and decides whether normal status or defects status in real time.

• 제어로봇시스템학회논문지
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• 제18권1호
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• pp.7-12
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• 2012

In this paper, we present an effective viewpoint estimation algorithm for the Moving parallax barrier method of 3D display mobile device. Moving parallax barrier is designed to overcome the biggest problem, the limited view angle. To accomplish it, the position of the viewer's eyes or face should be estimated with strong stability and no latency. We focus on these requirements in the poor performance of mobile processors. We used a pre-processing algorithm in order to overcome the various illumination changes. And, we combined the conventional Viola-Jones face detection method and Optical-flow algorithm for robust and stable viewpoint estimation. Various computer simulations prove the effectiveness of the proposed method.

• 대한전자공학회논문지
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• 제24권4호
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• pp.646-651
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• 1987

The photoconductive multilayer composed of glassy, porous, and fine-grained layers was fabdricated with Se and Sb2S3 by vacuum evaporation in order to be used as vidicon target. And its electrical, optical properties were investigatee. The fabrication conditions were as follow: the glassy layer was first deposited to have the thickness of 6500 \ulcornerat the deposition rate of 250\ulcornersec. High photosensitivity(\ulcorner=1) was obtained but its shortcoming was high dielectric constant. Therefore, the porous layer was added to lower dielectric constant and had 7500\ulcornerthick in the argon gas ambikent of 7x10-\ulcorner And the fine-grained layer was formed to prevent secondary electron emission and obtain good resolution. Its thickness was about 1700\ulcorner For the given vidicon target, the light transfer characteristic, that is, photosensitivity (\ulcorner) was measured to be 0.8 at the applied voltage of 25V. The spectral sensitivity was quite similar to that of the human eyes.

• 한국안광학회지
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• 제5권2호
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• pp.55-58
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• 2000

정상인을 대상으로 5년 동안에 매년 안경원을 방문하여 시력을 측정한 사람 160명 360안(남 : 79명 여 : 81명)을 조사하였고 안경원에서 교정한 교정안경 굴절력을 눈의 굴절력으로 간주하여 원용안경의 굴절력만을 조사하였다. 1. 나이가 어릴수록 근시의 굴절력 증가가 많았다. 2. 우리나라 학제 기간 중 초등학교 재학기간에 근시의 증가율이 가장 컸다. 3. 초등학교 기간에는 4개월 중학교 6개월 고등학교 12개월만에 안경을 재 교정해야 할 것으로 조사되었다.

• Journal of Information Technology Applications and Management
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• 제10권4호
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• pp.135-147
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• 2003

With the development of multimedia and optical technologies, application systems with facial features hare been increased the interests of researchers, recently. The previous research efforts in face processing mainly use the frontal images in order to recognize human face visually and to extract the facial expression. However, applications, such as image database systems which support queries based on the facial direction and image arrangement systems which place facial images automatically on digital albums, deal with the directional characteristics of a face. In this paper, we propose a method to detect facial directions by using facial features. In the proposed method, the facial trapezoid is defined by detecting points for eyes and a lower lip. Then, the facial direction formula, which calculates the right and left facial direction, is defined by the statistical data about the ratio of the right and left area in facial trapezoids. The proposed method can give an accurate estimate of horizontal rotation of a face within an error tolerance of $\pm1.31$ degree and takes an average execution time of 3.16 sec.

• 조명전기설비학회논문지
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• 제25권11호
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• pp.1-13
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• 2011

The purpose of this study is the realization of LED light environment closely resembling the Autumn daylight which people feel comfortable with. This research was conducted through an optical experiment and Emotional evaluation through human's eyes. Human beings are affected by the color of light, quality and light intensity. Unlike the past when human beings have worked mainly in daylight, the urbanites today spend most of the time in indoor spaces. Therefore, the artificial light is needed to strive toward a spectrum of daylight. This study is purposed to provide the pleasant light environment for human beings and build its database. This study course is expected to contribute to the new design methodology of the related fields under the development of the LED emotional lighting color.

• JSTS:Journal of Semiconductor Technology and Science
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• 제11권1호
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• pp.1-5
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• 2011

To enter next process control, numerous approaches, including run-to-run (R2R) process control and fault detection and classification (FDC) have been suggested in semiconductor manufacturing industry as a facilitation of advanced process control. This paper introduces a novel type of optical plasma process monitoring system, called plasma eyes chromatic system (PECSTM) and presents its potential for the purpose of fault detection. Qualitatively comparison of optically acquired signal levels vs. process parameter modifications are successfully demonstrated, and we expect that PECSTM signal can be a useful indication of onset of process change in real-time for advanced process control (APC).

• 한국산학기술학회논문지
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• 제4권1호
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• pp.17-21
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• 2003

산업용 뿐만 아니라 보석용으로 가치가 있는 합성 및 천연사파이어를 인위적으로 청색발색효과를 높이기 위해 확산 처리한 경우, 종래 육안감정에 의해서는 확산처리 유무 및 불순물 주입 정도에 따른 광학적 특성의 감정이 어려운 문제가 있었다. 비파괴적이고 빠른 시간안에 정량적인 분석을 위해 FTIR(Fourier transformation infra-red) 분석을 이용하여 해결할 수 있음을 확인하였다. 기존의 고가 SIMS(secondary ion mass spectrometry) 등 고가 진공분석장비에 비하여 획기적으로 3분 이내의 분석을 통하여 경제적, 비파괴적인 분석이 가능하여, 관련 업체에 도입되는 경우 제안된 전용 FTIR 설비를 이용하여 처리사파이어의 정밀감정이 가능하였다.

• Current Optics and Photonics
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• 제1권1호
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• pp.34-44
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• 2017

Stereoscopic (S3D) displays present different images to the two eyes. Temporal multiplexing and spatial multiplexing are two common techniques for accomplishing this. We compared the effective resolution provided by these two techniques. In a psychophysical experiment, we measured resolution at various viewing distances on a display employing temporal multiplexing, and on another display employing spatial multiplexing. In another experiment, we simulated the two multiplexing techniques on one display and again measured resolution. The results show that temporal multiplexing provides greater effective resolution than spatial multiplexing at short and medium viewing distances, and that the two techniques provide similar resolution at long viewing distance. Importantly, we observed a significant difference in resolution at the viewing distance that is generally recommended for high-definition television.

• 한국안광학회지
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• 제7권2호
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• pp.107-112
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• 2002

60세 이상의 노인에서 나타나는 노인성 백내장과 군날개의 분포와 이들 안질환과 시력과의 관계를 228명 456안을 대상으로 조사하여 다음과 같은 결과를 얻을 수 있었다. 백내장과 군날개를 가진 사람은 총 검사대상 228명(456안)가운데 125명(250안)으로 54.8%로 조사되었고, 125명 가운데 백내장은 44.8%, 군날개 55.2%로 조사되었다. 백내장의 연령별 유병율은 60대가 46.4%, 70대 37.5%, 80대 이상에서 16.1%로 조사되었다. 백내장을 가진 사람의 교정시력은 0.1이하가 14.3%, 0.1~0.3이 14.3%, 0.4~0.6이 36.6%, 0.7 이상이 40.2%로 안경으로 시력교정 후에도 정상적인 시생활을 할 수 없는 사람이 59.8%로 조사되었다. 군날개의 연령별 유병율은 60대 60.9%, 70대 26.1%, 80대 이상에서 13%로 조사되었고, 군날개를 가진 사람의 교정시력은 0.1이하가 5.1%, 0.1~0.3이 5.8%, 0.4~0.6이 20.3%, 0.7이상이 68.8%로 조사되었다.