• 센서학회지
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• 제14권2호
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• pp.116-124
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• 2005

In this paper range measurement systems are designed using an ultrasonic sensor and a camera. An ultrasonic sensor provides the range measurement to a target quickly and simply but its low resolution is a disadvantage. We tackle this problem by employing a camera. Instead using a stereoscopic sensor, which is widely used for 3D sensing but requires a computationally intensive stereo matching, the range is measured by focusing and structured lighting. In focusing a straightforward focusing measure named as MMDH(min-max difference in histogram) is proposed and compared with existing techniques. In the method of structure lighting, light stripes projected by a beam projector are used. Compared to those using a laser beam projector, the designed system can be constructed easily in a low-budget. The system equation is derived by analysing the sensor geometry. A sensing scenario using the systems designed is in two steps. First, when better accuracy is required, measurements by ultrasonic sensing and focusing of a camera are fused by MLE(maximum likelihood estimation). Second, when the target is in a range of particular interest, a range map of the target scene is obtained by using structured lighting technique. The systems designed showed measurement accuracy up to 0.3[mm] approximately in experiments.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권1호
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• pp.378-390
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• 2015

Image projectors can turn any surface into a display. Integrating a surface projection with a user interface transforms it into an interactive display with many possible applications. Hand gesture interfaces are often used with projector-camera systems. Hand detection through color image processing is affected by the surrounding environment. The lack of illumination and color details greatly influences the detection process and drops the recognition success rate. In addition, there can be interference from the projection system itself due to image projection. In order to overcome these problems, a gesture interface based on depth images is proposed for projected surfaces. In this paper, a depth camera is used for hand recognition and for effectively extracting the area of the hand from the scene. A hand detection and finger tracking method based on depth images is proposed. Based on the proposed method, a touch interface for the projected surface is implemented and evaluated.

• 제어로봇시스템학회논문지
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• 제11권1호
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• pp.34-40
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• 2005

In this paper, we describe the modeling for the 3D robot laser scanning system consisting of a laser stripe projector, camera, and 5-DOF robot and propose its calibration method. Nonlinear radial distortion in the camera model is considered for improving the calibration accuracy. The 3D range data is calculated using the optical triangulation principle which uses the geometrical relationship between the camera and the laser stripe plane. For optimal estimation of the system model parameters, real-coded genetic algorithm is applied in the calibration process. Experimental results show that the constructed system is able to measure the 3D position within about 1mm error. The proposed scheme could be applied to the kinematically dissimilar robot system without losing the generality and has a potential for recognition for the unknown environment.

• 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.

• 서비스연구
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• 제5권1호
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• pp.45-55
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• 2015

공간증강현실(Spatial Augmented Reality, SAR) 기술은 초소형 프로젝터와 카메라로 구성되어 실제 사물을 인식하고, 물체 표면이나 주변에 상황에 적합한 정보 및 사용자 인터페이스를 투사(projection)하는 기술이며, 최근에는 소형 프로젝터의 등장으로 더욱 각광 받고 있는 기술이다. 본 논문에서는 공간증강현실 기술이 새로운 IT 패러다임으로 부각됨에 따라 이 기술을 이용하여 스탠드 형 모양에 프로젝터-카메라-프로세서를 설치하여 스마트 프로젝션(Smart Projection) 서비스 시스템을 구현하고, 적용한 서비스 구현사례를 소개 하고자 한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1990년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 26-27 Oct. 1990
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• pp.586-590
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• 1990

In this paper we describe the shape measuring technique and system with a non-contractive sensor, composed of slit-ray projector and solid-state camera. For improving the accuracy and preventing measuring dead point, this sensor part is attached to the end of robot, and each sensing is executed after one step moving. By patching these sensing data, whole measuring data is constructed. The calibration between sensor and world coordinate is implemented through the specific calibration block by transformation matrix method. The result of experiment was satisfactory.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2022년도 추계학술발표대회
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• pp.288-289
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• 2022

In this paper, we propose a method of obtaining high density geometric information using multi-view structured light. Reconstruction error due to the difference in resolution between the projector and the camera occurs when reconstruction a 3D shape from a structured light system to a single projector. This shows that the error in the point cloud in 3D is also the same when reconstruction the shape of the object. So we propose a high density method using multiple projectors to solve such a reconstruction error.

• 한국CDE학회논문집
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• 제19권4호
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• pp.356-367
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• 2014

A robotic sapatial augmented reality (RSAR) system, which combines robotic components with projector-based AR technique, is unique in its ability to expand the user interaction area by dynamically changing the position and orientation of a projector-camera unit (PCU). For a moving PCU mounted on a conventional robotic device, we can compute its extrinsic parameters using a robot kinematics method assuming a link and joint geometry is available. In a RSAR system based on user-created robot (UCR), however, it is difficult to calibrate or measure the geometric configuration, which limits to apply a conventional kinematics method. In this paper, we propose a data-driven kinematics control method for a UCR-based RSAR system. The proposed method utilized a pre-sampled data set of camera calibration acquired at sufficient instances of kinematics configurations in fixed joint domains. Then, the sampled set is compactly represented as a set of B-spline surfaces. The proposed method have merits in two folds. First, it does not require any kinematics model such as a link length or joint orientation. Secondly, the computation is simple since it just evaluates a several polynomials rather than relying on Jacobian computation. We describe the proposed method and demonstrates the results for an experimental RSAR system with a PCU on a simple pan-tilt arm.

• 한국정밀공학회지
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• 제32권7호
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• pp.633-641
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• 2015

In this study, we proposed a three-dimensional (3D) scanning system based on laser-vision technique and rotary mechanism for automatic 3D model reconstruction. The proposed scanning system consists of a laser projector, a camera, and a turntable. For laser-camera calibration a new and simple method was proposed. 3D point cloud data of the surface of scanned object was fully collected by integrating extracted laser profiles, which were extracted from laser stripe images, corresponding to rotary angles of the rotary mechanism. The obscured laser profile problem was also solved by adding an addition camera at another viewpoint. From collected 3D point cloud data, the 3D model of the scanned object was reconstructed based on facet-representation. The reconstructed 3D models showed effectiveness and the applicability of the proposed 3D scanning system to 3D model-based applications.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1994년도 Proceedings of the Korea Automatic Control Conference, 9th (KACC) ; Taejeon, Korea; 17-20 Oct. 1994
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• pp.561-565
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• 1994

An automatic measuring system of three dimensional shape by a projection method with grating pattern from in optical spatial modulator has been developed. The characteristics of the system were studied. This system is composed of a projector, an optical spatial modulator, a CCD camera, and computer. A liquid crystal is used as the optical spatial modulator. The grating patterns that ire projected on the surface of the object are controlled by the computer connected with the optical spatial modulator. The projector patterns are measured by the CCD camera. The data are transferred to the computer. After a transformation into line data, the data are analyzed to obtain the coordinate of the surface of the object. This system has advantages as follows. (1) It is possible to capture the surface topography without any contact. (2) The time required for the measurements is shorter than the light-section method. (3) An optical spatial modulator using a liquid crystal is possible to control the grating patterns accurately by a computer. Surfaces of a plate and a cylinder were measured. The threshold level had an influence on the measurement. It was shown that this system has adequae accuracy in the measurements.