• Journal of the Institute of Convergence Signal Processing
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• v.12 no.3
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• pp.176-180
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• 2011

Even though algorithms for watermark embedding and extraction step are important issue for digital watermarking, watermark selection and post-processing can give us an opportunity to improve our algorithms and achieve higher performance. For this reason, we summarized the possibilities of improvements for digital watermarking by referring to the watermark merging techniques rather than embedding and extraction algorithms in this paper. We chose Cox's function as main embedding and extraction algorithm, and multiple barcode watermarks as a watermark. Each bit of the multiple copies of barcode watermark was embedded into a gray-scale image with Cox's embedding function. After extracting the numbers of watermark, we applied the watermark merging techniques; including the simple merging, N-step iterated merging, recover merging and combination of iterated-recover merging. Main consequence of our paper was the fact of finding out how multiple barcode watermarks and merging techniques can give us opportunities to improve the performance of algorithm.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1689-1694
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• 2005

Face detection plays an important role in face recognition, video surveillance, and human computer interface. In this paper, we present a face detection system using eye detection with progressive thresholding from a digital camera. The face candidate is detected by using skin color segmentation in the YCbCr color space. The face candidates are verified by detecting the eyes that is located by iterative thresholding and correlation coefficients. Preprocessing includes histogram equalization, log transformation, and gray-scale morphology for the emphasized eyes image. The distance of the eye candidate points generated by the progressive increasing threshold value is employed to extract the facial region. The process of the face detection is repeated by using the increasing threshold value. Experimental results show that more enhanced face detection in real time.

• Journal of Information Display
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• v.1 no.1
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• pp.20-24
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• 2000

We propose on a novel vertical configuration (VC) for a helix-deformed ferroelectric liquid crystal (HDFLC) display that has fast response, high contrast, analog gray scale capability, and wide-viewing characteristics. In contrast to a conventional HDFLC in a planar geometry, smectic layers arrange themselves parallel to the substrates, and thus, extremely uniform alignment of molecules in large area is naturally achieved in our new configuration without additional processes such as the rubbing and/or electric field treatment. Moreover, with a proper design of electrode patterns on the same substrate, multidomain switching is easily realized without employing any complex process of alignment. Our new VC-HDFLC is expected to provide a viable technology to produce a next-generation large area LCD suitable for processing the dynamic image at a video-rate.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.215-217
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• 2006

This paper presents an area efficient 8-bit current digital to analog convector (DAC) which is applied to 240 channels Active Matrix - Organic Light Emitting Diode (AMOLED) data driver. The proposed circuit constitutes 4-bit binary weighted current DAC and 4-bit switched capacitor cyclic DAC. The proposed DAC has about 70% smaller area than that of the typical binary weighted current DAC. We overcome sampling time by reducing the number of repetition phases so that it can display 8-bit gray scale image.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.7
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• pp.1340-1345
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• 2010

FRC(Frame Rate Control) has been applied to the monitor and TV product as part of cost-saving in many flat panel display manufacturers. As FRC can represent the same number of gray scale level with bits of a smaller amount than bits of the input image data, it is widely used. However, FRC causes visual artifacts by using repeatedly pre-designed the FRC unit size of block pattern in display devices. Therefore, this paper analyzes the cause of the visual artifacts. And in order to improve them, it proposed the pattern arrangement of FRC unit blocks through frame rolling method as analytic solution for the first time. So, we could embody causes of FRC noise. Using the proposed structure, more robust pattern to FRC noise will be designed.

• Bulletin of the Korean Chemical Society
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• v.26 no.6
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• pp.966-970
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• 2005

To measure the thickness of liquid films from 10 to 60 ${\mu}m$, we used photochromic dye activation. And we used silicone oil with 10 centi-Stokes and commercial photochromic dyes. To make films with exact and known thicknesses, we used two glass wafers. A film formed between two wafers after placing a drop of liquid of known volume on one wafer and covering the other. The film thickness could be estimated from the diameter of wafer and the dropped liquid volume. To quantitatively evaluate the result, captured the images using digital camera then analyzed the images using the image tool. The gray scale intensity using the captured images of activated dye with these thicknesses showed the repeatability below ${\pm}$ 1.0% when measured with a silicone oil solution containing 0.1% SO and SO-ANTH dyes. And we showed that photochromic dye activation method could be used to measure our liquid film thickness ranges.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 1999.11a
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• pp.153-156
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• 1999

본 연구는 시트 커버지로 선호하는 직물의 특성을 파악하고자 하였다. 직물디자인의 평가 요소 중 pattern에 초점을 맞추었으며 부수적으로 색상에 대한 선호도 평가를 수행하였다. 직물 pattern 디자인은 PP(Primitive pattern)와 RPU(Repeated pattern unit)의 세부항목에 대한 평가를 통해 전체 직물패턴에 대한 평가가 가능하다. Pattern 특징 평가를 위한 1차 설문에서 소재와 색상의 요인들의 영향을 최소화하기 위해 sample 직물을 gray-scale image로 제시하여 세부항목을 평가하였다. 1차 설문결과로써 pattern 특성을 대표하는 4개의 직물샘플을 선정하였다. 2차 설문에서 4개의 대표 sample을 열차용 시트에 rendering 하여 선호도 평가를 수행하였으며, 색상 선호도 평가는 5가지 색상 군집에 대한 선호를 평가하였다. 선호도 평가 결과 시트 커버지로 선호하는 직물의 특징은 PP의 특징에 상관없이 RPU의 돌출성이 적은 pattern이었다 또한 색상은 초록색과 파랑색을 선호하는 것을 알 수 있었다. 추후 이러한 결과를 통한 시트 커버 직물의 디자인 및 선택이 이루어져야 할 것이다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.479-480
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• 2006

We have studied the viewing angle control of a twist nematic liquid crystal display (TN-LCD). The TN-LCD exhibits a bad image quality along vertical direction, due to characteristics such as low contrast ratio and gray scale inversion. The proposed new TN-LCD has the function of switching between the wide viewing mode and narrow viewing angle mode using two tilted LC layers at both sides of a TN-cell. Tilt angles of the two LC layers, $14^{\circ}$ and $60^{\circ}$ were required in both wide viewing angle and narrow viewing angle modes, respectively.

• Computers and Concrete
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• v.7 no.6
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• pp.511-522
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• 2010

A color based segmentation procedure and a modified signature technique have been applied to the detection and analyses of complicated void shapes in cemented materials. The gray-scale segmentation and available signature methods were found to be inefficient especially for the analyses of complicated void shapes. The applicability of the developed methodology has been demonstrated on artificially prepared cemented materials made of self compacted concrete material. In order to characterize the void shapes in the investigated sample images, two new shape parameters called as coefficients of inclusion and exclusion have been proposed. When compared with the traditional use of the signature method, it was found that the methodology followed herein would better characterize complicated void shapes. The methodology followed in this study may be applied to the analysis of complicated void shapes that are often encountered in other cementitious materials such as clays and rocks.

• Journal of the Semiconductor & Display Technology
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• v.9 no.3
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• pp.59-63
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• 2010

This paper proposes computer visual inspection algorithms for various LCD defects which are found in a manufacturing process. Modular vision processing steps are required in order to detect different types of LCD defects. Those key modules include RGB filtering for pixel defects, gray-scale morphological processing and Hough transform for line defects, and adaptive threshold for spot defects. The proposed algorithms can give users detailed information on the type of defects in the LCD panel, the size of defect, and its location. The machine vision inspection system is implemented using C language in an embedded Linux system for a high-speed real-time image processing. Experiment results show that the proposed algorithms are quite successful.