• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.10a
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• pp.583-586
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• 2001

본 연구는 영상에서 이진영상을 얻기위하여 최적의 임계값 결정을 영상에 나타난 물체의 형상정보를 근거로한 비트평면 패턴을 이용한 최적 임계화 방법을 제안한다. 제안된 방법은 원영상의 윤곽정보를 가장 많이 포함하는 최상위 비트평면을 사용하여 영상을 중복되지 않는 두 영역으로 구분한 뒤, 두영역의 화소 밝기값의 평균값을 각 각 구하고 두 평균값 사이에서 임계값을 설정하는 전역 임계화 알고리즘이다. 제안된 방법의 타당성을 검토하기 위하여 표준영상을 가지고 N 개의 비트평면으로 분할 한 후, 비트평면에서 전체영상을 중복되지 않는 물체의 영역과 배경영역으로 나누어 영상의 밝기를 비교한후, 두 영역의 영상 밝기의 중간 값을 추하여 임계값으로 결정한 결과 전체영상의 밝기값 분포만을 분석한 결과 보다 원영상의 윤곽을 더 충실히 얻을 수 있었다.

• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.2
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• pp.279-284
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• 2010

The plane curve approach which was proposed by Boukharouba et. al. is a multi-threshold selection method through searching peak-valley based on histogram cumulative distribution function. However the method is required to select parameters to compose plane curve, and the shape of plane curve is affected according to parameters. Therefore detection of peak-valley is effected by parameters. In this paper, we propose an entropy maximizing-based method to select optimal plane curve parameters, and propose a multi-thresholding method based on the selected parameters. The effectiveness of the proposed method is demonstrated by multi-thresholding experiments on various images and comparison with other conventional thresholding methods based on histogram.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.6
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• pp.1169-1174
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• 2001

A new approach for determining global threshold value of binary image is proposed in this paper. In the proposed algorithm, bit-plane information which involve the shapes of original image is used for dividing image into two parts; object and background. Optimal threshold value are selected based on difference values of average between two regions, which is considered in global binary thresholding. Proposed method is no need to set a initial value, and consequently, it is relatively simple as well as robust. Experimental results showed a good performance in preserving edge not only continuous tone images but also document image.

• Journal of Korea Society of Industrial Information Systems
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• v.22 no.3
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• pp.39-47
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• 2017

The Depth Picture can be Encoded by the Plane Coding Mode that is the Method for Coding Mode by Considering a Part of the Picture as the Plane. In this Paper, we Propose the Method of Determining the Variable-sized Block for Variable Block Coding in the Plane Coding Mode for the Depth Picture. The Depth Picture Can be Encoded in the Plane Coding Through Estimating the Plane Which is Close to Pixels in the Block Using Depth Information. The Variable-sized Block Coding in the Plane Coding can be Applied as Follows. It Calculates the Prediction Error between Predicted Depths by the Plane Estimation and the Measured Depths. If Prediction Error is Below the Threshold, the Block is Encoded by Current Size. Otherwise, it Divides the Block and Repeats Above. If the Block is Divided Below the Minimum Size, the Block is not Encoded by the Plane Coding Mode. The Result of the Simulation of the Proposed Method Shows that the Number of Encoded Block is Reduced to 19% as Compared with the Method Using the Fixed-sized Block in the Depth Picture Composed of one Plane.

• Journal of the Korea Society of Computer and Information
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• v.6 no.4
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• pp.1-5
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• 2001

A new approach for determining global threshold value for image binarization is proposed in this paper. In the proposed algorithm, bit-plane information which involve the shapes of original image is used for dividing image into two parts object and background, and then compared each average values. Optimal threshold value are selected in center of two averages. Proposed method is relatively simple but robust and achieved good results in continuous tone images and document image.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.4
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• pp.491-496
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• 2013

Finite element simulations of tensile tests were performed to determine the equivalent stress - equivalent plastic strain curves, critical equivalent stresses, and critical equivalent plastic strains. Then, the curves were used as inputs to finite element simulations of fracture toughness tests to determine the plane strain fracture toughness. The critical COD was taken as the COD when the equivalent plastic strain at the crack tip reached a critical value, and it was used as a crack growth criterion. The relationship between the critical COD and the critical equivalent plastic strain or the reduction of area was found. The relationship between the plane strain fracture toughness and the product of the critical equivalent stress and the critical equivalent plastic strain was also found.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.05a
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• pp.385-390
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• 2009

The gas turbine engine structures usually are placed on high thermal mechanical stress condition. For general low cycle fatigue evaluation, simple fatigue criterion based on critical plane approach is developed. LCF life of turbine wheel is evaluated with this criterion and process contrived together.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.7
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• pp.2858-2864
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• 2012

The differential quadrature method (DQM) is applied to computation of the eigenvalues of in-plane buckling of the curved beams. Critical moments and loads are calculated for the beam subjected to equal and opposite bending moments and uniformly distributed radial loads with various end conditions and opening angles. Results are compared with existing exact solutions where available. The DQM gives good accuracy even when only a limited number of grid points is used. More results are given for two sets of boundary conditions not considered by previous investigators for in-plane buckling: clamped-clamped and simply supported-clamped ends.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.2
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• pp.187-195
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• 1992

This paper propose on the determination of threshold values for extracting shape information of the objects. First, surface curvatures such as mean curvature and gaussian curvature is calculated from given range data. And then local surface regions are classified into the one of 8 primitives by using the sign of mean curvature H and gaussian curvature K. Also from the statistical viewpoint. the range of the zero of H and K in the range is obtained through the analysis of the relation between mean curvature and gaussian curvature. Finally, the effectiveness of the proposed mithod in this paper is demonstrated by comparing with a case, where the zero threshold is arbitrarily obtained.

• Journal of Ocean Engineering and Technology
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• v.26 no.2
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• pp.26-32
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• 2012

In this paper, the effects of irregular bead shapes on fatigue life were investigated. A modified S-N curve method was used to estimate the fatigue life, which considered the inherent multiaxiality caused by the geometrical feature produced by the welding process. The point method of the critical distance method was used to determine the fatigue effective stress. Three types of fillet joint models were tested in the fatigue experiments. For each model, real bead shapes were collected using a 3D laser scanner, and finite element analyses were performed. The results of the analyses with actual bead shapes were compared with those using an idealized bead shape model. The results of the present analytical methods showed good agreement with the experimental results.