• 제어로봇시스템학회논문지
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• 제15권4호
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• pp.400-405
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• 2009

A new method for the catadioptric omnidirectional stereo vision with single camera is presented in this paper. The proposed method uses a concave lens with a convex mirror. Since the optical part of the proposed method is simple and commercially available, the resultant omnidirectional stereo system becomes versatile and cost-effective. The closed-form solution for 3D distance computation is presented based on the simple optics including the reflection and the reflection of the convex mirror and the concave lens. The compactness of the system and the simplicity of the image processing make the omnidirectional stereo system appropriate for real-time applications such as autonomous navigation of a mobile robot or the object manipulation. In order to verify the feasibility of the proposed method, an experimental prototype is implemented.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1055-1058
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• 2003

The robustness and reliability of vision algorithms is the key issue in robotic research and industrial applications. In this paper robust real time visual tracking in complex scene is considered. A common approach to increase robustness of a tracking system is the use of different model (CAD model etc.) known a priori. Also fusion or multiple features facilitates robust detection and tracking of objects in scenes of realistic complexity. Voting-based fusion of cues is adapted. In voting. a very simple or no model is used for fusion. The approach for this algorithm is tested in a 3D Cartesian robot which tracks a toy vehicle moving along 3D rail, and the Kalman filter is used to estimate the motion parameters. namely the system state vector of moving object with unknown dynamics. Experimental results show that fusion of cues and motion estimation in a tracking system has a robust performance.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 학술대회 논문집 정보 및 제어부문
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• pp.355-357
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• 2005

The distance between objects and a service robot can be measured by stereo vision system, but the two cameras need the same number of image grabber boards. In this paper, an approach to measure the distance is presented by using one camera which moves horizontally via motor position control. Images are captured at two different places where we know, and distance calculation is performed with the images and the camera position data. With a simple algorithm the proposed system requires only one image grabber board and no camera sequence controls are necessary, which resuces the system costs.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 D
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• pp.2444-2446
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• 2004

로봇 매니퓰레이터를 제어하기 위해서는 로봇의 Forward/Reverse Kinematics를 정확히 알아야 하고, 이를 바탕으로 각 목적에 맞는 로봇 매니퓰레이터의 설계가 이루어진다. 만약 이 매니퓰레이터에 카메라가 장치되어 어떤 물체를 추적해야 한다면, 매니퓰레이터의 Kinematics와 카메라의 컨트롤이 적절하게 조합되어 물체 추적을 행하게 된다. 본 논문에서는 Particle Filter의 큰 주류인 SISR 방법을 소개하고, 이 방법을 화상카메라에 적용하여 움직이는 물체를 추적하는 연구를 수행하려한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.63.6-63
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• 2001

For robot navigation and visual reconstruction , structure from motion (SFM) is an active issue in computer vision community and its properties are also becoming well understood. As a drawback in SFM, it is well known that the SFM methods, using small motion model such as optical flow and direct method, have inevitably motion ambiguity between translation and rotation, which is called bas-relief ambiguity. In this paper based on the robust direct method using stereo image sequence, we present a new method for improving those ambiguities. Basically, the direct method uses nearly all image pixels for estimating motion parameters and depths, and global optimization techniques are adopted for finding its solution ...

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.100.3-100
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• 2002

This paper presents the method for detection and tracking of multiple humans robustly in mobile platform. The perception of human is performed in real time through the processing of images acquired from a moving stereo vision system. We performed multi-cue integration such as human shape, skin color and depth information to detect and track each human in moving background scene. Human shape is measured by edge-based template matching on distance transformed image. Improving robustness for human detection, we apply the human face skin color in HSV color space. And we could increase the accuracy and the robustness in both detection and tracking by applying random sampling stochastic estimati...

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.97.4-97
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• 2002

1. Introduction Pose estimation of a three dimensional object has been studied in robot vision area, and it is needed in a number of industrial applications such as process monitoring and control, assembly and PCB inspection. In this research, we propose a new pose estimation method based on principal axes analysis. Here, it is assumed that the locations of x-ray source and the image plane are predetermined and the object geometry is known. To this end, we define a dispersion matrix of an object, which is a discrete form of inertia matrix of the object. It can be determined here from a set of x-ray images, at least three images are required. Then, the pose information is obtained fro...

• 대한임베디드공학회논문지
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• 제3권3호
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• pp.151-157
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• 2008

In this paper, we propose a three dimensional distance measurement method for a stereo system by using web cams. Using a parallel stereo system, a robot gets two images from each webcam and equalize brightness of both images. And we suggest an image processing method such as labeling, isolating an object from background and finding center of an object. We also propose a method of calculating the focal distance by using least square algorithm based on triangulation and we can reduce calculation error by this method. From experimental results, we show that the proposed method can be effective for 3D distance measurement.

• 제어로봇시스템학회논문지
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• 제13권3호
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• pp.224-229
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• 2007

This paper presents a camera calibration method using several images for three dimensional measurement applications such as stereo systems, mobile robots, and visual inspection systems in factories. Conventional calibration methods that use single image suffer from errors related to reference point extraction in image, lens distortion, and numerical analysis of nonlinear optimization. The camera parameter values obtained from images of same camera is not same even though we use same calibration method. The camera parameters that are obtained from several images of different view for a calibration target is usaully not same with large error values and we can not assume a special probabilistic distribution when we estimate the parameter values. In this paper, the median value of camera parameters from several images is used to improve estimation of the camera values in an iterative step with nonlinear optimization. The proposed method is proved by experiments using real images.

• 제어로봇시스템학회논문지
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• 제16권10호
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• pp.991-996
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• 2010

In this paper, a new indoor positioning system based on incident angle measurement of infrared sensor has been suggested. Though there have been various researches on indoor positioning systems using vision sensor or ultrasonic sensor, they have not only advantages, but also disadvantages. In a new positioning system, there are three infrared emitters on fixed known positions. An incident angle sensor measures the angle differences between each two emitters. Mathematical problems to determine the position with angle differences and position information of emitters has been solved. Simulations and experiments have been implemented to show the performance of this new positioning system. The results of simulation were good. Since there existed problems of noise and signal conditioning, the experimented has been implemented in limited area. But the results were acceptable. This new positioning method can be applied to any indoor systems that need absolute position information.