• 한국산업융합학회 논문집
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• 제18권2호
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• pp.82-89
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• 2015

This study proposes a new approach to design and control for autonomous mobile robots. In this paper, we describes a fuzzy logic based visual servoing system for an autonomous mobile robot. An existing system always needs to keep a moving object in overall image. This mes difficult to move the autonomous mobile robot spontaneously. In this paper we first explain an autonomous mobile robot and fuzzy logic system. And then we design a fuzzy logic based visual servoing system. We extract some features of the object from an overall image and then design a fuzzy logic system for controlling the visual servoing system to an exact position. We here introduce a shooting robot that can track an object and hit it. It is illustrated that the proposed system presents a desirable performance by a computer simulation and some experiments.

• 한국철도학회논문집
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• 제8권4호
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• pp.330-336
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• 2005

This paper presents a development of the control and the virtual reality visual system for a tilting train simulator. The user of the tilting train simulator is able to set up the environmental and operating conditions through the user interface provided by the control system. In the control system, an arbitrary track which has user-defined curve radius, length and direction can be generated. The virtual reality visual system provides an artificial environment that is composed of several facilities such as station, platform, track, bridge, tunnel and signaling system. In order to maximize the reality, all of the 3D modeling were based on the real photographs taken in the Jungang line. A dome screen with 1600mm diameter was used to maximize the view angle. The hemispherical screen can ensure the view angle of the 170 degrees of vertical direction and 135 degrees of lateral direction.

• 한국정밀공학회지
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• 제16권8호
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• pp.113-121
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• 1999

It is necessary to calibrate measurement systems to enhance its measurement accuracy. The visual sensing system that is presented in our previous work has to be calibrated, too. It is a multiple mirror system for three-dimensional measurement, which is composed of a camera and a series of mirrors. It is important to calibrate the positions and orientations of the mirrors relative to the camera because they have direct influence on the relationship between the image plane and the task space. This paper presents the calibration method for the visual sensing system. To confirm the measurement performance of the implemented system. its measurement accuracy in measuring the locations in three-dimensional space is investigated. A series of experiments for measuring the locations of the circle-shaped marks are performed. Experimental results show that the sensing system can be effectively used for three-dimensional measurement.

• 융합신호처리학회논문지
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• 제11권4호
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• pp.303-309
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• 2010

본 논문에서는 KS 표준 시표(Optotype)를 이용한 자가 시력 측정의 새로운 방법을 제안한다. 제안한 시스템은 시력 측정 응답에 있어서 피검자 편의성을 위한 피검사자의 손-동작 인식(Hand-Gesture Recognition) 방법을 제공한다. 또한 검사자가에 필요 없는 컴퓨터에 의한 무작위 자동 시표 조정으로 검사자의 주관적인 판단이나 피검자의 암기에 의한 추측이 배제된 객관적 시력 측정이 가능하다. 특히, 2006년에 한국 표준 협회에서 정의한 표준 시표와 그 제시법(KS P ISO 8596)에 따라 시스템을 구현함으로써 시스템에 대한 신뢰성이 보장되고, 측정된 시력 정보의 데이터베이스 관리 기능은 피검자의 시력 정보가 필요한 전자의료기록(EMR) 시스템을 위한 전자 정보 전달이 용이하다. 구현된 시력 측정 시스템은 피검자를 대상으로 실제 시력표를 이용하여 측정한 방법과 비교 실험한 결과, 오차한계 ${\pm}1$ 시력등급 내에서 98%의 정확성을 보였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.767-771
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• 2003

In this study, stereo vision system is applied to a mobile manipulator for effective tasks. The robot can recognize a target and compute the position of the target using a stereo vision system. While a monocular vision system needs properties such as geometric shape of a target, a stereo vision system enables the robot to find the position of a target without additional information. Many algorithms have been studied and developed for an object recognition. However, most of these approaches have a disadvantage of the complexity of computations and they are inadequate for real-time visual servoing. However, color information is useful for simple recognition in real-time visual servoing. In this paper, we refer to about object recognition using colors, stereo matching method, recovery of 3D space and the visual servoing.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.1327-1330
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• 2004

An underwater robotic system has been developed and applied to visual inspection of reactor vessel internals. The Korea Electric Power Robot for Visual Test (KeproVt) consists of an underwater robot, a vision processor-based measuring unit, a master control station and a servo control station. The robot guided by the control station with the measuring unit can be controlled to have any motion at any position in the reactor vessel with $\pm$1 cm positioning and $\pm$2 degrees heading accuracies with enough precision to inspect reactor internals. A simple and fast installation process is emphasized in the developed system. The developed robotic system was successfully deployed at the Younggwang Nuclear Unit 1 for the visual inspection of reactor internals.

• 제어로봇시스템학회논문지
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• 제11권5호
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• pp.411-417
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• 2005

In this study, stereo vision system is applied to a mobile manipulator for effective tasks. The robot can recognize a target and compute the potion of the target using a stereo vision system. While a monocular vision system needs properties such as geometric shape of a target, a stereo vision system enables the robot to find the position of a target without additional information. Many algorithms have been studied and developed for an object recognition. However, most of these approaches have a disadvantage of the complexity of computations and they are inadequate for real-time visual servoing. Color information is useful for simple recognition in real-time visual servoing. This paper addresses object recognition using colors, stereo matching method to reduce its calculation time, recovery of 3D space and the visual servoing.

• 정보통신설비학회논문지
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• 제10권3호
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• pp.103-109
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• 2011

With the growing popularity of digital video applications, those areas of the efficient transmit, storage management, and search technology for video data are emerging as an important core technology. To be an effective video indexing system, users need to be able to find the video segments that they want. Unfortunately, video data is difficult to manage because of its unstructured data type and large volume with linear forms. This paper proposes a shot verification using visual rhythm and video retrieval system. The shot verification is designed to detect a segment from video easily and quickly, known as shot boundaries, just by changing the visual rhythm without playing the image. Therefore, this can decrease the false detected shots and generate the unidentified shots and key frames. The retrieval system is constructed in terms of visual descriptor from the list of MPEG-7. The effectiveness of the proposed shot verification process and video retrieval system is demonstrated.

• 동력기계공학회지
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• 제6권1호
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• pp.96-101
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• 2002

In this paper, we address the problem of controlling an end-effector to track and grab a moving target using the visual servoing technique. A visual servo mechanism based on the image-based servoing principle, is proposed by using visual feedback to control an end-effector without calibrated robot and camera models. Firstly, we consider the control problem as a nonlinear least squares optimization and update the joint angles through the Taylor Series Expansion. And to track a moving target in real time, the Jacobian estimation scheme(Dynamic Broyden's Method) is used to estimate the combined robot and image Jacobian. Using this algorithm, we can drive the objective function value to a neighborhood of zero. To show the effectiveness of the proposed algorithm, simulation results for a six degree of freedom robot are presented.

• 대한의용생체공학회:의공학회지
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• 제17권4호
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• pp.417-426
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• 1996

In this paper, we report the effects of visual stimulation patterns in the postural balance control. We used the motor-driven cloth panel and HMD(Head Mounted Display) to evaluate the effect of visual stimulation patterns in the postural balance control. We also investigated the usefulness of HMD in the postural balance rehabilitation training system from the view of reducing the scale of experimental system. Our results showed that a vertical-strip visual pattern was more effective than the others in the postural balance control. It was also indicated that HMD might be applied to clinical use as a new postural balance training system.