• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.568-571
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• 1997

Recently, the number of techniques for analyzing medical images has been increasing in computer vision, employing X-ray CT images, ultrasound images, MR images, moire topographic images, etc. Spinal deformity is a serious problem especially for teenagers and medical doctors inspect moire topographic images of their backs visually for the primary screening. If a subject is normal, the moire image is almost symmetric with respect to the middle line of the subject's back, otherwise it shows asymmetric shape. In this paper, an image analysis technique is described for discriminating suspicious cases from normal in human spinal deformity by recognizing asymmetric moire images of human backs. The principal axes which are sensitive to asymmetry of the moire image are extracted at two parts on a subject's back and their angles are evaluated with respect to the detected middle line of the back. The two angles compose a 2-D feature space and inspected cases are divided into two clusters in the space by a linear discriminant function based on the Mahalanobis distance. Given 120 cases, 60 normal and 60 abnormal, the leave-out method was applied for the recognition and 75% recognition rate was achieved.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1995년도 Proceedings of the Korea Automation Control Conference, 10th (KACC); Seoul, Korea; 23-25 Oct. 1995
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• pp.244-247
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• 1995

A technique is presented for evaluating spinal deformity of a human back by extracting a spinal line based on 3-D topograpic reconstruction of the back from its moire image. A given moire image is differentiatedby DOG filter to extract moire stripes. The stripes are then assigned labels and the labels are interpolated by the Lagrange polynomial to yield the undulation of the back which gives a relative 3-D shape of the back. A valley is searched on the undulation near the middle part of the back and the valley line is finally extracted as an approximated spinal line. The mean differenceand the variance between the spinal line and the middle line are calculated and reported. Experiment is performed employing real moire images ofjunior-high school students' backs and some of the results are shown with discussion.

• 대한방사선기술학회지:방사선기술과학
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• 제40권4호
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• pp.575-580
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• 2017

Moire artifact는 미세병변과 주파수 대역이 중첩되기 때문에 moire artifact를 제거하는 Image processing software를 사용할 경우 미세 병변의 손실을 가져올 수 있다. 본 연구에서는 SD(Sprague Dawley) Rat에 microcalcification과 microfracture와 같은 미세병변을 임의로 형성하여 영상화하고, reference 영상과 grid suppression software를 사용한 영상, optimizied grid 영상을 비교 분석하였다. 영상은 두 명의 영상의학과 전문의가 컨소시엄을 형성하여 판독하였고, 판독 결과 값은 McNemar's test 이용하여 평가하였다. 73개의 microcalcifications 중 Grid suppression후 13 cases에서, optimized grid를 사용한 영상은 3 cases에서 영상의 손실이 확인되어 Grid suppression후의 영상이 통계적으로 유의하게 영상 손실을 발생하고 있음을 보여주고 있다(p=0.021). 총 53개의 fracture line은 Grid suppression을 시행한 후 영상에서 19 cases가 영상의 손실을 보였고, optimized grid를 사용한 영상에서는 영상손실이 없는 것으로 판독되었다. 따라서 미세병변을 진단하는 영상에 있어 moire artifact를 제거하기 위한 grid suppression software 사용은 신중하게 고려되어야 할 것이다.

• 방송공학회논문지
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• 제26권1호
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• pp.3-13
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• 2021

본 논문은 다중 도메인 학습을 이용하여 화면 촬영 영상 내 모아레 무늬를 효과적으로 제거하는 기법을 제안한다. 제안하는 기법은 먼저 화소값 영역과 주파수 영역에서 입력 영상의 모아레 무늬를 각각 제거한다. 다음으로 모아레 영상에서 clean edge map을 추정하고, 추정된 clean edge map을 가이드 정보로 사용하여 화소값 영역과 주파수 영역에서 얻은 결과 영상의 품질을 향상시킨다. 마지막으로, 독립적으로 향상된 두 결과 영상을 적응적으로 결합하며 모아레 무늬가 제거된 최종 결과 영상을 생성한다. 컴퓨터 모의 실험결과를 통해 제안하는 기법이 기존의 알고리즘보다 모아레 무늬를 더욱 효과적으로 제거할 수 있음을 확인한다.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 1999년도 학술대회
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• pp.47-52
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• 1999

복잡한 모델이나 사실적인 모델을 짧은시간에 생성하기 위해서 기존 자유곡면(NURBS)이나 다각형(Polygon) 모델러를 사용하여 제작하는데 한계가 있다. 또한, 최근디지털 컨텐츠 산업의 급격한 발전과 컴퓨터 그래픽스 기술의 발전과 함께 삼차원 스캐너를 이용한 모델생성이 중요한 연구분야로 자리잡고 있다. 이 논문에서는 국내 최초로 한국 전자통신연구원이 개발에 성공한 모아레 방식의 삼차원 스캐너 시스템(RTRI Moire Scanner)의 삼차원 입체정보 처리 소프트웨어인Moireware의 설계 및 구현에 대해 설명하려고 한다. 본 시스템은 스캐너에서 얻어진다면 데이터 및 텍스췌 정보의 효율적인 정합, 가공, 편집 및 다양한 3차원 그래픽 파일 포맷을 제공한다.

• 한국인쇄학회지
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• 제15권2호
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• pp.57-76
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• 1997

A color halftoning is the process of generating halftone images for the different color plans, for example, cyan, magenta, yellow, and black for a offset printing device. A conventional halftone technique, so called AM screening, is simple and easy to implement, but the halftoned dot patterns by using this method is not free for the moire` fringe. Moire` patterns are caused the power spectrum distribution on low spatial frequency domain. To avoid Moire` patterns, the conventional screen require the different screen angles for each color plans. Recently, Ultra-fine and 7 color printing methods are developed to expend the color gamut. In 7 color printing method must be used the halftone technique of random and blue noise characteristic to avoid Moire` fringe.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.105.1-105
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• 2001

In this paper, a technique is described for classifying normal cases and abnormal cases in automatic spinal deformity detection by computer based on moire topographic images of human backs. Displacement is evaluated statistically between the middle line extracted from the entire moire image and the middle line obtained from a small rectangle area defined on the moire image. The middle line is calculated employing a developed potential symmetry analysis technique. The displacement is calculated in several regions and the mean and the standard deviation of the displacement values are chosen as two features. A linear discriminant function (LDF) is defined on the 2-D feature space based on the Mahalanobis distance and the features are classified into two categories, i.e., normal and ...

• 대한방사선기술학회지:방사선기술과학
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• 제41권2호
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• pp.149-155
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• 2018

Quantitative analysis was performed to confirm that moire artifact was removed without loss of image when using grid suppression software in the diagnosis of micro lesions. we showed that grid suppression images can be morphologically different from original images as they are significantly lower than those of the optimized grid in the similarity analysis with reference images in mammographic phantom images. We were confirmed that images of microcalcification with smaller signal than noise were lost because the pixel values of all lesions increased significantly after the grid suppression, The change in contrast using the NORMI 13 X-ray test phantom was reduced to 30% of the reference image, This result was significantly lower than the 90% when using the optimized grid. In conclusion, the use of grid suppression software in clinical images should be carefully considered because of the possibility of misdiagnosis due to micro lesion loss and morphological changes.

• 한국전기전자재료학회논문지
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• 제16권12S호
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• pp.1261-1267
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• 2003

Since the grating optical low-pass fillet degrades the resolution of images, we developed a hologram optical low-pass filter that show low degradation of the image and studied its characteristics. We designed the hologram that divides input beam into circular shaped 21 beams with a Monte-Carlo based hologram generation program and calculated its MTE characteristics to compare it with that of a grating filter. The hologram was manufactured through the optical lithography process and attached to a digital imaging device (Zoran 732212) for measurement. The moirfiltering is compared with zone plate images and the resolution loss is measured with USAF resolution chart. The hologram optical low-pass filter showed better characteristics in both moly filtering and resolution.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 Proceedings of the Korea Automatic Control Conference, 11th (KACC); Pohang, Korea; 24-26 Oct. 1996
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• pp.438-441
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• 1996

Spinal deformity is a serious disease especially for teenagers and it is desirable for school children to be checked possible spinal deformity by moire photographic inspection method. The moire images of children's backs are visually inspected by doctors, which may cause misjudge because of a large amount of data they have to examine. A technique is proposed in this paper for automating this inspection by computer. Two characteristic axes, a potential symmetry axis approximating the human middle line and a principal axis representing the direction of a moire pattern are employed. Two principal axes are extracted locally on a back and their gradients against the potential symmetry axis are calculated. These gradients compose a 2D feature space and a linear discriminant function (LDF) is defined there which separates normal cases from suspicious cases. The LDF defined by 40 training, data was employed in the experiment to examine 40 test data and 77.5% of them were classified correctly. This amounts to 88.8% if the training data is included.