• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2007년도 춘계학술발표대회
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• pp.111-114
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• 2007

워터쉐드 변환은 영역 분할 속도가 빠르고, 유연하여 이미지 분할 분야에서 많이 사용되고 있다. 그러나 워터쉐드 변환은 지역적 최소점을 이용하기 때문에 잡음에 민감하고 과분할되는 단점을 가지고 있다. 또한, 기존 연구들은 그레이 스케일 이미지에 대해서만 워터쉐드를 적용하였다. 본 논문에서는 지역적 최소점에 민감한 워터쉐드 변환에 칼라 기울기 이미지와 모폴로지 기법을 적용하였다. 워터쉐드 변환 후의 분할된 영역은 영역 인접 그래프로 구성하였고, 인접 영역에 대하여 칼라 색상 유사도와 텍스쳐 유사도를 이용하여 영역 병합을 수행하였다. 실험 결과 본 논문에서 제안한 알고리즘을 이용할 경우 효과적인 이미지 분할이 가능함을 확인할 수 있었다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2004년도 Proceedings of ISRS 2004
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• pp.428-431
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• 2004

A multi-stage hierarchical clustering technique, which is an unsupervised technique, has been proposed in this paper for classifying the hyperspectral data .. The multistage algorithm consists of two stages. The 'local' segmentor of the first stage performs region-growing segmentation by employing the hierarchical clustering procedure with the restriction that pixels in a cluster must be spatially contiguous. The 'global' segmentor of the second stage, which has not spatial constraints for merging, clusters the segments resulting from the previous stage, using a context-free similarity measure. This study applied the multistage hierarchical clustering method to the data generated by band reduction, band selection and data compression. The classification results were compared with them using full bands.

• 한국컴퓨터그래픽스학회논문지
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• 제8권1호
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• pp.21-28
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• 2002

This paper presents a brush stroke direction creation method to distill painterly expressions from picture images. In actual paintings, each brush stroke has the same directionality in one segmented area. but directionality changes in the area of image border edges. This study employed the following methods to implement the directionality of the brush stroke area by: (1) detecting edge in input images, (2) region splitting and merging based on quad-tree division method, and (3) composing a direction map to create brush strokes with the same directionality in the segmented area. The results of the implementation enabled the simulation of the directionality of the stroke area shown in actual paintings.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2004년도 추계 학술대회논문집
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• pp.15-18
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• 2004

A numerical method for simulating two-phase flows including surface force is presented. The method is based on fractional step method of finite volume formulation and the interface is tracked with PLIC VOF method. In the CSF model, as color function, f, representing the location of interface varies steeply in the interface region, we need to use smoothed function f to get accurate unit normal and the curvature. Peskin kernel is used to get smoothed function f. A spherical drop in static equilibrium and three-dimensional merging of gas bubble are tested, resulting in the validation of this method

• 제어로봇시스템학회논문지
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• 제14권5호
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• pp.444-452
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• 2008

This paper presents an overall image processing approach of defect inspection of patterned TFT-LCD panels for the real manufacturing process. A prototype of AOI(Automatic Optical Inspection) system which is composed of air floating stage and multi line scan cameras is developed. Adjacent pattern comparison algorithm is enhanced and used for pattern elimination to extract defects in the patterned image of TFT-LCD panels. New region merging algorithm which is based on border expansion is proposed to identify defects from the pattern eliminated defect image. Experimental results show that a developed AOI system has acceptable performance and the proposed algorithm reduces environmental effects and processing time effectively for applying to the real manufacturing process.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 Ⅳ
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• pp.1964-1967
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• 2003

워터쉐드 알고리즘에 의해 과분할 된 영상은 이후 영상의 이해 및 분석 작업의 편의성을 위하여 영역 병합 작업이 필요하다. 본 논문에서는 유사한 색상을 갖는 영역의 경계선을 보다 잘 유지할 수 있도록 통합 비유사도를 정의하고, 이를 이용한 영역 병합 방법을 제안한다. 통합 비유사도는 영역의 색상 정보, 인접한 두 영역 사이의 평균 그래디언트 값 정보, 두 영역 사이의 인접한 픽셀 수 정보를 이용하여 정의된다. 영역 병합과정에서는 영역 면적의 크기와 영역간 통합 비유사도를 고려한 3 단계 영역 병합 방법을 수행한다. 자연 영상에 대한 실험 결과 제안한 방법이 기존의 방법보다 경계선 정보를 보다 잘 유지하고 사람이 느끼기에 보다 정확한 영역 병합 결과를 나타냄을 확인하였다.

• 대한기계학회논문집
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• 제18권10호
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• pp.2779-2786
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• 1994

This study presents an experimental investigation of the effect of the wake on mass transfer about a circular cylinder in crossflow. The flat-plate wake was generated by merging two mirror images of turbulent boundary layers that were well developed along the both sides of flat plate with a sharp trailing edge. The velocity field was measured by a hot-wire system and the mass transfer rate by a naphthalene sublimation method. The mixing and developing stages of the wake were addressed to identify flow conditions. The mass transfer effects of different developing stages of the wake was discussed in detail. It is noted that a local maximum appears not at the front stagnation point but at a point a little downstream when the cylinder is located in the nearwake region and much more elevated mass transfer rate is obtained compared to effect of free-stream turbulence.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -1
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• pp.482-485
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• 2000

A modified watershed transform is proposed which is context-free marker-controlled and minima imposition-free to reduce the over-segmentation and to speedup the transform. In contrast to the conventional methods in which a priori knowledge, such as flat zones, zones of homogeneous texture, and morphological distance, is required for marker extraction, context-free marker extraction is proposed by using the attention operator based on the GST (generalized symmetry transform). By using the context-free marker, the proposed watershed transform exploit marker-constrained labeling to speedup the computation and to reduce the over-segmentation by eliminating the unnecessary geodesic reconstruction such as the minima imposition and thereby eliminating the necessity of the post-processing of region merging. The simulation results show that the proposed method can extract context-free markers inside the objects from the complex background that includes multiple objects and efficiently reduces over-segmentation and computation time.

• 방송공학회논문지
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• 제8권2호
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• pp.172-180
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• 2003

본 논문은 얼굴 모션 캡쳐 애니메이션을 위한 빠르고 정확한 추출 및 추적 알고리즘을 제안한다. 제안한 알고리즘은 추출 및 추적의 두 단계로 구성된다. 먼저 신경회로망 기반의 영역 병합 기법을 이용하여 입력 영상으로부터 다중 마크를 분리한다. 그 다음, 신경회로망 기반의 추적 알고리즘을 사용하여 각각의 프레임에서 추출된 다중 마크들을 추적한다. 실험의 결과는 추출단계에서는 노이즈를 제거하고 처리 시간을 줄일 수 있었다. 또한 낮은 프레임율에서도 성능이 좋은 추적 결과를 얻을 수 있었다.

• ALGAE
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• 제33권3호
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• pp.215-229
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• 2018

In this study, the phylogenetic relationships among the genera Alsidium C. Agardh and Bryothamnion $K{\ddot{u}}tzing$ were investigated. Phylogenetic analyses using the plastid-encoded markers rbcL, psbA, and the mitochondrial barcode region (COI-5P) resolved a well-supported clade that included the species Alsidium corallinum, Bryothamnion seaforthii, and B. triquetrum. Our results indicated that taxonomic recognition of the genus Bryothamnion is not supported and two species of Bryothamnion are reallocated to Alsidium. A reexamination of the morphological definition of Alsidium is provided with an updated diagnosis of the genus and a morphology-based comparison of species that are currently circumscribed under this generic name. Furthermore, we reviewed morphological differences and similarities between Alsidium and the genus Digenea, both belonging to the tribe Alsidieae, discussing the most relevant morphological characters.