• 대한기계학회논문집A
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• 제27권5호
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• pp.697-704
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• 2003

In this paper, the visual tracking system for arbitrary shaped moving object is proposed. The established tracking system can be divided into model based method that needs previous model for target object and image based method that uses image feature. In the model based method, the reliable tracking is possible, but simplification of the shape is necessary and the application is restricted to definite target mod el. On the other hand, in the image based method, the process speed can be increased, but the shape information is lost and the tracking system is sensitive to image noise. The proposed tracking system is composed of the extraction process that recognizes the existence of moving object and tracking process that extracts dynamic characteristics and shape information of the target objects. Specially, active contour model is used to effectively track the object that is undergoing shape change. In initializatio n process of the contour model, the semi-automatic operation can be avoided and the convergence speed of the contour can be increased by the proposed effective initialization method. Also, for the efficient solution of the correspondence problem in multiple objects tracking, the variation function that uses the variation of position structure in image frame and snake energy level is proposed. In order to verify the validity and effectiveness of the proposed tracking system, real time tracking experiment for multiple moving objects is implemented.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제18권2호
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• pp.181-192
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• 2014

In this paper, we propose a robust real-time myocardial border tracking algorithm for echocardiography. Commonly, after an initial contour of LV border is traced at one or two frame from the entire cardiac cycle, LV contour tracking is performed over the remaining frames. Among a variety of tracking techniques, optical flow method is the most widely used for motion estimation of moving objects. However, when echocardiography data is heavily corrupted in some local regions, the errors bring the tracking point out of the endocardial border, resulting in distorted LV contours. This shape distortion often occurs in practice since the data acquisition is affected by ultrasound artifacts, dropout or shadowing phenomena of cardiac walls. The proposed method deals with this shape distortion problem and reflects the motion realistic LV shape by applying global deformation modeled as affine transform partitively to the contour. We partition the tracking points on the contour into a few groups and determine each affine transform governing the motion of the partitioned contour points. To compute the coefficients of each affine transform, we use the least squares method with equality constraints that are given by the relationship between the coefficients and a few contour points showing good tracking results. Many real experiments show that the proposed method supports better performance than existing methods.

• 지능정보연구
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• 제8권2호
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• pp.105-115
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• 2002

본 논문에서는 4 방향 윤곽선 추적 알고리즘(contour tracking algorithm)과 개선된 ART1을 이용한 영문 명함인식 방법을 제안한다. 영문 명함 영상에서 문자열 추출은 영상을 3배로 축소하여 수평 스미어링 기법(smearing method)과 4방향 윤곽선 추적 방법을 적용하여 문자열 후보 영역을 추출하고 수평 및 수직의 비율과 면적을 이용하여 문자열 영역과 비문자열 영역을 구분하였다. 추출된 문자열 영역에서 개별 문자 추출은 수평 스미링 기법과 윤곽선 추적 알고리즘을 이용하여 추출하였고 개별 문자들의 인식은 ART1 알고리즘을 개선하여 인식에 적용하였다. 본 논문에서 제안한 ARTI 알고리즘은 퍼지 합 접속 연산자를 이용하여 유사도를 동적으로 조정함으로써 기존의 ART1을 개선하였다. 추출 및 인식 실험 결과, 제안된 추출 및 인식 방법이 영문 명함 인식에서 효율적인 것을 확인하였다.

• Journal of information and communication convergence engineering
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• 제9권6호
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• pp.666-670
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• 2011

In this paper, we propose a stable active contour based tracking method which utilizes the bimodal segmentation technique to obtain a background color diminished image frame. The proposed method overcomes the drawback of the Mansouri model which is liable to fall into a local minimum state when colors appear in the background that are similar to the target colors. The Mansouri model has been a foundation for active contour based tracking methods, since it is derived from a probability based interpretation. By stabilizing the model with the proposed speed function, the proposed model opens the way to extend probability based active contour tracking for practical applications.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(4)
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• pp.89-92
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• 2001

In this paper, we propose a new approach for tracking a moving object in moving image sequences using active contour models and optical flow. In our approach object segmentation is achieved by active contours, and object tracking is done by motion estimation based on optical flow. To get more dynamic characteristics, Lagrangian dynamics combined to the active contour models. For the optical flow computation, a method, which is based on Spatiotempo-ral Energy Models, is employed to perform robust tracking under poor environments. A prototype real tracking system has been developed and applied to a contents-based video retrieval systems.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2009년 추계학술대회논문집
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• pp.193-200
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• 2009

Recently, there have been efforts to construct hybrids among the existing methodologies for multiphase flow such as VOF, Level Set, and Front Tracking with the intention of facilitating simulations of general three-dimensional problems. As one of the hybrid method, we have developed the Level Contour Reconstruction Method (LCRM) for general three-dimensional multiphase flows including phase change. The main idea was focused on simplicity and a robust algorithm especially for the three-dimensional case. It combines characteristics of both Front Tracking and Level Set methods. While retaining an explicitly tracked interface using interfacial elements, the calculation of a vector distance function plays a crucial role in the periodic reconstruction of the interface elements in the LCRM method to maintain excellent mass conservation and interface fidelity. In addition, compact curvature formulation is incorporated for the calculation of the surface tension force thereby reducing parasitic currents to a negligible level.

• Journal of Information Processing Systems
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• 제7권3호
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• pp.519-530
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• 2011

A Snake is an active contour for representing object contours. Traditional snake algorithms are often used to represent the contour of a single object. However, if there is more than one object in the image, the snake model must be adaptive to determine the corresponding contour of each object. Also, the previous initialized snake contours risk getting the wrong results when tracking multiple objects in successive frames due to the weak topology changes. To overcome this problem, in this paper, we present a new snake method for efficiently tracking contours of multiple objects. Our proposed algorithm can provide a straightforward approach for snake contour rapid splitting and connection, which usually cannot be gracefully handled by traditional snakes. Experimental results of various test sequence images with multiple objects have shown good performance, which proves that the proposed method is both effective and accurate.

• 한국컴퓨터정보학회논문지
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• 제3권1호
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• pp.81-94
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• 1998

영상에서 관심있는 물체의 윤곽선을 추출하기 위해서 Kass등은 Snakes라고 불리우는 능동적 윤곽선 모델(active contour model)을 제안하였다. Snakes 모델은 내부 에너지,영상 에너지, 외부 에너지라는 에너지 함수를 사용하여 물체의 윤곽선을 정의하는 모델로 이 에너지 함수를 최소화함으로써 물체의 윤곽선을 찾을 수 있다 이 모델은 속도가 느리며초기화에 민감하다. 이 문제를 개선하기 위해 Gunn은 두 개의 초기화를 이용하여 정확한 윤곽선을 추출하고 초기화에 덜 민감하도록 하였다. 이 방법은 기존의 다른 방법에 비해 정확한 윤곽선을 추출할 수 있었으나, 속도면 에서는 상당히 효율적이지 못하고 잡음에 민감하였다. 본 논문에서는 이 문제를 해결하기 위하여 snakes을 이루는 각 윤곽점에 8$\times$8크기의 윈도우를 적용하여 윈도우내의 화소에 대해서만 에너지 최소화 알고리즘을 적용하였다.본 논문에서 제안한 방법은 원 영상과 컵 영상의 윤곽선 추출에 적용하였다. 제안한 방법을사용하여 얼굴을 추적하므로써 가상현실등에 응용되고 물체의 움직임 추적에도 응용될 수 있다.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 추계학술대회
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• pp.150-153
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• 1997

The proposed tracking algorithm approaches geometrical method or position, direction, width of vessel. This algorithm using continuity of vessel in spatial coordinates used to determine direction of the center point, after estimating boundary point in dynamic region. Therefore the tracking of vessel's contour is tracked contour as direction of entire contour in coronary artery. This algorithm is automatically processed by DIP as a compared with conventional method, because searching area varies adaptively to allocate searching region from extracted information at past. And ML estimation expressed robust method or angiography as evaluating sample values after preprocessing.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 신호처리소사이어티 추계학술대회 논문집
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• pp.153-156
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• 2003

This paper proposes a video tracking method for a deformable moving object using an active contour model. In order to decide the convergent directions of the contour points automatically, a new energy function based on a frame difference map and an updating rules of the frame difference map are presented. Experimental results on a set of synthetic and real image sequences showed that the proposed method can fully track a speedy deformable object while extracting the boundary of the object exactly in every frame.