• 디지털산업정보학회논문지
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• 제9권1호
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• pp.141-150
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• 2013

This study proposes technology using Active Shape Model to track the object separating it by depth-sensors. Unlike the common visual camera, the depth-sensor is not affected by the intensity of illumination, and therefore a more robust object can be extracted. The proposed algorithm removes the horizontal component from the information of the initial depth map and separates the object using the vertical component. In addition, it is also a more efficient morphology, and labeling to perform image correction and object extraction. By applying Active Shape Model to the information of an extracted object, it can track the object more robustly. Active Shape Model has a robust feature-to-object occlusion phenomenon. In comparison to visual camera-based object tracking algorithms, the proposed technology, using the existing depth of the sensor, is more efficient and robust at object tracking. Experimental results, show that the proposed ASM-based algorithm using depth sensor can robustly track objects in real-time.

• Journal of International Society for Simulation Surgery
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• 제2권1호
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• pp.17-25
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• 2015

Purpose In this paper, we propose a robust 3D vessel tracking algorithm by utilizing an active contour model and unscented Kalman filter which are the two representative algorithms on segmentation and tracking. Materials and Methods The proposed algorithm firstly accepts user input to produce an initial estimate of vessel boundary segmentation. On each Computed Tomography Angiography (CTA) slice, the active contour is applied to segment the vessel boundary. After that, the estimation process of the unscented Kalman filter is applied to track the vessel boundary of the current slice to estimate the inter-slice vessel position translation and shape deformation. Finally both active contour and unscented Kalman filter are inter-operated for vessel segmentation of the next slice. Results The arbitrarily shaped blood vessel boundary on each slice is segmented by using the active contour model, and the Kalman filter is employed to track the translation and shape deformation between CTA slices. The proposed algorithm is applied to the 3D visualization of chest CTA images using graphics hardware. Conclusion Through this algorithm, more opportunities, giving quick and brief diagnosis, could be provided for the radiologist before detailed diagnosis using 2D CTA slices, Also, for the surgeon, the algorithm could be used for surgical planning, simulation, navigation and rehearsal, and is expected to be applied to highly valuable applications for more accurate 3D vessel tracking and rendering.

• 제어로봇시스템학회논문지
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• 제5권3호
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• pp.275-280
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• 1999

This paper presents a disturbance accommodating sliding mode control for a quarter-car active suspension using an electro-hydraulic actuator. The electro-hydraulic actuator model is nonlinear and uncertain. The hardware constrains on the actuator prevent high gain in a sliding mode control, which deteriorates the force tracking performance. DAC(Disturbance Accommodating Control) is combined with the sliding mode control to improve the tracking performance. DAC observer estimates the pressure due to the actuator uncertainty. The additional control is designed to compensate the estimated pressure. Simulation results show the improved tracking performance with the Proposed control methods.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 신호처리소사이어티 추계학술대회 논문집
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• pp.445-448
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• 2003

In this paper, we present a hierarchical approach of an enhanced active shape model for video tracking. Kalman filter is used. To estimate a dynamic shape in video object tracking. The experimental results show that the proposed hierarchical active shape model using Kalman filter is efficient.

• Journal of Electrical Engineering and Technology
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• 제10권3호
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• pp.1275-1283
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• 2015

Markov chains for active tracking which assigns additional track illuminations evenly between search illuminations for a radar system are presented in this article. And some quantitative analyses on track formation range are discussed by using them. Compared with track-while-search (TWS) tracking that uses scan-to-scan correlation at search illuminations for tracking of a target, active tracking has shown the maximum improvement in track formation range of about 27.6%. It is also shown that the number and detection probability of additional track beams have impact on the track formation range. For the consideration of radar resource management at the preliminary radar system design stage, the presented analysis method can be used easily without the need of Monte Carlo simulation.

• 전기학회논문지
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• 제61권4호
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• pp.639-642
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• 2012

Optical coherence tomography(OCT) can provide real-time and non-invasive subsurface imaging with ultra-high resolution of micrometer scale. However, conventional OCT systems generally have a limited imaging depth range within a depth of only 1-2 mm. To overcome the limitation, we have proposed an active surface tracking algorithm used in common-path Fourier-domain OCT system in order to extend the imaging depth range. The surface tracking algorithm based on the threshold and Savitzky-Golay filter of A-scan data was applied to real-time tracking. The algorithm has controlled a moving stage according to the sample's surface variance in real time. An OCT image obtained by the algorithm clearly show an extended imaging depth range. Consequently, the proposed algorithm demonstrated the potential for improving the conventional OCT systems with limitary depth range.

• 반도체디스플레이기술학회지
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• 제10권1호
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• pp.83-89
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• 2011

In the case of the tracking system with an active camera, it is very difficult to guarantee real-time processing due to the attribute of vision system which handles large amounts of data at once and has time delay to process. The reliability of the processed result is also badly influenced by the slow sampling time and uncertainty caused by the image processing. In this paper, we figure out dynamic characteristics of pixels reflected on the image plane and derive the mathematical model of the vision tracking system which includes the actuating part and the image processing part. Based on this model, we find a controller that stabilizes the system and enhances the tracking performance to track a target rapidly. The centroid is used as the position index of moving object and the DC motor in the actuating part is controlled to keep the identified centroid at the center point of the image plane.

• International Journal of Precision Engineering and Manufacturing
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• 제7권1호
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• pp.47-50
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• 2006

An active contour model has been used to detect the edges in a still image. In order to apply the active contour model to edge detection, the energy function which consists of internal, external and image energies should be defined. After defining the energy function, the edge of an object is detected through minimization of the value of the energy function. In this paper, the modified internal energy function is proposed to improve the convergence of the energy function when the active contour model is applied to the tracking of deformable objects using the greedy algorithm. In order to show the performance of the proposed energy function, experiments were carried out for the still and animated images.

• 대한전자공학회논문지SP
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• 제41권5호
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• pp.23-34
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• 2004

본 논문에서는 사전학습이 필요 없는 능동 특징점 모델(non-prior training active feature model; NPT AFM) 기반에서 광류(optical flow)를 이용한 객체추적 기술을 제안한다. 제안한 알고리듬은 비정형 객체에 대한 분석[1]에 초점을 두고 있으며, 실시간에서 NPT-AFM을 사용한 강건한 추적을 가능하게 한다. NPT-AFM 알고리듬은 관심 객체의 위치를 파악하는 과정 (localization)과 이전 프레임 정보와 현재 프레임 정보를 이용하여, 객체의 위치를 예측(prediction), 보정(correction)하는 과정으로 나눌 수 있다 위치 파악 과정에서는 움직임 분할(motion segmentation)을 수행한 후 개선된 Shi-Tomasi의 특징점 추적 알고리듬[2]을 사용 하였다. 예측 및 보정 과정에서는 광류 정보를 사용하여 특징점을 추적하고[3] 만약, 특징점이 적절히 추적 되지 않거나 추적에 실패하면 특징점들의 시간(temporal), 공간(spatial)적 정보를 이용하여 예측, 보정하게 된다. 객체의 형태 (shape)대신 특징점을 사용하였으며, 객체를 추적하는 과정에서 특징점들은 능동 특징점 모델(active feature model; AFM)을 위한 학습 집합(training sets)의 요소로 갱신된다. 실험결과, 제안한 NPT-AF% 기반 추적 알고리듬은 실시간에서 비정형 객체를 추적하는데 강건함을 보석준다.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2009년도 추계학술대회 논문집
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• pp.375-378
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• 2009

This paper proposes active tracking algorithm to improve efficiency of PV system. Active tracking algorithm tracks sun position using sensor method and program method with insolation condition. Also, in this case that insolation is very low, tracking system is controlled by environment mode to reduce the power loss. Proposed algorithm is applied the PV system and analyzes the generation value. And this algorithm proves the validity of this pater through the experimental result.