• Progress in Medical Physics
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• v.20 no.3
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• pp.174-179
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• 2009

To track moving tumor in real time, CyberKnife system imports a technique of the synchrony respiratory tracking system. The fiducial marker which are detectable in X-ray images were demand in CyberKnife Robotic radiosurgery system. It issued as reference markers to locate and track tumor location during patient alignment and treatment delivery. Fiducial marker implantation is an invasive surgical operation that carries a relatively high risk of pneumothorax. Most recently, it was developed a direct lung tumor registration method that does not require the use of fiducials. The purpose of this study is to measure the accuracy of target applying X-sight lung tracking using the Gafchromic film in dynamic moving thorax phantom. The X-sight Lung Tracking quality assurance motion phantom simulates simple respiratory motion of a lung tumor and provides Gafchromic dosimetry film-based test capability at locations inside the phantom corresponding to a typical lung tumor. The total average error for the X-sight Lung Tracking System with a moving target was $0.85{\pm}0.22$ mm. The results were considered reliable and applicable for lung tumor treatment in CyberKnife radiosurgery system. Clinically, breathing patterns of patients may vary during radiation therapy. Therefore, additional studies with a set real patient data are necessary to evaluate the target accuracy for the X-sight Lung Tracking system.

• Journal of Biomedical Engineering Research
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• v.44 no.1
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• pp.92-98
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• 2023

Purpose: To propose a new infusion rate monitoring technique based on the 2D image marker tacking to improve patient safety by preventing syringe pump-related medication accidents due to decreased infusion rate control accuracy. Materials and Methods: The infusion rate of the syringe pump and drug residue in the pump-equipped syringe were monitored in real time by tracking the movement of the 2D image markers attached to the syringe pump. Results: The error rate between the set and the estimated infusion rates was 1.03, 0.66, 1.95, 0.23, and 1.05% when the infusion rate setting was 10, 20, 30, 40, and 50 mL/H, respectively. In addition, the error rate between the actual and the estimated drug residues was 1.04, 0.47, 0.60, 3.66, and 0.00% when the infusion rate setting was 10, 20, 30, 40, and 50 mL/H, respectively. Conclusion: Experimental results demonstrated that the proposed technique can increase the efficiency of the safety management system for seriously ill inpatients by decreasing a possibility of syringe pump-related medication accidents in hospitals.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.7 no.6
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• pp.897-906
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• 2017

Projection Mapping, also known as Spatial Augmented Reality(SAR) has attracted much attention recently and used for many division, which can augment physical objects with projected various virtual replications. However, conventional approaches towards projection mapping have faced some limitations. Target objects' geometric transformation property does not considered, and movements of flexible objects-like paper are hard to handle, such as folding and bending as natural interaction. Also, precise registration and tracking has been a cumbersome process in the past. While there have been many researches on Projection Mapping on static objects, dynamic projection mapping that can keep tracking of a moving flexible target and aligning the projection at interactive level is still a challenge. Therefore, this paper propose a new method using Unity3D and ARToolkit for high-speed robust tracking and dynamic projection mapping onto non-rigid deforming objects rapidly and interactively. The method consists of four stages, forming cubic bezier surface, process of rendering transformation values, multiple marker recognition and tracking, and webcam real time-lapse imaging. Users can fold, curve, bend and twist to make interaction. This method can achieve three high-quality results. First, the system can detect the strong deformation of objects. Second, it reduces the occlusion error which reduces the misalignment between the target object and the projected video. Lastly, the accuracy and the robustness of this method can make result values to be projected exactly onto the target object in real-time with high-speed and precise transformation tracking.

• The Journal of the Korea Contents Association
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• v.11 no.5
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• pp.32-40
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• 2011

The tracking and analysis of cell activities in time-lapse sequences plays an important role in understanding complex biological processes such as the spread of the tumor, an invasion of the virus, the wound recovery and the cell division. For automatic tracking of cells, the tasks such as the cell detection at each frame, the investigation of the correspondence between cells in previous and current frames, the identification of the cell division and the recognition of new cells must be performed. This paper proposes an automatic cell tracking algorithm. In the first frame, the marker of each cell is extracted using the feature vector obtained by the analysis of cellular regions, and then the watershed algorithm is applied using the extracted markers to produce the cell segmentation. In subsequent frames, the segmentation results of the previous frame are incorporated in the segmentation process for the current frame. A combined criterion of geometric and intensity property of each cell region is used for the proper association between previous and current cells to obtain correct cell tracking. Simulation results show that the proposed method improves the tracking performance compared to the tracking method in Cellprofiler (the software package for automatic analysis of bioimages).

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.8
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• pp.579-584
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• 2016

When surgical instruments are tracked in an image-guided surgical navigation system, a stereo vision system with high accuracy is generally used, which is called optical tracker. However, this optical tracker has the disadvantage that a line-of-sight between the tracker and surgical instrument must be maintained. Therefore, to complement the disadvantage of optical tracking systems, an internal vision sensor is attached to a surgical instrument in this paper. Monitoring the target marker pattern attached on patient with this vision sensor, this surgical instrument is possible to be tracked even when the line-of-sight of the optical tracker is occluded. To verify the system's effectiveness, a series of basic experiments is carried out. Lastly, an integration experiment is conducted. The experimental results show that rotational error is bounded to max $1.32^{\circ}$ and mean $0.35^{\circ}$, and translation error is in max 1.72mm and mean 0.58mm. Finally, it is confirmed that the proposed tool tracking method using an internal vision sensor is useful and effective to overcome the occlusion problem of the optical tracker.

• The Journal of the Korea Contents Association
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• v.10 no.5
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• pp.20-28
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• 2010

In this paper, we propose a hand gesture interface for the manipulation of augmented objects in 3D space using a camera. Generally a marker is used for the detection of 3D movement in 2D images. However marker based system has obvious defects since markers are always to be included in the image or we need additional equipments for controling objects, which results in reduced immersion. To overcome this problem, we replace marker by planar hand shape by estimating the hand pose. Kalman filter is for robust tracking of the hand shape. The experimental result indicates the feasibility of the proposed algorithm for hand based AR interfaces.

• Smart Structures and Systems
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• v.31 no.6
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• pp.573-583
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• 2023

Although unmanned aerial vehicles have been used to overcome the limited accessibility of human-based visual inspection, unresolved issues still remain. Onsite inspectors face difficulty finding previously detected damage locations and tracking their status onsite. For example, an inspector still marks the damage location on a target structure with chalk or drawings while comparing the current status of existing damages to their previous status, as documented onsite. In this study, an augmented-reality-based structural inspection system with onsite damage information marking was developed to enhance the convenience of inspectors. The developed system detects structural damage, creates a holographic marker with damage information on the actual physical damage, and displays the marker onsite via an augmented reality headset. Because inspectors can view a marker with damage information in real time on the display, they can easily identify where the previous damage has occurred and whether the size of the damage is increasing. The performance of the developed system was validated through a field test, demonstrating that the system can enhance convenience by accelerating the inspector's essential tasks such as detecting damages, measuring their size, manually recording their information, and locating previous damages.

• Journal of the HCI Society of Korea
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• v.2 no.2
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• pp.11-18
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• 2007

We propose a novel method to conceal fiducial markers observed in augmented scenes using patch-based texture synthesis. Despite the efficiency for simple object recognition and tracking, the markers deliver inherent obtrusiveness. They do not only reduce immersiveness, but also severely degrade usability of augmented reality. The proposed method constructs alternative images in real time to overlay markers present in the sequence of images. The global characteristics of background textures are retained and the results are more adaptive to illumination changes.

• Journal of the Ergonomics Society of Korea
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• v.16 no.3
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• pp.71-75
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• 1997

This paper presents the development of videobased 3-dimensional tracking system. Measurement of human motion is important in the application of ertonomics. The system uses advanced direct video measurement technology. Passive retro-reflecting markers are attached to a subject and movements of markers are observed by two CCD cameras. Infrared light emitted near the CCD cameras is reflected by the markers and is detected by the cameras. The images are captured by Samsung MVB302 board and the centers of markers are calculated by DSP program. The positions of markers are transferred from MVB02 board to the computer through AT bus. The computer then tracks the position of each marker and saves the data. This system has dynamic accuracy with 0.7% average error and 4.2% maximum error, and the sampling rate to 6 .approx. 10 Hz, and this system can analyse the trajectory and speed of the marker. The results of this study can be used for operator's motion analysis, task analysis, and hand movement characteristic analysis.

• 한국HCI학회:학술대회논문집
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• 2007.02a
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• pp.131-136
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• 2007

본 논문에서는 모바일 증강현실에서 스마트 오브젝트 인식 및 트래킹을 위한 임베디드 마커 시스템을 제안한다. 기존의 증강 현실 연구에서 주로 사용하는 마커는 임의의 패턴을 포함하고 대상 오브젝트와는 분리되어 있다. 이는 부자연스러운 시각적 장애 요인으로 작용한다. 또한 특정한 마커를 사용하기 위해 학습 과정을 거친 후 그 결과를 인식 모듈에서 일일이 등록해야 하는 번거로움이 있다. 이러한 문제점을 해결하기 위해 제안하는 임베디드 마커는 디스플레이 장치의 유무에 따라 고정형 또는 가변 형으로 분류된 스마트 오브젝트의 특성을 고려하여 오브젝트와 마커를 결합한다. 또한 통합된 학습과 인식 모듈을 통해 오브젝트의 추가 및 시스템 확장을 용이하게 한다. 제안된 시스템은 스마트 홈 테스트베드인 ubiHome 에 적용되었다. 또한 사용 성 평가를 통해 그 효용성을 분석하였다. 이러한 임베디드 마커를 사용하면 사용자는 보다 직관적으로 마커의 용도를 예측할 수 있고 대상물과의 시선을 일치시켜 자연스러운 증강현실을 경험할 수 있을 것으로 기대된다.