• 한국정보과학회논문지:데이타베이스
• /
• 제36권4호
• /
• pp.263-279
• /
• 2009

CBIR(Content-based Image Retrieval) 시스템의 질의 처리에 사용되는 모양 특징은 크게 경계 기반과 영역 기반 등 두 가지로 나눌 수 있다. 경계기반 특징은 간단하지만 영역 기반 특징에 비해 효과적이지 않다. 영역 기반 모양 특징을 사용하는 대부분의 시스템은 먼저 영역을 추출해야 한다. 하지만 기존의 영역 기반 시스템들은 구현이 복잡하고, 특히 정확한 영역 추출이 어려우며 영역 간의 위치적인 관계가 거리 모델(distance model)에 반영되어 있지 않다. 본 논문에서는 Canny 에지 검출과 Hough 변환에 기반하여 목표 내부의 에지를 검출하고, 이와 함께 영역확장을 이용하여 목표 물체 내부의 영역을 정확히 추출할 수 있는 방법을 제안하였다. 또한 영역 간의 인접 관계를 이용한 수정된 IRM(Integrated Region Matching) 기법을 제안하였다. 이는 모양 특징을 이용한 유사성 검색에서 영상 간의 거리 모델로서 사용된다. 그리고 실험을 통해 수정된 IRM 기법과 우리의 영역 추출 기법이 효과적임을 보였다. 실험 결과는 새로운 영역 추출 방법이 기존의 다른 방법보다 훨씬 우수함을 보여준다.

• 디지털콘텐츠학회 논문지
• /
• 제5권4호
• /
• pp.257-263
• /
• 2004

본 논문은 객체 기반 스테레오 정합에 있어서, 분할영역 내부에 존재하는 단계적인 변위의 변화를 추정할 수 있는 스테레오 정합 알고리즘에 관한 것이다. 우산 분할영역을 효과적으로 표현할 수 있는 복수의 샘플점들을 선정한 다음에 각 샘플점 주위에 인접한 영역 내부의 미소영역을 취하여 스테레오 정합을 수행한다. 이후, 선택된 각 샘플점의 변위에 의한 평면의 방정식을 이용하여 내부 변위들을 보간한다. 제안된 방법에 따르면, 샘플점에서 얻어진 변위 값을 영역내부로 전파시킴으로써 깊이 추정이 단지 특징점들에서만 국한되는 특징 기반 기법의 문제점을 해결할 수 있으며, 또한 분할영역의 외곽선에서 샘플점을 추출함으로써 단순 영역에서의 깊이 추정이 모호하게 되는 영역기반 기법의 문제점을 효과적으로 억제시킬 수 있다.

• 한국통신학회논문지
• /
• 제22권8호
• /
• pp.1691-1697
• /
• 1997

This paper presents a new motion compensated error coding method suitable for region based image coding system. Compared with block based conding, the region based coding improves subjective quality as it estimates and compensates 2D (or 3D) translantional, rotational, and scaling motion for each regions. although the region based coding has this advantage, its merit is reduced as bock-DCT (2D-DCT) is used to encode motion-compensated error. To overcome this problem, a new region adaptive motion compensated error coding technique which improver subjective and objective quality in the region boundary is proposed in this paper. In the proposed method, regions with large error are estimated using contour of the regions and contrast between the regions. The regions estiated as those with large error are coded by arbitrarily shaped image segment coding method. The mask information of the coded regions is not transmitted because it is estimated as the same algorithm in the encoder and the decoder. The proposed region adaptive motion conpensated error coding method improves about 0.5dB when it is compared with conventional block based method.

• 한국통신학회논문지
• /
• 제24권9B호
• /
• pp.1755-1766
• /
• 1999

A region-based video codec based on the H.263+ standard is examined and its associated novel rate control scheme is proposed in this work. The region-based coding scheme is a hybrid method that consists of the traditional block DCT coding and the object-based coding. Basically, we adopt H.263+ as the platform, and develop a fast macroblock-based segmentation method to implement the region-based video codec. The proposed rate control solution includes rate control in three levels: encoding frame selection, frame-layer rate control and macroblock-layer rate control. The goal is to enhance the visual quality of decoded frames at low bit rates. The efficiency of proposed rate control scheme applied to the region-based video codes is demonstrated via several typical test sequences.

• 한국CDE학회논문집
• /
• 제8권1호
• /
• pp.41-47
• /
• 2003

In this paper, a tetrahedral mesh generation algorithm which uses a grid based method for interior region and an advancing front method for outer surface region is proposed. In order to apply an advancing front method for outer region of an object, a new operator so called a hole operator has been developed to handle multiple shells. With this grid based approach in the interior region, more stable and uniform meshes can be constructed especially in the interior region.

• Journal of Computing Science and Engineering
• /
• 제9권1호
• /
• pp.9-19
• /
• 2015

The most important challenge in the region-based abstraction method as an approach to compute the state space of time Petri Nets (TPNs) for model checking is that the method results in a huge number of regions, causing a state explosion problem. Thus, region-based abstraction methods are not appropriate for use in developing practical tools. To address this limitation, this paper applies a modification to the basic region abstraction method to be used specially for computing the state space of TPN models, so that the number of regions becomes smaller than that of the situations in which the current methods are applied. The proposed approach is based on the special features of TPN that helps us to construct suitable and small region graphs that preserve the time properties of TPN. To achieve this, we use TPN-TCTL as a timed extension of CTL for specifying a subset of properties in TPN models. Then, for model checking TPN-TCTL properties on TPN models, CTL model checking is used on TPN models by translating TPN-TCTL to the equivalent CTL. Finally, we compare our proposed method with the current region-based abstraction methods proposed for TPN models in terms of the size of the resulting region graph.

• 전자공학회논문지S
• /
• 제34S권11호
• /
• pp.102-113
• /
• 1997

In this paepr, a new image segmentation method reducing efficiently contour information causing bottleneck problem at segmentatio-based very low bit rate codingis proposed, while preserving objective and subjective quality. It consists of 4-level hierarchical image segmentation based on mathematical morphology and 1-leve region merging structure using contast of two adjacent regions. For two adjacent region pairs at the fourth level included in each region of the thid level, contrast is calculated. Among the pairs of two adjacent regions with less value than threshold, two adjacent regions having the minimum contrast are merged first. After region merging, texture of the merged region is updated. The procedure is performed recursively for all the adjacent region pairs at the fourth level included in each region of the third level. Compared with the previous method, the objective and subjective image qualities are similar. But it reduces 46.65% texture information on the average by decreasing total region number to be tansmitted. Specially, it shows reduction of the 23.95% contour information of the average. Thus, it can improve efficiently the bottleneck problem at segementation-based very low bit rate coding.

• Journal of the Korean Society for Industrial and Applied Mathematics
• /
• 제18권2호
• /
• pp.129-142
• /
• 2014

We propose a variational segmentation model based on statistical information of intensities in an image. The model consists of both a local region-based energy and a global region-based energy in order to handle misclassification which happens in a typical statistical variational model with an assumption that an image is a mixture of two Gaussian distributions. We find local ambiguous regions where misclassification might happen due to a small difference between two Gaussian distributions. Based on statistical information restricted to the local ambiguous regions, we design a local region-based energy in order to reduce the misclassification. We suggest an algorithm to avoid the difficulty of the Euler-Lagrange equations of the proposed variational model.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2000년도 ITC-CSCC -2
• /
• pp.843-846
• /
• 2000

An optical flow-based motion estimation algorithm is proposed for video coding. The algorithm uses block-matching motion estimation with an adaptive search region. The search region is computed from motion fields that are estimated based on the optical flow. The algorithm is based on the fact that true block-motion vectors have similar characteristics to optical flow vectors. Thereafter, the search region is computed using these optical flow vectors that include spatial relationships. In conventional block matching, the search region is fixed. In contrast, in the new method, the appropriate size and location of the search region are both decided by the proposed algorithm. The results obtained using test images show that the proposed algorithm can produce a significant improvement compared with previous block-matching algorithms.

• Journal of Forest and Environmental Science
• /
• 제32권4호
• /
• pp.384-391
• /
• 2016

In this study, regions infected by pine wilt disease were extracted by using object-based classification method (OB-infected region), and the characteristics of special distribution about OB-infected region were figured out. Scale 24, Shape 0.1, Color 0.9, Compactness 0.5, and Smoothness 0.5 was selected as the objected-based, optimal weighted value of OB-infected region classification. The total accuracy of classification was high with 99% and Kappa coefficient was also high with 0.97. The area of OB-infected region was approximately 90 ha, 16% of the total area. The OB-infected region in Age class V and VI was intensively distributed with 97% of the total. Also, The OB-infected region in Middle and Large DBH class was intensively distributed with 99% of the total. In terms of the topographic characteristics of OB-infected region, the damages occurred approximately 86% below the altitude of 200 m, and occurred 91% with a slope less than 10 degree. The damage occurred a lot in low hilly mountain and undulating slope. In addition, the accessibility to road and residential area from OB-infected region was less than 300 m in large part. Overall, it was figured out that artificial effect is stronger than natural effect with regard to the spread of pine wilt disease.