• 한국정보과학회논문지:소프트웨어및응용
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• 제37권2호
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• pp.110-119
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• 2010

본 논문에서는 MR 영상에서 밝기값 분포와 기울기 정보를 이용한 전립선 자동 분할 기법을 제안한다. 첫째, 적응적 밝기값 프로파일과 다해상도 기법을 이용하는 활성형상모델을 통해 전립선 표면을 추출한다. 둘째, 표면 형상의 지역적 최적화로 인한 흘을 방지하기 위하여 기하학 정보를 이용한 흘 제거 기법을 수행한다. 셋째, 해부학적으로 변이가 큰 표면 형상은 2차원 기울기 정보를 이용하여 보정한다. 이때, 보정된 표면 형상은 한정된 정점의 개수로 산정되어 매끄럽게 표현되지 않기 때문에 표면재구성 및 평활화 기법을 이용하여 부드러운 형상으로 표현한다. 제안방법의 평가를 위하여 육안평가와 정확성 평가 그리고 수행시간을 측정하였다. 정확성 평가는 두 명의 임상전문의의 수동분할 결과와 자동분할 결과 간의 평균거리차이와 중복볼륨비율을 측정하였다. 실험 결과 평균거리차이는 0.3${\pm}$0.21mm 측정되었고, 중복볼륨 비율은 96.31${\pm}$2.71% 측정되었다. 20명의 환자 데이터에 대한 전체 수행시간은 평균 16초로 측정되었다.

• 한국정밀공학회지
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• 제10권4호
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• pp.81-93
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• 1993

The three dimensional(3D) shape reconstruction from two dimensional(2D) cross-sections can be completed through three main phases : the input compilation, the triangular grid formation, and the smooth surface construction. In the input compilation phase, the cross-sections are analyzed to exctract the input data required for the shape reconstruction. This data includes the number of polygonized contours per cross-section and the vertices defining each polygonized contour. In the triangular grid formation phase, a triangular grid, leading to a polyhedral approximations, is constructed by extracting all the information concerning contour links between two adjacent cross- sections and then performing the appropriate triangulation procedure for each contour link. In the smooth surface construction phase, a smooth composite surface interpolating all vertices on the triangular grid is constructed. Both the smooth surface and the polyhedral approximation can be used as reconstructed models of the object. This paper proposes a new method for reconstructing the geometric model of a 3D objdect from a sequence of planar contours representing 2D cross-sections of the objdect. The method includes the triangular grid formation algorithms for contour closing, one-to-one branching, and one-to-many braanching, and many-to-many branching. The shape reconstruction method has been implemented on a SUN workstation in C.

• 대한산업공학회지
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• 제21권3호
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• pp.329-343
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• 1995

Traditionally, machining process sequence was influenced and constrained by the design information obtained from CAD data base, i.e., class of operations, geometric shape, tooling, geometric tolerance, etc. However, even though all the constraints from design information are considered, there may exist more than one way to feasibly machine parts. This research is focused on the integrated problem of operations sequencing and machine tools selection in the presence of the product mix and their production volumes. With the transitional costs among machining operations, the operation sequencing problem can be formulated as a well-known Traveling Salesman Problem (TSP). The transitional cost between two operations is expressed as the sum of total machining time of the parts on a machine for the first operation and transportation time of the parts from the first machine to a machine for the second operation. Therefore, the operation sequencing problem formulated as TSP cannot be solved without transitional costs for all operation pairs. When solved separately or serially, their mutual optima cannot be guaranteed. Machining operations sequencing and machine tool selection problems are two core problems in process planning for discretely machined parts. In this paper, the interrelated two problems are integrated and analyzed, zero-one integer programming model for the integrated problem is formulated, and the solution methods are developed using a Tabu Search technique.

• 한국정밀공학회지
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• 제16권2호통권95호
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• pp.68-73
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• 1999

Generally, most of machining processes are done according to the dimention of the draft made by CAD. However, there are many cases that a sample is given without the draft because of the simplicity of the shape in the machining of 2D objects. To cut the same shape as the given sample, this paper proposes the method to extract the geometric information about a large sample using the robot vision and to draw the demensional draft for the machining. Because the resolution of one frame in the vision system is too low, it is necessary to set up a camera according to the desired resolution and to capture the image moving along the contour. And the overall outline can be compounded of the sequentially captured images. In the experiment, we compared the product after the cutting with the original sample and found that the size of two objects was coincided within the allowed error bound.

• 한국정밀공학회지
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• 제24권5호
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• pp.62-67
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• 2007

A simple dimension measuring method for the measurement of human bust has been developed using projection moire. The 3-D data of a human bust was calculated from the 2dimensional image information obtained by the stripe using projection moire. The creation of 3-D geometric shape by digitizing real objects has been widely investigated in reverse engineering(RE). This procedure generally consists of three basic steps: data capture, data alignment and model reconstruction. In order to achieve a complete model, multiple scans must be taken and aligned.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -3
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• pp.1523-1526
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• 2002

In this paper, we propose a method fur measuring the dimensions of an arbitrary object using geometric relationship between a perspective projection image and a rectangular parallelepiped model. For recognizing the vertexes of the rectangular parallelepiped surrounding an arbitrary object, the method adopts a strategy that derives the equations for vertex recognition from the geometrical relationships for image formation between 2D image and the rectangular parallelepiped model. extracts from 2D image with vertical view features (or junctions) of minimum quadrangle circumscribing an arbitrary shape object, and then recognizes vertexes from the features with the equations. Finally, the dimensions of the object are calculated from these results of vertex recognition. By the experimental results, it is demonstrated that this method is very effective to recognize the vertexes of the arbitrary objects.

• Journal of Advanced Marine Engineering and Technology
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• 제19권1호
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• pp.54-59
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• 1995

In this paper, we propose unique CAM system for personal computer that can define the geometric shape in an ease manner and to machine the sculptured surfaces of a mold cavity. In this CAM system, if a user inputs simple initial information such as the control points for a shape definition and a radius of tool etc., all of the procedures for machining will be processed automatically by the CAM system as well as NC commands and simulations. In addition to this, the environment of the CAM system is composed of "C" language for an easy extention of aditional modules. Also, the CAM system with the following characteristics was developed. 1. The optimum tool path satisfying given tolerance limits reduces the time for the high precision machining of sculptured surface in a mold cavity. 2. The generated NC commands can be transmitted to NC directly by the CAM system through RS-232C from PC.C from PC.

• Journal of Information Processing Systems
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• 제8권3호
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• pp.399-408
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• 2012

Hand gesture recognition is an important area of research in the field of Human Computer Interaction (HCI). The geometric attributes of the hand play an important role in hand shape reconstruction and gesture recognition. That said, fingertips are one of the important attributes for the detection of hand gestures and can provide valuable information from hand images. Many methods are available in scientific literature for fingertips detection with an open hand but very poor results are available for fingertips detection when the hand is closed. This paper presents a new method for the detection of fingertips in a closed hand using the corner detection method and an advanced edge detection algorithm. It is important to note that the skin color segmentation methodology did not work for fingertips detection in a closed hand. Thus the proposed method applied Gabor filter techniques for the detection of edges and then applied the corner detection algorithm for the detection of fingertips through the edges. To check the accuracy of the method, this method was tested on a vast number of images taken with a webcam. The method resulted in a higher accuracy rate of detections from the images. The method was further implemented on video for testing its validity on real time image capturing. These closed hand fingertips detection would help in controlling an electro-mechanical robotic hand via hand gesture in a natural way.

• 전자공학회논문지S
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• 제34S권7호
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• pp.78-88
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• 1997

A three dimensional-two spatical dimensions plus time-image segmentation is widely used in a very low bit rate image sequence coding because it can solve the region correspondence problem. Mathematical morphology is a very efficient tool for the segmentation because it deals well with geometric features such as size, shape, contrast and connectivity. But if the motion in the image sequence is large in time axis, the conventional 3D morphological segmentation algorithm have difficulty in solving region correspondence problem. To alleviate this problem, we propose the hierarchical image sequence segmentation algorithm that uses the region motion information. Since the motion of a region in previous level affects that in current level uses the previous motion information to increase region correspondence. Simulation result shows improved performance for sequence frames with large motion.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2004년도 Proceedings of ISRS 2004
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• pp.609-612
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• 2004

Geometric shape in a surface material sometimes produces different slopes that have different illuminations. It causes some difficulties to get same classification results or to identify as an object for the different facets in a surface material. A regression method is suggested to adjust the spectral information of different facets in a surface material using image segments. The method to adjust spectral information in a building facets was very successful. The most important advantage of this method is to keep the intensity of spectral information as well as spectral response. This method can also be implemented in an adaptive way.