• Maxillofacial Plastic and Reconstructive Surgery
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• 제28권3호
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• pp.222-228
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• 2006

Various methods have been used in the past to indirectly analyze the craniofacial region. Among these, the lateral and posterior-anterior cephalometircs are used for the evaluation of the dentofacial deformities. However, cephalometircs create inaccuracies because of the inherent enlargement and distortion of the image. The interpretation of cephalometric films is also problematic: the number of anatomic landmarks that can be identified accurately is limited, and the overlap of structures on a radiograph making locating these landmarks difficult. To overcome these problems, computed tomography(CT) has been recommended as an useful modality in the diagnosis, surgical planning, and follow-up of craniofacial anomalies. There is no significant enlargement or distortion of the image, overlap of structure, or tracing error. And the number of anatomic landmarks is vast. The purpose of this study was to examine the orbit and midfacial region using Occlusal Maxillary CT, consisted of slices parallel to the occlusal plane. Based on these CT scan, we provide the data that could be applied to monitor an individual patient's skeletal pattern and the guide to the maxillary osteotomy.

• 대한두개안면성형외과학회지
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• 제22권2호
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• pp.85-92
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• 2021

Background: Patients with secondary deformities associated with unilateral cleft lip and nose might also suffer from nostril stenosis due to a lack of tissue volume in the nostril on the cleft side. Here, we used full-thickness skin grafts (FTSGs) to reduce nostril stenosis and various methods for skin volume augmentation. We compared the changes in the symmetry of both nostrils before and after surgery. Methods: From February 2016 to January 2020, 34 patients underwent secondary cheiloplasty and open rhinoplasty for secondary deformities of the unilateral cleft lip and nose with nostril stenosis. FTSG was used on the nostril floor, nasal columella, and alar inner lining. The measured nasal profile included the nostril surface, nostril circumference, width of the nostril floor, and distance from the alar-facial groove to the nasal tip. The "overlap area," which was defined as the largest overlapping area when the image of the cleft nostril was flipped to the left and right and overlaid on the image of the normal side nostril, was also calculated. The degree of symmetry was evaluated by dividing the value of the cleft side by that of the normal side of each measured profile and expressed as "ratios." Results: The results of all profile ratios, except for the nostril floor width, became significantly close to 1, which represents full symmetry. The overlap area ratio improved from 62.7% to 77.3%, meaning that the length and width of the nostril as well as the overall shape became similar (p< 0.05). Conclusion: When performing cleft rhinoplasty with nostril stenosis, FTSG is useful to achieve symmetry in the nostril size and shape. Skin grafting is simpler to perform than the other types of local flap, and the results are generally satisfactory.

• 한국정보처리학회논문지
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• 제7권6호
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• pp.1834-1843
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• 2000

In this paper, we propose a modular neural network based classification method for handwritten numerals utilizing rotated and translated images of an input image. The whole numeral pattern space is divided into smaller spaces which overlap each other and form multiple clusters. On these multiple clusters, multiple multilayer perceptrons (MLP) neural networks, specialized in those clusters, are constructed. Thus, each MLP acts as an expert network on the corresponding cluster. An MLP is also used as a gating network functioning as a mediator among the multiple MLPs. In the learning phase, an input numeral image is dithered by tow geometric operations of translation and rotation so that new numeral images similar to original one are generated. In the recognition phase, we utilize not only input numeral image, but also nearly generated images through the rotation and the translation of the original image. Thus, multiple output values for those generated images were combined to make class decision by various combination methods. The experimental results confirm the validity of the proposed method.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권12호
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• pp.4866-4888
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• 2020

One major and time-consuming task in fish production is obtaining an accurate estimate of the number of fish produced. In most Nigerian farms, fish counting is performed manually. Digital image processing (DIP) is an inexpensive solution, but its accuracy is affected by noise, overlapping fish, and interfering objects. This study developed a catfish recognition and counting algorithm that introduces detection before counting and consists of six steps: image acquisition, pre-processing, segmentation, feature extraction, recognition, and counting. Images were acquired and pre-processed. The segmentation was performed by applying three methods: image binarization using Otsu thresholding, morphological operations using fill hole, dilation, and opening operations, and boundary segmentation using edge detection. The boundary features were extracted using a chain code algorithm and Fourier descriptors (CH-FD), which were used to train an artificial neural network (ANN) to perform the recognition. The new counting approach, based on the geometry of the fish, was applied to determine the number of fish and was found to be suitable for counting fish of any size and handling overlap. The accuracies of the segmentation algorithm, boundary pixel and Fourier descriptors (BD-FD), and the proposed CH-FD method were 90.34%, 96.6%, and 100% respectively. The proposed counting algorithm demonstrated 100% accuracy.

• 한국측량학회지
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• 제39권2호
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• pp.81-91
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• 2021

Drone related research has been increasing recently due to the development and distribution of commercial unmanned aerial vehicles. However, most of the previous studies focused on the accuracy and utility of drone surveying. For drones, the resolution of the result is determined according to the flight altitude, but since 70% of Korea is mountainous, it is necessary to analyze the quality of the drone image according to the flight plan. In this study, the quality of drone photogrammetry results according to flight plans was analyzed. The flight plan was established by fixed altitude and considering the height of the terrain. Images were acquired for both cases and data was processed to generate ortho images. As a result of evaluating the accuracy of the generated ortho image, the accuracy was found to be -0.07 ~ 0.09m. The accuracy of Case I and Case II did not show a significant difference, but for RMSE, Case I showed a good value. These results indicate that the drone flight plan affects the quality of the results. Also, when flying at a fixed altitude, II showed a lower value than the originally set overlap according to the altitude of the object. In future surveys using drones, flight planning taking into account the height of the object will contribute to the improvement of the quality of the results.

• 정보처리학회논문지B
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• 제9B권4호
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• pp.481-490
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• 2002

오프라인 필기체 문자 인식은 동적인 정보를 가지고 있지 않고, 다양한 필기와 자음과 모음의 겹침이 심하며, 획 사이의 잡영을 많이 가지고 있어 불완전한 전처리를 수행하여야 하는 어려움이 있다. 따라서 오프라인 필기체 문자 인식은 다양한 방법의 전처리 즉 이진화 및 세선화에 대한 연구가 필요하다. 본 논문에서는 오프라인 필기체 한글 문자 인식의 전처리로서 워터쉐드 알고리즘의 수행 시간과 결과 영상의 품질을 고려해 그레이 레벨 문자 영상에서의 문자 영역과 배경 영역의 분할을 위한 효과적인 워터쉐드 알고리즘의 적용 방법과 추출된 워터쉐드 영상을 이진화하는 분할 함수를 제안한다. 또한 수행 시간과 골격선의 품질을 고려한 조건 검사 마스크를 통해서 효과적으로 골격선을 추출하는 세선화 방법을 제안하고 기존의 방법과 본 논문 방법을 수행 시간과 품질로써 성능을 평가한다. 실험 결과 기존의 방법은 평균 2.16초, 본 논문 방법은 평균 1.72초의 수행 시간이 걸렸다. 또한 결과 영상의 품질은 본 논문 방법이 문자 획 사이의 잡영을 효과적으로 처리함을 알 수 있었다.

• 한국방사선학회논문지
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• 제16권2호
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• pp.157-162
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• 2022

전임상용 양전자방출단층촬영기기는 인체에 비해 매우 작은 소동물을 대상으로 촬영이 이루어지므로, 우수한 공간분해능을 지닌 검출기가 필요하다. 이를 위해 작은 섬광 픽셀을 사용한 검출기를 사용하여 시스템을 구성하였다. 현재 개발되어 사용되는 광센서의 크기는 한정되어 있으므로, 이에 맞는 최소한의 섬광 픽셀과 최대의 배열로 구성할 경우 우수한 공간분해능을 얻을 수 있다. 본 연구에서는 광센서의 크기를 고정하고, 이에 맞는 다양한 섬광 픽셀의 배열을 구성하여 평면 영상에서 겹침이 발생하지 않고, 모든 섬광 픽셀들이 구분이 되는 최대의 섬광 픽셀 배열을 찾고자 한다. 이를 위해 섬광체와 광센서로 이루어진 검출기 모듈의 시뮬레이션이 가능한 DETECT2000을 사용하였다. 3 mm × 3 mm 픽셀이 4 × 4 배열로 이루어진 광센서를 사용하였으며, 섬광 픽셀 배열은 8 × 8에서부터 13 × 13까지 구성하여 시뮬레이션을 수행하였다. 광센서 픽셀에서 획득된 데이터를 통해 평면 영상을 구성하였으며, 평면 영상과 프로파일을 통해 영상의 겹침이 발생하지 않는 최대의 섬광 픽셀 배열을 찾았다. 그 결과 평면 영상에서 서로 겹침이 발생하지 않고 모든 섬광 픽셀들이 영상화되는 섬광 픽셀 배열의 크기는 11 × 11이었다.

• 핵의학기술
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• 제28권1호
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• pp.57-69
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• 2024

Purpose: Quantitative analysis through count measurement in nuclear medicine planar images is limited by analysis techniques that are useful for obtaining various clinical information or by organ overlap or artifacts in actual clinical practice. On the other hand, the use of SPECT tomography images is quantitative analysis using volume rather than planar, which is not only free from problems such as projection overlap, but also has excellent quantitative accuracy. In the use of developing SPECT quantitative analysis technology, this study aims to compare the accuracy of quantitative analysis between ROI of the conventional planar images and VOI of the SPECT tomographic images in evaluating the count change happened by the volume change of the source. Materials and Methods: A ^99mTcO₄^- source(200.17 MBq) was filled with sterilized water in the syringe to create a phantom with an inner diameter volume of 60 cc, and a planar image and a SPECT image were obtained by reducing the volume by 15 cc (25%) respectively. ROI and VOI(threshold: 1~45%, 5% interval) were set for each image obtained to estimate true count and measure the total count, and compared with the preseted volumetric change rate(%). Results: When volume changes of 25%, 50%, and 75% occurred in the initial volume of 60 cc(100%) of the phantom, the average count changes of the measured planar image were 26.8%, 53.2%, 77.5%, and the average count changes of the SPECT image were 24.4%, 50.9%, and 76.8%. In this case, the VOI size(cm³) set showed an average change rate of 25.4%, 51.1%, and 76.6%. The highest threshold value for the accuracy of radioactive concentration by VOI size (average error -1.03%) was 35%, and the VOI size of the same threshold had an error of -17.1% on average compared to the actual volume. Conclusion: On average, the count-based volumetric change rate in nuclear medicine images was able to track changes more accurately using VOI than ROI, but there was no significant difference with relatively similar value. However, the accuracy of radioactive concentration according to individual VOI sizes did not match, but it is considered that a relatively accurate quantitative analysis can be expected when the size of VOI is set smaller than the actual volume.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2004년도 추계학술발표회 논문집
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• pp.519-522
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• 2004

The purpose of this research is to design a road using digital photogrammatry method to generate DEM(digital elevation model) and digital ortho image based on GSIS which was applied to the road simulation. The example study area was the suburbs of Jeju city. To this study, 1/5,000 digital map and GSIS technique were used for optimum road design of the island based on Arc View software. Using this software we can Set an overlay map by combination of hill shade map, slope map, aspect map, and building buffer map. Based on this overlap map, we designed the best road line and along this line we performed three dimensional road simulation using Microstation CAD and Inroads road design programs. From the results, we found that the DEM and digital ortho image acquired from stereoairphoto using digital photogrammatry was satisfied for choosing the best roadline and the developed three dimensional road simulation technique using GSIS technique was very useful to estimate the reasonable road design before the real road construction works.

• 제어로봇시스템학회논문지
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• 제16권1호
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• pp.40-47
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• 2010

This paper presents a simultaneous localization and mapping (SLAM) of an indoor hallway environment using Rao-Blackwellized particle filter (RBPF) along with a line segment as a landmark. Based on the fact that fluent line features can be extracted around the ceiling and side walls of hallway using vision sensor, a horizontal line segment is extracted from an edge image using Hough transform and is also tracked continuously by an optical flow method. A successive observation of a line segment gives initial state of the line in 3D space. For data association, registered feature and observed feature are matched in image space through a degree of overlap, an orientation of line, and a distance between two lines. Experiments show that a compact environmental map can be constructed with small number of horizontal line features in real-time.