• ICROS
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• v.19 no.4
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• pp.32-38
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• 2013

전방향 영상 시스템은 한 장의 영상에 360도 모든 방향의 영상정보를 담을 수 있는 영상획득 시스템을 의미한다. 기하광학소자를 이용하여 사람의 눈이나 기존의 카메라로는 한 번에 볼 수 없는 매우 넓은 범위의 영상데이터를 효율적으로 얻을 수 있다. 또한 전방향 영상획득의 원리와 시점이 다른 두 영상, 즉 스테레오 영상획득의 원리를 적용한 전방향 스테레오 영상 시스템은 두 영상간의 정합을 통해 3차원 거리를 측정할 수 있다는 특징이 있다. 본 고에서는 전방향 스테레오 영상획득에 관해 기존에 제안된 연구결과들의 광학적 원리와 장단점을 조사, 비교하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.6
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• pp.4108-4114
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• 2015

An image acquisition by using an optical mirror is called as a catadioptric method. The catadioptric imaging method is generally used for acquisition of 360-degree all directional visual information in an image. An exemplar omnidirectional optical mirror is the bowl-shaped hyperbolic mirror. In this paper, a single camera omnidirectional stereo imaging method is studied with an additional concave lens. It is possible to obtain 3 dimensional coordinates of environmental objects from the omnidirectional stereo image by matching the stereo image having different view points. The omnidirectional stereo imaging system in this paper is cost-effective and relatively easy for correspondence matching because of consistent camera intrinsic parameters in the stereo image. The parameters of the imaging system are extracted through 3-step calibration and the performance for 3-dimensional coordinates reconstruction is verified through experiments in this paper. Measurable range of the proposed imaging system is also presented by depth-resolution analysis.

• Journal of the Korean Institute of Intelligent Systems
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• v.24 no.4
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• pp.412-417
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• 2014

This paper presents the development and control of an omni-directional holonomic mobile robot platform, which is equipped with three lateral orthogonal-wheel assemblies. Omni-directionality can be achieved with decoupled rotational and translational motions. Simulation studies on collision avoidance are conducted. A real robot is built and its hardware is implemented to control the robot. Control algorithm is embedded on DSP and FPGA chips. Hardware for motor control such as PWM, encoder counter, serial communication modules is implemented on an FPGA chip. Experimental studies of following joystick commands are performed to demonstrate the functionality and controllability of the robot.

• 한국HCI학회:학술대회논문집
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• 2007.02a
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• pp.994-999
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• 2007

전방향(omnidirectional) 카메라 시스템은 보다 적은 수의 영상으로부터 주변 장면(scene)에 대한 많은 정보를 취득할 수 있는 장점이 있기 때문에 전방향 영상을 이용한 자동교정(self-calibration)과 3차원 재구성 등의 연구가 활발히 진행되고 있다. 본 논문에서는 기존에 제안된 교정 방법들을 이용하여 추정된 사영모델(projection model)의 정확성을 검증하기 위한 새로운 방법이 제안된다. 실 세계에서 다양하게 존재하는 직선 성분들은 전방향 영상에 컨투어(contour)의 형태로 사영되며, 사영모델과 컨투어의 양 끝점 좌표 값을 이용하여 그 궤적을 추정할 수 있다. 추정된 컨투어의 궤적과 영상에 존재하는 컨투어와의 거리 오차(distance error)로부터 전방향 카메라의 사영모델의 정확성을 검증할 수 있다. 제안된 방법의 성능을 평가하기 위해서 구 맵핑(spherical mapping)된 합성(synthetic) 영상과 어안렌즈(fisheye lens)로 취득한 실제 영상에 대해 제안된 알고리즘을 적용하여 사영모델의 정확성을 판단하였다.

• Journal of the Korean Institute of Intelligent Systems
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• v.23 no.2
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• pp.100-106
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• 2013

This paper presents design and control of an 'Omni-directional Cleaning Robot (OdCR)' which employs omni-wheels at three edges of its triangular configuration. Those omni-wheels enable the OdCR to move in any directions so that lateral movement is possible. For OdCR to be localized, a StarGazer sensor is used to provide accurate position and heading angle based on landmarks on the ceiling. In addition to that, ultrasonic sensors are installed to detect obstacles around OdCR's way. Experimental studies are conducted to test the functionality of the system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.5
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• pp.905-909
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• 2006

Recently various types of curved integral imaging system have been reported for improvement of viewing angle. However, the optical implementation has been limited to only unidirectional system. In this paper, we propose a curved integral imaging (CII) system with additional use of a large-aperture ten in conventional II system and explain a generation scheme of elemental images in the proposed system. The proposed system provides full-directional curvature effect and has simple structure due to the use of well-fabricated flat devices. For the full-directional-curved II system, we perform my analysis based on Johns matrix and synthesize novel elemental images. To show the usefulness of synthesized elemental images, preliminary experiments were performed and some experimental results were presented.

• The KIPS Transactions:PartC
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• v.14C no.2
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• pp.123-128
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• 2007

Many service systems use Public Key Infrastructure (PKI) to protect the service. But there arc problems with the use of PKI. One of the problems is that some services would require a function instantaneously to check public kel certificate, but PKI does not satisfy such request. To solve the problem, Bouch et al. first proposed the concept of mediated RSA (mRSA). Then Gene Tsudik proposed 'weak' forward secure mRSA. In this paper, we analyze the weakness of these schemes and find the source of the vulnerabilitv. And we propose a new mRSA that is strong forward secure.

• Journal of Broadcast Engineering
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• v.11 no.4 s.33
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• pp.396-406
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• 2006

This paper proposes an omni-directional image generation algorithm with parametric image compensation. The algorithm generates an omni-directional image by transforming each planar image to the spherical image on spherical coordinate. Parametric image compensation method is presented in order to compensate vignetting and illumination distortions caused by properties of a camera system and lighting condition. The proposed algorithm can generates realistic and seamless omni-directional video and synthesize any point of view from the stitched omni-directional image on the spherical image. Experimental results show that the proposed omni-directional system with vignetting and illumination compensation is approximately $1{\sim}4dB$ better than that which does not consider the said effects.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.4
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• pp.91-97
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• 2010

This paper describes a development of an network based remote surveillance system using omni-directional mobile robot. the proposed surveillance system can control a mobile robot to move and examines the given place closely while the conventional surveillance system uses a fixed camera. The mobile robot in the proposed system has three omni-directional wheels to move to any given direction freely. We also developed the proposed system as robot services using Microsoft's MSRDS for a user to control the mobile robot and monitor the remote scene captured from the robot. Finally we verified the feasibility and effectiveness of the proposed system by conducting the remote operating the mobile robot and monitoring experiments in a networked environment. We also conducted a color based object detection and motion detection on image sequences acquired from a remote mobile robot in an another PC in a network environment.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.23-23
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• 2004

이동로봇의 독립성과 움직임에 자유도를 높이기 위해서 축전지를 이동로봇에 탑재하고, 이를 이용하여 동력을 공급하는 경우가 대부분이다 이러한 경우에 에너지 효율은 제한된 동력을 가지는 시스템의 가동 가능시간을 결정하는 중요한 성능지수가 된다. 또한, 이동로봇의 최대속도나 최대가속도, 등판각도 등의 설계 사양을 소형의 모터를 사용하여 만족시키는 것은 이동로봇의 소형화, 경량화 및 시스템의 가격을 낮추기 위해 필수적이다. 그러나 이동로봇의 최대의 문제점 중의 하나인 소비전력의 감소에 대한 문제는 활발히 연구되고 있지 않다.(중략)