• Title/Summary/Keyword: User tracking

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Robust Multithreaded Object Tracker through Occlusions for Spatial Augmented Reality

  • Lee, Ahyun;Jang, Insung
    • ETRI Journal
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    • v.40 no.2
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    • pp.246-256
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    • 2018
  • A spatial augmented reality (SAR) system enables a virtual image to be projected onto the surface of a real-world object and the user to intuitively control the image using a tangible interface. However, occlusions frequently occur, such as a sudden change in the lighting environment or the generation of obstacles. We propose a robust object tracker based on a multithreaded system, which can track an object robustly through occlusions. Our multithreaded tracker is divided into two threads: the detection thread detects distinctive features in a frame-to-frame manner, and the tracking thread tracks features periodically using an optical-flow-based tracking method. Consequently, although the speed of the detection thread is considerably slow, we achieve real-time performance owing to the multithreaded configuration. Moreover, the proposed outlier filtering automatically updates a random sample consensus distance threshold for eliminating outliers according to environmental changes. Experimental results show that our approach tracks an object robustly in real-time in an SAR environment where there are frequent occlusions occurring from augmented projection images.

Polishing Robot Attached to a Machining Center for a Freely-Curved Surface Die

  • Lee, Min-Cheol;Go, Seok-Jo;Cho, Young-Gil;Lee, Man-Hyung
    • International Journal of Precision Engineering and Manufacturing
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    • v.3 no.4
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    • pp.43-53
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    • 2002
  • Polishing a die that has free-form surfaces is a time-consuming and tedious job, and requires a considerable amount of high-precision skill. In order to reduce the polishing time and cope with the shortage of skilled workers, a user-friendly automatic polishing system was developed. The polishing system is composed of two subsystems, a three-axis machining center and a two-axis polishing robot. The system has five degrees of freedom and is able to keep the polishing tool in a position normal to the die surface during operation. A sliding mode control algorithm with velocity compensation was proposed to reduce tracking errors. Trajectory tracking experiments showed that the tracking error can be reduced prominently by the proposed sliding mode control compared to a PD (proportional derivative) control. To evaluate the polishing performance of the polishing system and to and the optimal polishing conditions, the polishing experiments were conducted.

Development of Requirements Tracking and Verification System for the Software Design of Distributed Control System

  • Jung, Chul-Hwan;Kim, Jang-Yeol;Kim, Jung-Tack;Lee, Jang-Soo;Ham, Chang-Shik
    • Proceedings of the Korean Nuclear Society Conference
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    • 1998.05a
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    • pp.335-340
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    • 1998
  • In this paper a prototype of Requirement Tracking and Verification System(RTVS) for a Distributed Control System was implemented and tested. The RTVS is a software design and verification tool. The main functions required by the RTVS are managing, tracking and verification of the software requirements listed in the documentation of the DCS. The analysis of DCS software design procedures and inter(aces with documents were performed to define the user of the RTVS, and the design requirements for RTVS were developed.

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An Adaptive Approach to Learning the Preferences of Users in a Social Network Using Weak Estimators

  • Oommen, B. John;Yazidi, Anis;Granmo, Ole-Christoffer
    • Journal of Information Processing Systems
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    • v.8 no.2
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    • pp.191-212
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    • 2012
  • Since a social network by definition is so diverse, the problem of estimating the preferences of its users is becoming increasingly essential for personalized applications, which range from service recommender systems to the targeted advertising of services. However, unlike traditional estimation problems where the underlying target distribution is stationary; estimating a user's interests typically involves non-stationary distributions. The consequent time varying nature of the distribution to be tracked imposes stringent constraints on the "unlearning" capabilities of the estimator used. Therefore, resorting to strong estimators that converge with a probability of 1 is inefficient since they rely on the assumption that the distribution of the user's preferences is stationary. In this vein, we propose to use a family of stochastic-learning based Weak estimators for learning and tracking a user's time varying interests. Experimental results demonstrate that our proposed paradigm outperforms some of the traditional legacy approaches that represent the state-of-the-art technology.

Interactive visual knowledge acquisition for hand-gesture recognition (손 제스쳐 인식을 위한 상호작용 시각정보 추출)

  • 양선옥;최형일
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.33B no.9
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    • pp.88-96
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    • 1996
  • Computer vision-based gesture recognition systems consist of image segmentation, object tracking and decision. However, it is difficult to segment an object from image for gesture in computer systems because of vaious illuminations and backgrounds. In this paper, we describe a method to learn features for segmentation, which improves the performance of computer vision-based hand-gesture recognition systems. Systems interact with a user to acquire exact training data and segment information according to a predefined plan. System provides some models to the user, takes pictures of the user's response and then analyzes the pictures with models and a prior knowledge. The system sends messages to the user and operates learning module to extract information with the analyzed result.

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Dynamic Adaptive Model based on Probabilistic Distribution Functions and User's Profile for Web Media Systems (웹 미디어 시스템을 위한 확률 분포 함수와 사용자 프로파일에 기반 한 동적 적응 모델)

  • Baek, Yeong-Tae;Lee, Se-Hoon
    • The Journal of Korean Association of Computer Education
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    • v.6 no.1
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    • pp.29-39
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    • 2003
  • In this paper we proposed dynamic adaptive model based on discrete probabilistic distribution functions and user's profile for web media systems(web based hypermedia systems). The model represented that the application domain is modelled using a weighted direct graph and the user's behaviour is modelled using a probabilistic approach that dynamically constructs a discrete probability distribution functions. The proposed probabilistic interpretation of the web media structure is used to characterize latent properties of the user's behaviour, which can be captured by tracking user's browsing activity. Using that distribution the system attempts to assign the user to the best profile that fits user's expectations.

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WeWhere:A Multiple User Location Tracking System of Smart Phones (WeWhere:스마트 폰의 다중 사용자 위치 추적 시스템)

  • Park, Chan;Jeong, Ji-Seong;Yoo, Kwan-Hee
    • The Journal of the Korea Contents Association
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    • v.11 no.4
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    • pp.18-26
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    • 2011
  • According that smart phones have been widely used, their users can easily access various information around the devices through location information services equipped to the smart phone devices. In this paper, we propose a WeWhere which is a system of client-server model for providing the current location among several smart phone users in real time. A client-side smartphone user send to a server his/her current location obtained by applying location information service provided from smart phones and receive location information of all smartphone users connected to the user from the server. The all location information is displayed on a smartphone of a user in client-side and users can track location of their related users. All most 200,000 persons in the world have used the proposed system, WeWhere, normally without overloading of a server system.

Development of Real-Time Vision-based Eye-tracker System for Head Mounted Display (영상정보를 이용한 HMD용 실시간 아이트랙커 시스템)

  • Roh, Eun-Jung;Hong, Jin-Sung;Bang, Hyo-Choong
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.35 no.6
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    • pp.539-547
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    • 2007
  • In this paper, development and tests of a real-time eye-tracker system are discussed. The tracker system tracks a user's gaze point through movement of eyes by means of vision-based pupil detection. The vision-based method has an advantage of detecting the exact positions of user's eyes. An infrared camera and a LED are used to acquire a user's pupil image and to extract pupil region, which was hard to extract with software only, from the obtained image, respectively. We develop a pupil-tracking algorithm with Kalman filter and grab the pupil images by using DSP(Digital Signal Processing) system for real-time image processing technique. The real-time eye-tracker system tracks the movements of user's pupils to project their gaze point onto a background image.

Development and Evaluation of the V-Catch Vision System

  • Kim, Dong Keun;Cho, Yongjoo;Park, Kyoung Shin
    • Journal of the Korea Society of Computer and Information
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    • v.27 no.3
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    • pp.45-52
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    • 2022
  • A tangible sports game is an exercise game that uses sensors or cameras to track the user's body movements and to feel a sense of reality. Recently, VR indoor sports room systems installed to utilize tangible sports game for physical activity in schools. However, these systems primarily use screen-touch user interaction. In this research, we developed a V-Catch Vision system that uses AI image recognition technology to enable tracking of user movements in three-dimensional space rather than two-dimensional wall touch interaction. We also conducted a usability evaluation experiment to investigate the exercise effects of this system. We tried to evaluate quantitative exercise effects by measuring blood oxygen saturation level, the real-time ECG heart rate variability, and user body movement and angle change of Kinect skeleton. The experiment result showed that there was a statistically significant increase in heart rate and an increase in the amount of body movement when using the V-Catch Vision system. In the subjective evaluation, most subjects found the exercise using this system fun and satisfactory.

Implementation of Slaving Data Processing Function for Mission Control System in Space Center (우주센터 발사통제시스템의 추적연동정보 처리기능 구현)

  • Choi, Yong-Tae;Ra, Sung-Woong
    • Journal of Korea Society of Industrial Information Systems
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    • v.19 no.3
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    • pp.31-39
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    • 2014
  • In KSLV-I launch mission, real-time data from the tracking stations are acquired, processed and distributed by the Mission Control System to the user group who needed to monitor processed data for safety and flight monitoring purposes. The processed trajectory data by the mission control system is sent to each tracking system for target designation in case of tracking failure. Also, the processed data are used for decision making for flight termination when anomalies occur during flight of the launch vehicle. In this paper, we propose the processing mechanism of slaving data which plays a key role of launch vehicle tracking mission. The best position data is selected by predefined logic and current status after every available position data are acquired and pre-processed. And, the slaving data is distributed to each tracking stations through time delay is compensated by extrapolation. For the accurate processing, operation timing of every procesing modules are triggered by time-tick signal(25ms period) which is driven from UTC(Universial Time Coordinates) time. To evaluate the proposed method, we compared slaving data to the position data which received by tracking radar. The experiments show the average difference value is below 0.01 degree.