• 대한기계학회논문집B
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• 제27권6호
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• pp.736-743
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• 2003

A process of 3-D particle image velocimetry, called here, as '3-D stereo PIV' was developed for the measurement of an illuminated slied section field of 3-D complex flows. The present method includes modeling of camera by a calibrator based on the homogeneous coordinate system, transfromation of the oblique-angled image to the right-angled image, identification of 2-D velocity vectors by 2-D cross-correlation equation, stereo matching of 2-D velocity vectors of two cameras, accurate calculation of 3-D velocity vectors by homogeneous coordinate system, removal of error vectors by a statistical method followed by a continuity equation criterior, and finally 3-D animation as the post processing. An experimental system was also used for the application of the proposed method. Three analog CCD cameras and an Argon-Ion Laser(300mW) for illumination were adopted to capture the wake flow behind a bluff obstacle.

• 한국생산제조학회지
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• 제8권6호
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• pp.26-34
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• 1999

This study shows an alternative method for the determination of object's position, based on a computer vision method. This approach develops the vision system model to define the reciprocal relationship between the 3-D real space and 2-D image plane. The developed model involves the bilinear six-view parameters, which is estimated using the relationship between the camera space location and real coordinates of known position. Based on estimated parameters in independent cameras, the position of unknown object is accomplished using a sequential estimation scheme that permits data of unknown points in each of the 2-D image plane of cameras. This vision control methods the robust and reliable, which overcomes the difficulties of the conventional research such as precise calibration of the vision sensor, exact kinematic modeling of the robot, and correct knowledge of the relative positions and orientation of the robot and CCD camera. Finally, the developed vision control method is tested experimentally by performing determination of object position in the space using computer vision system. These results show the presented method is precise and compatible.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2009년도 IWAIT
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• pp.290-293
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• 2009

In this paper, we propose a method to estimate pointing region in real-world from images of cameras. In general, arm-pointing gesture encodes a direction which extends from user's fingertip to target point. In the proposed work, we assume that the pointing ray can be approximated to a straight line which passes through user's face and fingertip. Therefore, the proposed method extracts two end points for the estimation of pointing direction; one from the user's face and another from the user's fingertip region. Then, the pointing direction and its target region are estimated based on the 2D-3D projective mapping between camera images and real-world scene. In order to demonstrate an application of the proposed method, we constructed an ICGS (interactive cinema guiding system) which employs two CCD cameras and a monitor. The accuracy and robustness of the proposed method are also verified on the experimental results of several real video sequences.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.658-663
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• 2003

A process of 3-D stereo particle image velocimetry(PIV)was developed for the measurement of an illuminated sliced section field of 3-D complex flows. The present method includes modeling of camera by a calibrator based on the homogeneous coordinate system, transformation of the oblique-angled image to the right-angled image, identification of 2-D velocity vectors by 2-D cross-correlation equation, stereo matching of 2-D velocity vectors of two cameras, accurate calculation of 3-D velocity vectors by homogeneous coordinate system, removal of error vectors by a statistical method followed by a continuity equation criteria, and finally 3-D display as the post processing. An experimental system was also used for the application of the proposed method. Two high speed digital CCD cameras and an Argon-Ion Laser for the illumination were adopted to clarify the time-dependent characteristics of the leading edge extension(LEX) in a highly swept shape applied to a delta wing found in modern air-fighters.

• Journal of Biosystems Engineering
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• 제25권5호
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• pp.415-420
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• 2000

It is very difficult to mechanize tomato harvesting because identifying a target tomato which is partly covered by leaves and stalks is not easy. This research was conducted to develop tomato harvesting robot which can identifying a target tomato, determining its dimensional position, and harvesting it in a limited time. Followings were major findings in this study. The first visual system of the robot was composed of two CCD cameras, however, which could not detect tomato not placed on the center of lens and partly covered by leaves or stalks. Secondary visual device, combined with two cameras and pan tilting was designed which could decreased the positioning errors within $\pm$10mm but still not enough for covered tomato by any obstacles. Finally, laser detector was added to the visual system that could reduce the position detecting errors within 10mm in X-Y direction and 5mm in Z direction for the covered tomatoes.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2002년도 추계학술대회 논문집
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• pp.19-22
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• 2002

A process of 3-D particle image velocimetry, called here, as '3-D stereo PIV' was developed for the measurement of a section field of 3-D complex flows. The present method includes modeling of camera by a calibrator based on the homogeneous coordinate system, transfromation of oblique-angled image to transformed image, identification of 2-D velocity vectors by 2-D cross-correlation equation, stereo matching of 2-D velocity vectors of two cameras, accurate calculation of 3-D velocity vectors by homogeneous coordinate system and finally 3-D animation as the post processing. In principle, as two frame images only are necessary for the single instantaneous analysis of a section field of 3-D flow, more effective vectors are obtainable contrary to the previous multi-frame vector algorithm. An experimental system was also used for the application of the proposed method. Three analog CCD cameras and an Argon-Ion Laser(300mW) for illumination were adopted to capture the wake flow behind a bluff obstacle.

• 한국항행학회논문지
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• 제9권1호
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• pp.48-55
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• 2005

본 논문에서는 다중 카메라 감시 시스템에서의 효율적인 이동물체 추적기법을 제안한다. 시스템에 사용된 컬러 CCD 카메라는 고유의 IP를 할당받는 네트워크 카메라이며, 입력영상은 미디어 서버와 브릿지, 그리고 AP(Access Point)와의 무선통신을 통해 전송된다. 감시시스템은 네트워크를 통해 전송된 영상을 트래킹 모듈에 전달하게 되며, 컬러 매칭 기법을 이용하여 이동물체를 실시간으로 추적한다. 두 개의 트래킹 세트를 구성하여 이동물체가 특정 카메라의 FOV(Field of view)를 벗어날 경우, 카메라 간에 핸드 오버가 가능케 함으로써 계속해서 이동물체를 추적하도록 한다. 핸드 오버 발생시에 타깃이 되는 정확한 이동물체 추적을 위하여 배경 정보 처리와 컬러 정보를 이용한 MHI(Motion History Information)와 M-bin histogram 기법을 제안한다. MHI를 이용하여 이동물체의 운동방향과 속도를 계산해 낼 수 있으며, 이러한 정보를 바탕으로 예상 이동위치를 판단할 수 있다. MHI를 이용한 결과, 단순히 M-bin histogram 기법을 이용하여 템플릿 매칭을 했을 경우 보다 속도와 안정성에 있어서 성능 향상을 가져옴을 실험을 통해 확인할 수 있었다.

• 전자공학회논문지S
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• 제35S권8호
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• pp.1-11
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• 1998

차세대 정보 통신 서비스의 고도화를 위해 추구되는 핵심 기술 중의 하나가 가시화를 통한 실감(Sensation of Reality) 서비스의 구현이다. 정보 통신 서비스의 가시화를 통한 실감화는 3차원 동영상 통신 기술의 개발없이는 구현이 불가능하다. 3차원 동영상 통신의 구현에 있어 가장 큰 문제점은 3차원 동영상에 포함된 많은 정보량을 전송할 수 있는 전송 기술과 3차원 영상을 촬영하고 실시간으로 표시할 수 있는 기술이 아직 확립되어 있지 않다는 것이다. 현재 확립되어 있는 3차원 동영상 기술은 주로 입체 방식(Stereoscopic Type)으로 실감을 얻기가 어렵다. 입체영상 보다 실감을 더해 주는 영상은 눈의 움직임과 함께 입체 영상이 연속적으로 변하게 하는 다시점(Multiview) 3차원 영상이다. 다시점 3차원 영상시스템을 8대의 카메라와 빔 프로젝터 그리고 홀로그래픽 스크린을 이용하는 시분할(Time Multiplexing) 방식에 의해 구현했다. 이 시스템에서 다시점 영상은 8대의 카메라에 의해 촬영되며, 이 촬영된 영상은 신호변환기에 의해 색상별로 한 개의 채널로 합성되어 초당 480 프레임 주파수로 빔 프로젝터에 의해 홀로그래픽 스크린에 투사된다. 빔 프로젝터의 영상은 띠형(Strip Type) 액정 셔터를 통해 홀로그래픽 스크린에 투사되게 되며, 이 띠형 액정 셔터는 홀로그래픽 스크린상에 투사된 영상을 볼 수 있게 시역을 형성한다. 각 카메라는 대응하는 띠형 액정 셔터들과 동기되어 움직이므로, 각 카메라의 영상은 대응하는 액정 셔터를 통해 투사하게 되어 시역에서는 다시점 3차원 영상의 시청이 가능해진다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2008년도 춘계종합학술대회 A
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• pp.877-881
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• 2008

In this paper, we propose a real-time people tracking system with multiple CCD cameras for security inside the building. The camera is mounted from the ceiling of the laboratory so that the image data of the passing people are fully overlapped. The implemented system recognizes people movement along various directions. To track people even when their images are partially overlapped, the proposed system estimates and tracks a bounding box enclosing each person in the tracking region. The approximated convex hull of each individual in the tracking area is obtained to provide more accurate tracking information. To achieve this goal, we propose a method for 3D walking human tracking based on the IMPRESARIO framework incorporating cascaded classifiers into hypothesis evaluation. The efficiency of adaptive selection of cascaded classifiers have been also presented. We have shown the improvement of reliability for likelihood calculation by using cascaded classifiers. Experimental results show that the proposed method can smoothly and effectively detect and track walking humans through environments such as dense forests.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2004년도 학술대회지
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• pp.274-278
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• 2004

A simultaneous measurement system that can analyze the flaw-structure interactions has been developed This system consists of four CCD cameras, two for capturing instantaneous flaw fields and two for tracking a solid body. The three-dimensional vector fields around a cylinder are measured while the motion of the cylinder forced by the flow field is measured simultaneously with the constructed system The cylinder is pended in the working fluid of a water channel and the surface of the working fluid is forced sinusoidal to make the cylinder bounced Reynolds number for the mean main stream is about l000. The interaction between the flaw fields and the cylinder motion is examined quantitatively.