• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.6
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• pp.99-104
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• 2021

The technology of estimating a movement trajectory using a monocular camera such as a smartphone and composing a surrounding 3D image is key not only in indoor positioning but also in the metaverse service. The most important thing in this technique is to estimate the coordinates of the moving camera center. In this paper, a new algorithm for geometrically estimating the moving distance is proposed. The coordinates of the 3D object point are obtained from the first and second photos, and the movement distance vector is obtained using the matching feature points of the first and third photos. Then, while moving the coordinates of the origin of the third camera, a position where the 3D object point and the feature point of the third picture coincide is obtained. Its possibility and accuracy were verified by applying it to actual continuous image data.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.425-428
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• 2004

본 논문에서는 시간영역에서 해양 음 전달 해석을 위해 엇갈림 격자에서 유사 스펙트럴 알고리듬을 기반으로 한 전산조직을 개발하였다. 유사 스펙트럴 방법은 파수 영역에서 파수에 음압의 푸리에 변환을 곱한 후 이를 역 푸리에 변환함으로서 공간 도함수를 구하는 방법이다. 유사 스펙트럴 방법은 빠른 푸리에 변환법의 사용으로 계산속도가 빠르며, 엇갈림 격자에서 이 방법을 사용하면 음 전달 현상을 정확하고 안정되게 모사할 수 있다. 무한 및 반무한 영역에서 이 알고리듬에 의한 결과가 해석해와 잘 일치함을 확인하였고, 다양한 해양환경에서 시간영역 모델링을 수행하여 스냅사진을 얻어내었으며 이 스냅사진을 통해 복잡한 해양환경에서 신호의 전파 현상을 파악할 수 있었다.

• Proceedings of the KOSOMBE Conference
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• v.1994 no.05
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• pp.19-22
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• 1994

심장과 혈관의 고해상도 영상을 얻어 심질환에 관한 정보를 얻는데는 혈관조영기(Angiograph)가 가장 유용하게 사용되고 있다. 본 연구는 혈관조영기의 정량분석을 위한 영상 알고리즘을 구현하였다. 심장의 수축 이완에 따른 심벽의 부위별 움직임과 심장 체적 변화를 측정 수치화하고 혈관을 따라가면서 혈관의 두께를 기록하는 프로그램을 작성하였다. 영상획득과정에서 생기는 잡음과 위치오차를 없애는 전처리를 거친 후에 구조적 형태 인식법(Structural Pattern Recognition)으로 인식 알고리즘을 구현하였다. 14장의 심장의 수축이완 연속사진과 2장의 관상동맥 혈관조영사진을 분석한 결과 비교적 정확한 측정을 해내는 것을 관찰할 수 있었다.

• Korean Journal of Cognitive Science
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• v.2 no.2
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• pp.359-403
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• 1990

This paper introduces a blackboard system which extracts imbedded road and building structures irom aerial photograph images. The role of three major component(blackboard, knowledge source, and control module)in blackboard system will be illustrated in terms of knowledge representation and control strategies. The hypothesis on a blackboard will be organized in a hierarchical form, the knowledge sources which generate hypothesis and verify them will be shown in detail, and the control module will describe how the knowledge sources can dervie solutions. Especially this paper shows that searching image strutures can be greatly simplified by the use of a mapping image.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.11a
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• pp.88-89
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• 2014

A vector-photo is a photography which contain image and 5W1H information. Objects pictured and an image in a vector-photo can be linked by 5W1H information in the vector-photo. This study discuss a positioning module to link between vector-photos and 3D BIM model. The module developed in this study can be utilized in a system that can link the vector-photos with objects in BIM model.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.11a
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• pp.118-119
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• 2013

Many pictures are taken in construction sites. However, the pictures are not being managed effectively. In this study, the need for vector-photo have been raised which combines pictures and 5W1H information, and the vector-photo format have been suggested. A test module and user-interface have been developed for validating an utility of the format proposed.

• Proceedings of the Korea Information Processing Society Conference
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• 2006.11a
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• pp.109-112
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• 2006

이미지 모자이크 기법은 한 번에 촬영 할 수 없는 큰 배경이나 사물을 부분적으로 촬영 한 후 이들을 조합하여 전체 배경이나 사물을 합성하는 기술이다. 이 기술은 주로 지형을 촬영한 항공사진을 조합하여 전체 영상을 얻는 용도로 사용되어왔다. 본 연구에서는 일반적인 스틸사진의 조합이 아닌 동영상으로 촬영된 영상물로부터 전체 배경을 합성하는 방법에 대한 것이다. 이를 위하여 먼저 비디오 프레임간의 공통적인 특징 점들을 추출하고 일치되는 점들을 찾아내었다. 이로부터 두 프레임간의 상대적인 좌표를 구한 후 이를 저장하였다. 마지막으로 합성 단계에서는 저장된 상대 좌표로부터 부분 이미지를 연결하여 전체 이미지를 구하는 방법을 제안하였다. 제안된 방법은 근접 촬영이 필수인 협소공간의 고대 구조물의 육안 검사를 소형로봇 등의 원격 이동체에 실린 카메라로 수행하기 위한 용도에 응용될 수 있다.

• KIPS Transactions on Software and Data Engineering
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• v.3 no.8
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• pp.309-314
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• 2014

To generate a complete 3D model from depth images of multiple RGB-D cameras, it is necessary to find 3D transformations between RGB-D cameras. This paper proposes a convenient view calibration technique using a spherical object. Conventional view calibration methods use either planar checkerboards or 3D objects with coded-pattern. In these conventional methods, detection and matching of pattern features and codes takes a significant time. In this paper, we propose a convenient view calibration method using both 3D depth and 2D texture images of a spherical object simultaneously. First, while moving the spherical object freely in the modeling space, depth and texture images of the object are acquired from all RGB-D camera simultaneously. Then, the external parameters of each RGB-D camera is calibrated so that the coordinates of the sphere center coincide in the world coordinate system.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.4
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• pp.721-728
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• 2004

Velopharyngeal closure is a sphincter mechanism between the activities of the soft palate, lateral pharyngeal wall and the posterior pharyngeal wall, which divides the oral and nasal cavity. It participates in physiological activities such as swallowing, breathing and speech. It is called a velopharyngeal dysfunction when this mechanism malfunctions. The causes of this dysfunction are defects in (1) length, function, posture of the soft palate, (2) depth and width of the nasopharynx and (3) activity of the posterior and lateral pharyngeal wall. The purposes of this study are to analyze the nasopharynx of cleft palate patients using cephalometry and to evaluate the degree of hypernasality using nasometry to find its relationship with velopharyngeal dysfunction. The following results were obtained : 1. In cephalometry, there were significant differences in soft palate length, soft palate thickness, nasopharyngeal depth, nasopharyngeal area, and adequate ratio between two groups. 2. In nasometry, there were significant differences between two groups in vowel /o/ and sentences including oral consonants. 3. In cleft palate patients, though no general correlation was found between Anatomic VPI and nasalance scores, vowel /i/ and sentences including oral consonants were slightly correlated. In conclusion, cephalometry and nasometer results were significantly different between the two groups. Though in the cleft palate group, Anatomic VPI and nasalance scores, which are indices for velopharyngeal closure, excluding the vowel /i/ and sentences including oral consonants show generally no significance.

• The korean journal of orthodontics
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• v.37 no.6
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• pp.391-399
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• 2007

Three-dimensional approaches for the diagnosis and analysis of the dentofacial area are becoming more popular in accordance with the development of cone-beam CT (CBCT). The purposes of this study were to evaluate the reliability of cephalometric measurements of lateral cephalograms generated from a CBCT image by making comparisons with the traditional digital lateral cephalogram, and to evaluate the possibility of the clinical application of CBCT generated cephalogram images. Methods: Twenty patients whose external auditory meatus could be identified in the CBCT image were selected, and both CBCT and digital cephalograms were taken. Differences between the measurements of both cephalograms were tested by paired t-test. Results: Among the 22 measurements used, only U1-FH, Mx6 to PTV, and maxillomandibular difference showed statistically significant differences between the CBCT generated cephalogram and the digital cephalogram. Conclusions: The results suggest that the CBCT generated cephalogram can be used for some cephalometric measurements not requiring porion, PTV, condylion as a landmark (SNA, SNB, U1 to SN, IMPA, interincisal angle, etc.).