• Title/Summary/Keyword: Voronoi transform

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Performance Analysis of a Rotation-Transform Aided QPSK over Impulsive Noise Using Rieman Integral over Voronoi Cell (보로노이 셀에서 리만 적분을 이용한 임펄스 잡음 환경에서 동작하는 회전 변환 QPSK 기법의 성능 해석)

  • Choi, Byoungjo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.38A no.3
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    • pp.224-239
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    • 2013
  • An exact performance analysis of an ML detector for a 2-dimensional rotation-transform aided QPSK system operating over an impulsive noise environment is presented using Rieman integrals of a two-dimensional Gaussian Q-function over Voronoi cells. A set of interesting features of the Voronoi cells is also characterised systematically. An optimum rotation angle yielding the minimum BER is also studied. The differences between the proposed exact method and the previous approximate analysis method are investigated in terms of the corresponding BERs and the derived optimum angles.

REGION-ORIENTED TRANSFORM CODING OF STILL IMAGES USING VORONOI DIAGRAMS AND SCHMIDT'S ORTHOGONALIZATION

  • Ichiro-Matsuda;Susumu-Itoh
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 1999.06a
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    • pp.69-76
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    • 1999
  • This paper proposes a new region-oriented coding scheme of still images. The scheme first segments an image into homogeneous regions by making use of Voronoi diagrams. Then luminance components in each Voronoi region are encoded using a transform coding technique which employs the Schmidt's orthogonalization method to produce orthonormal basis-functions for arbitrarily shaped regions. In this technique, coding efficiency depends on the properties of initial vectors to be orthogonalized. Therefore we adaptively select a set of initial vectors as well as the order in which these vectors are orthogonalized. Simulation results indicate that the proposed coding scheme achieves higher coding performance with much less computation than the KLT-based scheme which we reported formerly.

Improved Euclidean transform method using Voronoi diagram (보로노이 다이어그램에 기반한 개선된 유클리디언 거리 변환 방법)

  • Jang Seok Hwan;Park Yong Sup;Kim Whoi Yul
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.29 no.12C
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    • pp.1686-1691
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    • 2004
  • In this paper, we present an improved method to calculate Euclidean distance transform based on Guan's method. Compared to the conventional method, Euclidean distance can be computed faster using Guan's method when the number of feature pixels is small; however, overall computational cost increases proportional to the number of feature pixels in an image. To overcome this problem, we divide feature pixels into two groups: boundary feature pixels (BFPs) and non-boundary feature pixels (NFPs). Here BFPs are defined as those in the 4-neighborhood of foreground pixels. Then, only BFPs are used to calculate the Voronoi diagram resulting in a Euclidean distance map. Experimental results indicate that the proposed method takes 40 Percent less computing time on average than Guan's method. To prove the performance of the proposed method, the computing time of Euclidean distance map by proposed method is compared with the computing time of Guan's method in 16 images that are binary and the size of 512${\times}$512.

Systolic Arrays for Constructing Static and Dynamic Voronoi Diagrams (두 형의 Voronoi Diagram 구축을 위한 Systolic Arrays)

  • O, Seong-Jun
    • ETRI Journal
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    • v.10 no.3
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    • pp.125-140
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    • 1988
  • Computational geometry has wide applications in pattern recognition, image processing, VLSI design, and computer graphics. Voronoi diagrams in computational geometry possess many important properites which are related to other geometric structures of a set of point. In this pater the design of systolic algorithms for the static and the dynamic Voronoi diagrams is considered. The major motivation for developing the systolic architecture is for VLSI implementation. A new systematic transform technique for designing systolic arrays, in particular, for the problem in computational geometry has been proposed. Following this procedure, a type T systolic array architecture and associated systolic algorithms have been designed for constructing Voronoi diagrams. The functions of the cells in the array are also specified. The resulting systolic array achieves the maximal throughput with O(n) computational complexity.

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Study on the Service Area Determination of the Public Facilities Applying Voronoi Diagrams - Case Study of the Fire Services in Gangnam-Gu, Seoul - (보로노이 다이어그램을 적용한 공공서비스의 관할구역 설정에 대한 연구 - 서울 강남 지역의 소방서를 사례로 하여 -)

  • Kim, Jae-Won;Kang, Jee-Hoon;Lee, Eui-Young;Kang, Yong-Jin
    • Spatial Information Research
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    • v.15 no.3
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    • pp.203-218
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    • 2007
  • The purpose of this article is to set up the scientific and reasonable norm of location and service area determination instead of the pro-administrative lacking availability, so as to propose more practical and reasonable standard of space unit for the location of facilities. This article has accepted the method of Voronoi Diagram as a new scientific and reasonable criteria. The article chooses and realizes a model that can propose a new service area, transform and apply to improve its reality, and assesses which has more reality and compatibility by comparing the models. The result from this procedure can be adapted in objectification of the service area determination and formation of the standard space unit.

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Patient-Specific Mapping between Myocardium and Coronary Arteries using Myocardial Thickness Variation

  • Dongjin Han
    • International journal of advanced smart convergence
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    • v.13 no.2
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    • pp.187-194
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    • 2024
  • For precise cardiac diagnostics and treatment, we introduce a novel method for patient-specific mapping between myocardial and coronary anatomy, leveraging local variations in myocardial thickness. This complex system integrates and automates multiple sophisticated components, including left ventricle segmentation, myocardium segmentation, long-axis estimation, coronary artery tracking, and advanced geodesic Voronoi distance mapping. It meticulously accounts for variations in myocardial thickness and precisely delineates the boundaries between coronary territories according to the conventional 17-segment myocardial model. Each phase of the system provides a step-by-step approach to automate coronary artery mapping onto the myocardium. This innovative method promises to transform cardiac imaging by offering highly precise, automated, and patient-specific analyses, potentially enhancing the accuracy of diagnoses and the effectiveness of therapeutic interventions for various cardiac conditions.

Uncertainty for Privacy and 2-Dimensional Range Query Distortion

  • Sioutas, Spyros;Magkos, Emmanouil;Karydis, Ioannis;Verykios, Vassilios S.
    • Journal of Computing Science and Engineering
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    • v.5 no.3
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    • pp.210-222
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    • 2011
  • In this work, we study the problem of privacy-preservation data publishing in moving objects databases. In particular, the trajectory of a mobile user in a plane is no longer a polyline in a two-dimensional space, instead it is a two-dimensional surface of fixed width $2A_{min}$, where $A_{min}$ defines the semi-diameter of the minimum spatial circular extent that must replace the real location of the mobile user on the XY-plane, in the anonymized (kNN) request. The desired anonymity is not achieved and the entire system becomes vulnerable to attackers, since a malicious attacker can observe that during the time, many of the neighbors' ids change, except for a small number of users. Thus, we reinforce the privacy model by clustering the mobile users according to their motion patterns in (u, ${\theta}$) plane, where u and ${\theta}$ define the velocity measure and the motion direction (angle) respectively. In this case, the anonymized (kNN) request looks up neighbors, who belong to the same cluster with the mobile requester in (u, ${\theta}$) space: Thus, we know that the trajectory of the k-anonymous mobile user is within this surface, but we do not know exactly where. We transform the surface's boundary poly-lines to dual points and we focus on the information distortion introduced by this space translation. We develop a set of efficient spatiotemporal access methods and we experimentally measure the impact of information distortion by comparing the performance results of the same spatiotemporal range queries executed on the original database and on the anonymized one.