• Journal of Advanced Marine Engineering and Technology
• /
• 제20권1호
• /
• pp.44-48
• /
• 1996

In manufacturing of exact products, the offsetting is required to transfer the design data of shape to manufacturing data. In offsetting the degeneracies are occurred, and these problems are mere difficult in freeform shapr manufacuring. This paper is using the geometric properties of B-spline curves to solve the degeneracy of offsetting and to generating of enhanced offsetting. The offsetting of B-spline control polygon spans generates exact control polygon of original shapes. This method is faster in generating offset curve than the normal offsetting, and the resulted offset curves are exact. The additional property of this method is using to control offset shape as B-spline curves. We believe that this method is as effective solution for modifying of offset curves.

• 한국지능시스템학회논문지
• /
• 제19권5호
• /
• pp.683-688
• /
• 2009

본 논문에서는 비젼을 이용한 영상처리 기술을 기반으로 비접촉식 미세 측정 광학기에 의해 측정된 이미지를 템플릿 매칭과 B-Spline 보간법에 의해 보다 빠르고, 정밀한 복원 기법을 제안한다. 이를 위해 먼저 각각의 이미지로부터 매칭 템플릿과 피 매칭 템플릿을 검출한다. 그런 다음 기준면으로부터 두 이미지의 중첩되는 부분의 롤, 피치, 요 오차를 보정하여 정합시킨다. 그리고 B-Spline 보간법에 의해 정합된 부분을 연속화한다. 마지막으로, 제안된 방법은 실험을 통해 그 응용 가능성을 증명한다.

• 한국수학교육학회지시리즈B:순수및응용수학
• /
• 제10권4호
• /
• pp.255-263
• /
• 2003

We compare the computing times on the bicubic B-spline dueing to the algorithms.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
• /
• pp.679-682
• /
• 1988

From the viewpoint of general recognition system, B-spline is introduced for the approximation and recognition of human profile contours. Profile contour is approximated to the cublic B-spline curve by least square fitting so that B-Spline nodes nearly correspond with the curvature extrema of the contour. This method is designed for the spline to be good features in recognition, and also showed good approximation compared with the variants of B-spline appraximation.

• 대한조선학회지
• /
• 제22권3호
• /
• pp.19-26
• /
• 1985

This paper deals with the representation and fairing of ship hull using a B-spline surface which is known as a 3-D model in computer aided free-form design. The first part of this paper is devoted to the fundamental concepts of B-spline theory and its geometrical characteristics. In its second part are described the facillities for efficient application, fast rendering of B-spline surface, and intersection of B-spline surfaces. The examples are presented with actual application to a real ship in the last part. And also a new concept of evaluating the surface fairness by the Gaussian curvature isolines is briefly discussed and its examples are presented.

• Journal of the Korean Society for Industrial and Applied Mathematics
• /
• 제20권2호
• /
• pp.151-161
• /
• 2016

In this paper, we present a $C^3$ quartic B-spline approximation of circular arcs. The Hausdorff distance between the $C^3$ quartic B-spline curve and the circular arc is obtained in closed form. Using this error analysis, we show that the approximation order of our approximation method is six. For a given circular arc and error tolerance we find the $C^3$ quartic B-spline curve having the minimum number of control points within the tolerance. The algorithm yielding the $C^3$ quartic B-spline approximation of a circular arc is also presented.

• Journal of the Korean Society for Industrial and Applied Mathematics
• /
• 제3권1호
• /
• pp.81-98
• /
• 1999

In spite of the well developed theory and the practical use of the univariate B-spline, the theory of multivariate B-spline is very new and waits its practical use. We compare in this article the multivariate B-spline approximation with the polynomial approximation for the surface fitting. The graphical and numerical comparisons show that the multivariate B-spline approximation gives much better fitting than the polynomial one, especially for the surfaces which vary very rapidly.

• 한국전산유체공학회지
• /
• 제3권2호
• /
• pp.1-8
• /
• 1998

We make use of cubic B-spline interpolation function in two cases: heat conduction and fluid flow problems. Cubic B-spline test function is employed because it is superior to approximation of linear and non-linear problems. We investigated the accuracy of the numerical formulation and focused on the position of the breakpoints within the computational domain. When the domain is divided by partitions of equal space, the results show poor accuracy. For the case of a heat conduction problem this partition can not reflect the temperature gradient which is rapidly changed near the wall. To correct the problem, we have more grid points near the wall or the region which has a rapid change of variables. When we applied the unequally spaced breakpoints, the results show high accuracy. Based on the comparison of the linear problem, we extended to the highly non-linear fluid flow problems.

• 대한조선학회논문집
• /
• 제29권3호
• /
• pp.1-14
• /
• 1992

본 논문에서는 형상의 기하학적 특성을 나타내는 형상계수들로부터 B-spline 곡면식으로 표현 되는 3차원 자유곡면의 생성을 시도하고 있다. 이것은 형상계수들의 결정과 이들 형상계수들의 Coons 곡면 및 B-spline 곡면과의 결합으로 이루어진다. 본 방법의 유용성 확인을 위해서 구상선수 형상에 유사한 곡면의 생성을 시도해 보았다.

• 한국정밀공학회지
• /
• 제20권10호
• /
• pp.156-163
• /
• 2003

This research presents modeling of a functional surface which is a constructed free-formed surface. The modeling introduced in this paper adopts modified B-spline that is utilizing approximating technique. The modified B-Spline is constructed with altered control vertices. It is applied to measure points on a surface of an impeller blade. This research builds a surface-modeler accepting inputs of measured points. Generation of cutter-paths for NC machining employs the model of the constructed surfaces. The machined surfaces which is generated in several cases are compared in the aspect of machining accuracy.