• 대한치과교정학회지
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• 제41권4호
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• pp.255-267
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• 2011

본 연구에서는 cone beam computed tomography (CBCT)를 이용한 삼차원 영상을 기준으로 CBCT-재구성 파노라마영상 형성 시의 신뢰성을 입증하고 CBCT 삼차원 영상과 비교하여 실제 근원심 치축을 가장 잘 나타낼 수 있는 이차원 파노라마영상을 찾고자 하였다. 연구 모형은 두부계측방사선사진의 평균치에 따라 제작되었고 CBCT와 파노라마방사선영상 촬영을 위해 촬영 시마다 연구 모형이 반복적으로 재위치되었다. 파노라마방사선영상은 $-5^{\circ}$, $0^{\circ}$, $+5^{\circ}$로 연구 모형의 교합평면을 변화시키면서 촬영되었다. 이후 CBCT 삼차원 영상과 CBCT-재구성 파노라마영상 및 파노라마방사선영상에서 측정된 계측값을 평가하였다. CBCT 삼차원 영상과 CBCT-재구성 파노라마영상의 전치 및 견치부에서 통계학적으로 유의성 있는 차이를 나타내지 않았으나 대부분의 소구치부에서는 통계학적으로 유의성 있는 차이를 나타내었다. 그리고 CBCT-재구성 파노라마영상과 파노라마방사선영상은 대부분의 치아에서 통계학적으로 유의성 있는 차이를 나타내었다. CBCT-재구성 파노라마영상이 근원심 치축 평가 시 임상적으로 사용 가능함을 보여주었다.

• 대한치과의사협회지
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• 제57권1호
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• pp.26-33
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• 2018

Panoramic radiography is widely used as a primary radiological diagnosis in dentistry. However, due to the overlapping of anatomical structures, diagnostic capability of panoramic radiography is limited. Recently, panoramic machine equipped with various image processing software has been introduced to improve the diagnostic capability. This study aims to introduce panoramic equipment with multi-layer imaging software that can provide 41 images from anterior to posterior in region of interest, and to report in various clinical applications.

• Imaging Science in Dentistry
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• 제42권3호
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• pp.183-190
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• 2012

Purpose: The purpose of this study was to investigate the level of clinical image quality of panoramic radiographs and to analyze the parameters that influence the overall image quality. Materials and Methods: Korean dental clinics were asked to provide three randomly selected panoramic radiographs. An oral and maxillofacial radiology specialist evaluated those images using our self-developed Clinical Image Quality Evaluation Chart. Three evaluators classified the overall image quality of the panoramic radiographs and evaluated the causes of imaging errors. Results: A total of 297 panoramic radiographs were collected from 99 dental hospitals and clinics. The mean of the scores according to the Clinical Image Quality Evaluation Chart was 79.9. In the classification of the overall image quality, 17 images were deemed 'optimal for obtaining diagnostic information,' 153 were 'adequate for diagnosis,' 109 were 'poor but diagnosable,' and nine were 'unrecognizable and too poor for diagnosis'. The results of the analysis of the causes of the errors in all the images are as follows: 139 errors in the positioning, 135 in the processing, 50 from the radiographic unit, and 13 due to anatomic abnormality. Conclusion: Panoramic radiographs taken at local dental clinics generally have a normal or higher-level image quality. Principal factors affecting image quality were positioning of the patient and image density, sharpness, and contrast. Therefore, when images are taken, the patient position should be adjusted with great care. Also, standardizing objective criteria of image density, sharpness, and contrast is required to evaluate image quality effectively.

• Transactions on Electrical and Electronic Materials
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• 제18권5호
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• pp.273-278
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• 2017

Recently, one of the areas where research is being actively conducted is the Internet of Things (IoT). The field of using the Internet of Things system is increasing, coupled with a remarkable increase of the use of the camera. However, general cameras used in the Internet of Things have limited viewing angles as compared to those available to the human eye. Also, cameras restrict observation of objects and the performance of observation. Therefore, in this paper, we propose a panoramic image stitching method using feature extraction and matching based on an embedded system. After extracting the feature of the image, the speed of image stitching is improved by reducing the amount of computation using the necessary information so that it can be used in the embedded system. Experimental results show that it is possible to improve the speed of feature matching and panoramic image stitching while generating a smooth image.

• Imaging Science in Dentistry
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• 제44권1호
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• pp.1-6
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• 2014

Professionals performing radiographic examinations are responsible for maintaining optimal image quality for accurate diagnoses. These professionals must competently execute techniques such as film manipulation and processing to minimize patient exposure to radiation. Improper performance by the professional and/or patient may result in a radiographic image of unsatisfactory quality that can also lead to a misdiagnosis and the development of an inadequate treatment plan. Currently, the most commonly performed extraoral examination is panoramic radiography. The invention of panoramic radiography has resulted in improvements in image quality with decreased exposure to radiation and at a low cost. However, this technique requires careful, accurate positioning of the patient's teeth and surrounding maxillofacial bone structure within the focal trough. Therefore, we reviewed the literature for the most common types of positioning errors in panoramic radiography to suggest the correct techniques. We would also discuss how to determine if the most common positioning errors occurred in panoramic radiography, such as in the positioning of the patient's head, tongue, chin, or body.

• 인터넷정보학회논문지
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• 제18권5호
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• pp.79-85
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• 2017

본 논문은 모바일 스마트 단말에서 파노라마 이미지 생성 프로세스를 단축하기 위해 모바일 애드혹 클라우드를 활용하는 방법을 제시한다. 파노라마 이미지 생성과 관련된 작업을 효율적으로 모바일 애드혹 클라우드에 분배하기 위해 이미지 획득 및 정렬 방법을 제안하고 작업분배에 대한 오프로딩 결정 알고리즘을 제안한다. 제안된 방법을 안드로이드 운영체제 기반의 모바일 스마트 단말에 직접 적용하여 파노라마 이미지 생성 프로세스에 미치는 영향을 분석한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권11호
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• pp.5419-5435
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• 2017

The construction of panoramic images on smartphones and low-powered devices is a challenging task. In this paper, we propose a new approach for smoothly stitching images on mobile phones in the presence of moving objects in the scene. Our main contributions include handling moving object problems, reducing processing time, and generating rectangular panoramic images. First, unique and robust feature points are extracted using fast ORB method and a feature matching technique is applied to match the extracted feature points. After obtaining good matched feature points, we employ the non-deterministic RANSAC algorithm to discard wrong matches, and the hommography transformation matrix parameters are estimated with the algorithm. Afterward, we determine precise overlap regions of neighboring images and calculate their absolute differences. Then, thresholding operation and noise removal filtering are applied to create a mask of possible moving object regions. Sequentially, an optimal seam is estimated using dynamic programming algorithm, and a combination of linear blending with the mask information is applied to avoid seam transition and ghosting artifacts. Finally, image-cropping operation is utilized to obtain a rectangular boundary image from the stitched image. Experiments demonstrate that our method is able to produce panoramic images quickly despite the existence of moving objects.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제33권5호
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• pp.504-510
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• 2007

Purpose: The purpose of this study was to determine the incidence of antral septa and the accuracy of panoramic radiograph in identifying maxillary sinus septa. In addition, when panoramic radiograph led to a false diagnosis of more than majority, we analyzed findings of the panoramic radiograph. Patients and methods: This study included 180 patients who were radiographically examined before the surgery was done using both panoramic and computerized tomographic radiographs(CT scan), Samsung Medical Center from April 2003 to March 2006, and examined the incidence of antral septa, the false diagnosis rate of panoramic radiograph, and radiographic characters in case of false diagnosis. Only those bone lamellae were considered as septa that showed a height of at least 3.0mm. It was thus possible to exclude the alveolar recess. One oral and maxillofacial surgeon(OMFS) determined the presence or absence of sinus septa in CT scan, and five OMFS determined the presence or absence of sinus septa in panoramic radiograph. Results: The septa were observed in 81 of 360 sinuses(22.5%). All septa were oriented in a buccopalatal plane. More or less greater prevalence was observed in the second molar region(38.2%) but no predominant location was found. Panoramic radiograph led to false diagnosed septa in 361 of 1800 cases(20.1%). In case of false diagnosis of more than majority, superimposed image on zygomatic process was 44.1%, faint image in the region not related to sinus lifting 26.5%, faint image in the region related to sinus lifting 17.6%, and misconception for superimposed image 11.8% Conclusion: In this study we could get clinico-anatomical information of septum in the maxillary sinus. Compared to CT scan, panoramic radiograph can not clearly differentiate the sinus septa, but we consider that panoramic radiograph may improve its usefulness if we take additional modified panoramic radiograph and clinical exam.

• 융합신호처리학회논문지
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• 제12권1호
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• pp.26-32
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• 2011

This paper proposes a new method to process panoramic image stitching using SURF(Speeded Up Robust Features). Panoramic image stitching is considered a problem of the correspondence matching. In computer vision, it is difficult to find corresponding points in variable environment where a scale, rotation, view point and illumination are changed. However, SURF algorithm have been widely used to solve the problem of the correspondence matching because it is faster than SIFT(Scale Invariant Feature Transform). In this work, we also describe an efficient approach to decreasing computation time through the homography estimation using RANSAC(random sample consensus). RANSAC is a robust estimation procedure that uses a minimal set of randomly sampled correspondences to estimate image transformation parameters. Experimental results show that our method is robust to rotation, zoom, Gaussian noise and illumination change of the input images and computation time is greatly reduced.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.49.6-49
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• 2001

This paper describes a self-localization method for the mobile robot using panoramic view images. A panoramic view image has the information of location of the objects from the viewer robot and direction between the objects at a position. Among the sequence of panoramic view images, the target objects in the image like traffic signs, facade of a building, road signs, etc. locate in the real world so that robot´s position and direction deliver to localize from his view. With the previously captured panoramic images, the method calculates the distance and direction of the region of interest, corresponds the regions between the sequences, and identifies the location in the world. To obtain the region, vertical edge line segments