• Imaging Science in Dentistry
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• 제43권3호
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• pp.185-190
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• 2013

Purpose: The aim of the present study was to evaluate the measurement accuracy of endodontic file length on periapical digital radiography after application of noise reduction digital enhancement. Materials and Methods: Thirty-five human single-rooted permanent teeth with canals measuring 20-24 mm in length were selected. ISO #08 endodontic files were placed in the root canals of the teeth. The file lengths were measured with a digital caliper as the standard value. Standard periapical digital images were obtained using the Digora digital radiographic system and a dental X-ray unit. In order to produce the enhanced images, the noise reduction option was applied. Two blinded radiologists measured the file lengths on the original and enhanced images. The measurements were compared by repeated measures ANOVA and the Bonferroni test (${\alpha}=0.05$). Results: Both the original and enhanced digital images provided significantly longer measurements compared with the standard value (P<0.05). There were no significant differences between the measurement accuracy of the original and enhanced images (P>0.05). Conclusion: Noise reduction digital enhancement did not influence the measurement accuracy of the length of the thin endodontic files on the digital periapical radiographs despite the fact that noise reduction could result in the elimination of fine details of the images.

• 한국광학회:학술대회논문집
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• 한국광학회 2009년도 동계학술발표회 논문집
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• pp.263-264
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• 2009

We propose a method synthesizing elemental images and sub-images for the integral imaging using phase-shifting digital holography. From acquired single 4-step phase-shifting digital holography, we can generate elemental images and sub-images for any lens array specifications.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.182-182
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• 2003

Generally, DEM (Digital Elevation Model) is generated by stereo-images acquired same conditions, sensor type, viewing angle, capturing elevation and etc. It is difficult to generate DEM with stereo images acquired different satellite. This study intends that it is DEM generation using pair-images with other sensor systems.

• Imaging Science in Dentistry
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• 제34권4호
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• pp.185-190
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• 2004

Purpose: To compare the diagnostic accuracy for the detection of root fractures in CMOS-based digital periapical images with conventional film-based periapical images. Materials and Methods: Sixty extracted single-root human teeth with closed apices were prepared endodontically and divided into two groups; artificially induced vertical root fracture group and control group. All radiographs were obtained using the paralleling technique. The radiographs were examined by 4 observers three times within a 4 week interval. Receiver operating characteristic (ROC) analysis was carried out using data obtained from four observers. Intra- and inter-examiner agreements were computed using kappa analysis. Results: The area under the ROC curve (Az) was used as an indicator of the diagnostic accuracy of the imaging system. Az values were as follows: direct-digital images; 0.93, film-based images; 0.92, and inverted digital images; 0.91. There was no significant difference between imaging modalities (P<0.05). The kappa value of inter-observer agreement was 0.42 (range: 0.28-0.60) and intra-observer agreement was 0.57 (range: 0.44-0.75). Conclusion : There is no statistical difference in diagnostic accuracy for the detection of vertical root fractures between digital periapical images and conventional periapical images. The results indicate that the CMOS sensor is a good image detector for the evaluation of vertical root fractures.

• Korean Journal of Mathematics
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• 제31권1호
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• pp.1-16
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• 2023

In this paper, we examine the relations of two closely related concepts, the digital Lusternik-Schnirelmann category and the digital higher topological complexity, with each other in digital images. For some certain digital images, we introduce κ-topological groups in the digital topological manner for having stronger ideas about the digital higher topological complexity. Our aim is to improve the understanding of the digital higher topological complexity. We present examples and counterexamples for κ-topological groups.

• 한국콘텐츠학회논문지
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• 제19권1호
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• pp.117-124
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• 2019

이 논문은 디지털 테크놀러지가 영화 이미지의 미학적 존재론을 어떻게 변화시키고 있는지에 대해 다룬다. 영화 예술의 물질적 기초로서 셀룰로이드 필름을 통한 이미지 생산과 소비의 시대는 이미 막을 내렸다. 컴퓨터와 인터넷 시대의 도래는 영화의 세계에 새로운 이미지 존재론의 출현을 불가피하게 만든다. 오늘날 디지털 시네마 시대에 벤야민의 기계 복제 개념을 재해석할 필요가 있다. 필름 이미지의 기계 복제는 컴퓨터 시뮬레이션에 기초한 디지털 합성 개념으로 변형된다. 또한, 디지털 테크놀러지는 영화의 몽타주 미학에 중대한 변화를 초래한다. 쇼트들의 시간적 연결에 기초한 필름의 몽타주 미학은 컴퓨터 데이터와 픽셀 이미지의 공간적 시뮬레이션에 기초한 '디지털 꼴라주' 미학으로 변화한다. 이 논문은 영화적 환영과 표현의 미학이 확장되는 디지털 하이브리드 이미지 존재론을 탐구함으로써 기존 연구와의 차별성을 제시한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.572-576
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• 1997

X-ray laminography and DT(digital tomosynthesis) that can form a cross-sectional image of 3-D objects promise to be good solutions for inspecting interior defects of industrial products. The major factors of the digital tomosynthesis that influence on the quality of x-ray cross-sectional images are also discussed. The quality of images acquired from the DT system varies according to image synthesizing methods, the number of images used in image synthesizing, and X-ray projection angles. In this paper, a new image synthesizing method named 'log-root method' is proposed to get clear and accurate cross-sectional images, which can reduce both artifact and blurring generated by materials out of focal plane. To evaluate the quality of cross-sectional images, two evaluating criteria: (1) shape accuracy and (2) clearness in the cross-sectional image are defined. Based on this criteria, a series of simulations were performed, and the results show the superiority of the new synthesizing method over the existing ones such as averaging and minimum method.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.523-528
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• 2002

Topology optimization is widely accepted as a conceptual design tool for the product design. Since the resulted layout of the topology optimization is a kind of digital images represented by the density distribution, the seamless process is required to transform digital images to the CAD model for the practical use. In this paper, the general process to construct a CAD model is developed to apply for topology images based on elements. The node density and the morphology technique is adopted to extract boundary contour of the shape and remove the noise of images through erosion and dilation operation. The proposed method automatically generates point data sets of the geometric model. The process is integrated with Pro/Engineer, so that the engineer in practice can directly handle with curves or surface form digital images.

• 감성과학
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• 제10권4호
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• pp.631-637
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• 2007

이미지의 유사성을 결정하는 요인을 톤(tone), 즉 명도와 채도로 결정하여 정보 엔트로피를 계산하여 상관 계수를 계산하였다. 이미지의 톤을 알아보기 위해 영상정보의 색 공간을 RGB color space에서 HSI color space로 전환하였다. 이후 유사성을 판단하기 위해 이미지의 전체 픽셀수가 아닌 엔트로피 값의 범위에 따라 전체 70%의 픽셀 또는 이미지를 가장 많이 구성하는 세 가지 톤의 픽셀 수에 의해 결정되었다. 'Romantic'이라는 인간의 감성으로 판단된 18개의 영상정보를 선정하여 위의 모델을 적용, 이미지 유사성을 판단하였다.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2003년도 춘계학술발표회 논문집
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• pp.321-326
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• 2003

The subjects of this study are to examine and to apply the methods of making 1:5,000 scale maps using 1m resolution stereo images of IKONOS for the Munsan area of Paju-city where aerial photo surveying cannot possible because of security conditions. GCP(Ground Control Point) were acquired from GPS surveying and were to perform geometric corrections on images. Digital Map used IKONOS stereo images and it worked from the digital analytical stereoplotter. From field investigation, RMSE errors of the plane and vertical positions are estimated to 1.706m and 1.231m, respectively. The plane accuracy is better than an accuracy required by NGIS (national GIS) programs. Local information from field investigation was added and the resulting maps should be good as digital map under the scale of 1/5,000.