• 한국의학물리학회지:의학물리
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• 제19권4호
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• pp.201-208
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• 2008

물리적 평가(physical evaluation)가 영상품질의 객관화와 정량화를 위한 토대를 제공함에도 불구하고, 부정확하고 가변적인 특성을 지닌 주관적 평가(subjective evaluation)가 영상평가에 중요한 역할을 하게 된다. 본 연구에서는 디지털 방사선 영상의 물리적 평가와 주간적 평가의 단점을 상호 보완하고 객관적 정량화를 위한 새로운 방법을 제안하고자 한다. 임상에 사용되고 있는 4대의 디지털 방사선 영상 촬영장치로부터 동일한 임상조건에서 흉부 팬톰 영상을 획득하였다. 물리적 영상평가를 위하여 디지털 흉부 팬톰 내에서 3개의 영역(폐, 심장, 그리고 복부)에 존재하는 CNR (contrast-to-noise ratio)를 측정하였고 분할(segmentation)과 정합(registration)등 다양한 영상처리기술이 적용되었다. 주관적 평가는 5명의 관찰자에 의한 저 대조도 물체의 식별 정도를 점수화 하였다. 두 평가의 특성을 보완 및 결합하고자 퍼지적분 이론이 도입되었다. 4대의 시스템으로부터의 평가결과가 비교되었으며, 물리적 평가와 주관적 평가가 항상 비례하지 않음을 보였다. 물리적 평가에서는 높은 점수를 보였던 시스템이 주관적 평가에서는 상대적으로 낮은 평가를 보였다. 본 연구에서 제안한 퍼지적분에 의한 영상평가의 정량화는 물리적 평가와 주관적 평가를 모두 포함하는 총체적인 평가 방법이며, 다양한 영상품질 평가에 유용할 것이라 사료된다.

• 한국산학기술학회논문지
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• 제18권10호
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• pp.597-602
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• 2017

본 논문에서는 군에서 사용하는 텍스타일 재료에 대한 항균성 시험방법의 신뢰성 확보 방안을 제시하고자 하였다. 항균성은 일반적으로 세균의 증식을 억제하고 유해한 균을 제거하는 것을 말하며, 항균성을 측정하는 시험방법은 텍스타일 재료의 특성과 형태에 따라 다양한 방법이 있다. 항균성 시험방법인 KS K 0693 '텍스타일 재료의 향균성 시험방법'에 따르면, 콜로니 수를 측정할 때 시험자가 육안으로 세어 측정한다. 이때 시험자의 숙달수준에 따른 측정오차가 발생할 가능성이 크며 자동화되지 않아 비교적 시간이 오래 걸린다. 이러한 단점을 개선하기 위해 영상처리 기술을 적용하여 향균도를 측정하는 방법을 제안한다. 시험자료는 '방탄헬멧 부유대조립체 완충패드'의 외피소재를 대상으로 하고, 공인시험기관에서 발급된 시험 성적서에 첨부된 배양배지 영상을 사용하였다. 배양배지 영상을 전처리 한 후 분할 및 이진화 처리 후 영상 내 입자의 수를 세어 콜로니수를 확인하는 방법을 제안한다. 제안하는 방법을 적용한 항균도 측정결과와 기존 시험방법의 측정결과를 비교한 결과, 제안하는 방법은 기존의 시험방법을 통한 항균성 측정결과 대비 0.9%p 정도의 차이를 보였다. 제안하는 방법은 측정자의 오차를 제거하여 신뢰성을 확보할 수 있으며 측정 시간이 짧다는 장점이 있다.

• 로봇학회논문지
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• 제19권1호
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• pp.65-70
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• 2024

Tool wear is considered an important issue in manufacturing and engineering, as worn tools can negatively impact productivity and product quality. Given that the wear status of tools plays a decisive role in the production process, measuring tool wear is a key task. Consequently, there is significant attention in manufacturing fields on the precise measurement of tool wear. Current domestic methods for measuring wear are limited in terms of speed and efficiency, with traditional methods being time-consuming and reliant on subjective evaluation. To address these issues, we developed a measurement module implementing the DeepContour algorithm, which uses image processing technology for rapid measurement and evaluation of tool wear. This algorithm accurately extracts the tool's outline, assesses its condition, determines the degree of wear, and proves more efficient than existing, subjective, and time-consuming methods. The main objective of this paper is to design and apply in practice an algorithm and measurement module that can measure and evaluate tool wear using image processing technology. It focuses on determining the degree of wear by extracting the tool's outline, assessing its condition, and presenting the measured value to the operator.

• Imaging Science in Dentistry
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• 제48권2호
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• pp.111-119
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• 2018

Purpose: This study was conducted to evaluate the accuracy of linear measurements of 3-dimensional (3D) images generated by cone-beam computed tomography (CBCT) and facial scanning systems, and to assess the effect of scanning parameters, such as CBCT exposure settings, on image quality. Materials and Methods: CBCT and facial scanning images of an anthropomorphic phantom showing 13 soft-tissue anatomical landmarks were used in the study. The distances between the anatomical landmarks on the phantom were measured to obtain a reference for evaluating the accuracy of the 3D facial soft-tissue images. The distances between the 3D image landmarks were measured using a 3D distance measurement tool. The effect of scanning parameters on CBCT image quality was evaluated by visually comparing images acquired under different exposure conditions, but at a constant threshold. Results: Comparison of the repeated direct phantom and image-based measurements revealed good reproducibility. There were no significant differences between the direct phantom and image-based measurements of the CBCT surface volume-rendered images. Five of the 15 measurements of the 3D facial scans were found to be significantly different from their corresponding direct phantom measurements(P<.05). The quality of the CBCT surface volume-rendered images acquired at a constant threshold varied across different exposure conditions. Conclusion: These results proved that existing 3D imaging techniques were satisfactorily accurate for clinical applications, and that optimizing the variables that affected image quality, such as the exposure parameters, was critical for image acquisition.

• Journal of Positioning, Navigation, and Timing
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• 제8권4호
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• pp.175-181
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• 2019

This paper suggests a velocity integration algorithm for Synthetic Aperture Radar (SAR) motion measurement to reduce discontinuity of range error. When using position data from Embedded GPS/INS (EGI) to form SAR image, the discontinuity of the data degrades SAR image quality. In this paper, to reduce the discontinuity of EGI position data, EGI velocity integration is suggested which obtains navigation solution by integrating velocity data from EGI. Simulation shows that the method improves SAR image quality by reducing the discontinuity of range error. INS is a similar algorithm to EGI velocity integration in the way that it also obtains navigation solution by integrating velocity measured by IMU. Comparing INS and EGI velocity integration according to grades of IMU and GPS, EGI velocity integration is more suitable for the real system. Through this, EGI velocity integration is suggested, which improves SAR image quality more than existing algorithms.

• Fibers and Polymers
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• 제6권1호
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• pp.79-81
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• 2005

Fuzz on the fabrics, which is the fibers protruded from the fabric surface, is very important in view of appearance quality, since it causes unpleasant appearance on the fabrics and also leads to pilling which makes fabric appearance and soft­ness worse. However, fuzz on fabric surface is measured mostly by subjective methods (human vision) rather than objective methods. Thus, in this study, objective method using image analysis techniques has been developed for the measurement of fuzz on fabric surface. Fuzz on the fabric has also been ranked and rated by experts in order to see the reliability of the results obtained from the fuzz measurement. It was observed that correlation coefficient (r) between rating value and objective mea­surement value was 0.9 and this correlation coefficient value confirmed the reliability of this method.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
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• pp.499-501
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• 2005

One of representative techniques for compensation of LC's slow response characteristic is the Response Time Acceleration (RTA) technique. The conventional data definition for the RTA is based on the manual measurement and thus it takes long time. Therefore it is almost impossible to use panel specific compensation data in MP line. We have developed a new automated measurement system and flicker minimization for this purpose, which could achieve dramatic measurement time reduction, consistency over different operator, and optimized values as well. This system laid the groundwork for the application of image quality enhancement technologies to panels individually, and using this system, we can expect very uniform image quality for all LCD panels.

• Journal of Information Processing Systems
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• 제19권2호
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• pp.232-239
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• 2023

Aiming at the poor compression quality of traditional image compression coding (ICC) algorithm, a multi-description ICC algorithm based on depth learning is put forward in this study. In this study, first an image compression algorithm was designed based on multi-description coding theory. Image compression samples were collected, and the measurement matrix was calculated. Then, it processed the multi-description ICC sample set by using the convolutional self-coding neural system in depth learning. Compressing the wavelet coefficients after coding and synthesizing the multi-description image band sparse matrix obtained the multi-description ICC sequence. Averaging the multi-description image coding data in accordance with the effective single point's position could finally realize the compression coding of multi-description images. According to experimental results, the designed algorithm consumes less time for image compression, and exhibits better image compression quality and better image reconstruction effect.

• 한국통신학회논문지
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• 제23권4호
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• pp.1066-1071
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• 1998

본 논문은 적응적 영상개선을 위한 전 단계로 자기상관함수를 이용한 지문 영상의 방향성 특성과 화질의 관계 분석에 관한것이다. 이를 위해서 원 영상을 방향 영상으로 변환한 실험영상을 대상으로 부 영역의 크기를 16, 32, 64, 방향성을 1, 2, 3, 4로 설정하고 화질의 척도인 방향성 누적값을 산출하였다. 또한 지문영상에 대한 화질 특성을 추출하고 최적의 부 영역과 방향성 관계를 정량적인 실험 자료로 제시하기위해 군집환 알고리즘을 이용한 분석 과정을 수행하였다.

• 농업과학연구
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• 제37권2호
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• pp.303-308
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• 2010

Surface color is the most important quality factor for the grade evaluation of cherry tomato. Color is one of the representative indicators for the maturity which is closely related to the internal quality of cherry tomato, such as firmness, sugar content, and acidity. This study was carried out to investigate the relationship between surface color and internal quality of cherry tomatoes harvested from both hydroponic and soil culture at different ripening stages. To calculate the color values of cherry tomatoes an automatic color imaging system was constructed. A specially designed image processing algorithm for the color measurement was developed. The color values of L*, a*, b* were calculated from the initial color values of RGB and then compared with the internal quality. Statistical analyses indicated that the internal quality was more highly correlated with the surface color than size of cherry tomatoes. Color image features were also investigated to detect external damage of cherry tomatoes. The value of (R value - R mean value)/R mean value was the most effective image feature for the detection of damaged areas on the surface of cherry tomatoes. The results of this study demonstrated the feasibility of color sorting process as an alternative of the conventional drum type size sorting system for cherry tomato industry.