• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.100.2-100
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• 2002

In this paper we propose a new visual servoing method for door opening with mobile manipulator. We use an eye-to-hand system that stereo camera is mounted on mobile platform, and adopt the position-based method. The previous methods for door opening mostly used eye-in-hand system with mono camera and required predefined knowledge such as radius and position about door grip, which was mainly caused by using mono cam era. This is also a severe constraint for pursuing general-purpose algorithm for door opening. For overcoming such drawback, we use stereo camera and suggest a new method that detect the door grip and estimate its pose from stereo depth information without predefined knowledge. Al...

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.11
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• pp.955-959
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• 2013

It is possible to obtain an omnidirectional stereo image via a single camera by using a catadioptric approach with a convex mirror and concave lens. In order to measure three-dimensional distance using the imaging system, the optical parameters of the system are required. In this paper, a calibration procedure to extract the parameters of the imaging system is described. Based on the parameters, experiments are carried out to verify the performance of the three-dimensional distance measurement of a single camera omnidirectional stereo imaging system.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.10
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• pp.50-62
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• 1996

A parallel looking stereo camera was mainly used as an input sensor for digital image processing, image understanding and the extraction of 3 dimensional information. Theoretical analysis and performance evaluation are dealt in this paper for a convergent looking stereo camera model having a fixation point with the result of crossing optical axes. The quantization error, depth resolution and equidepth map due to digital pixels, and the misalignments effects of pan, tilt and roll angles are analyzed by using rhe relationship between the reference and image coordinate systems. Also horopter, epipolar lines, probability density functions of the depth error, and stereo fusion areas for the two camera models are discussed.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.4
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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.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1997.03a
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• pp.207-212
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• 1997

In estimating the formability of sheet metal, the stereo vision system contributes the accuracy of strain of sheet metal, the convenience in measuring the strain of sheet metal, and the handiness in preparing the forming limit diagram by calculating the 3D values and strain of sheet metal. The algorithm has been developed so that the 3D-coordinate values of sheet metal could be calculated by image processing which is composed of camera calibration, and the stereo matching of images in two viewpoints. By comparing with experiments, the possibility and the convenience of algorithm has been verified, which could calculate the 3D-coordinate values of sheet metal automatically by using the preprocessing of the original image of sheet metal, which had the noise before adjusting the camera calibration and the stereo matching algorithm.

• Journal of Welding and Joining
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• v.19 no.2
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• pp.200-207
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• 2001

Three-diemnsional bead profile was measured using the biprism stereo vision sensor in GMAW, which consists of an optical filter, biprism and CCD camera. Since single CCD camera is used, this system has various advantages over the conventional stereo vision system using two cameras such as finding the corresponding points along the horizontal scanline. In this wort, the biprism stereo vision sensor was designed for the GMAW, and the linear calibration method was proposed to determine the prism and camera parameters. Image processing techniques were employed to find the corresponding point along the pool boundary. The ism-intensity contour corresponding to the pool boundary was found in the pixel order and the filter-based matching algorithm was used to refine the corresponding points in the subpixel order. Predicted bead dimensions were in broad agreements with the measured results under the conditions of spray mode and humping bead.

• Journal of KIISE:Software and Applications
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• v.34 no.1
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• pp.52-58
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• 2007

In this paper we propose a new robust method to extract accurate human silhouettes indoors with active stereo camera. A prime application is for gesture recognition of mobile robots. The segmentation of distant moving objects includes many problems such as low resolution, shadows, poor stereo matching information and instabilities of the object and background color distributions. There are many object segmentation methods based on color or stereo information but they alone are prone to failure. Here efficient color, stereo and image segmentation methods are fused to infer object and background areas of high confidence. Then the inferred areas are incorporated in graph cut to make human silhouette extraction robust and accurate. Some experimental results are presented with image sequences taken using pan-tilt stereo camera. Our proposed algorithms are evaluated with respect to ground truth data and proved to outperform some methods based on either color/stereo or color/contrast alone.

• Journal of the Korean Institute of Intelligent Systems
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• v.15 no.1
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• pp.42-47
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• 2005

In this papcr, we address the 3D reconstruction of the indoor circumstance using what the data is extracted by a pall of image from Stereo Camera. Generally sucaking, there arc three methods to extract 3-Dimensional data using IR sensor, Laser sensor and Stereo camera sensor. The best is stereo camera sensor which can show a high performance at a reasonable price. We used 'Window Correlation Matching Method' to extract 3-Dimensional data in stereo image. We proposed new Method to reduce error data, said 'Histogram Weighted Hough Transform'. Owing to this mettled, we reduced error data in each stereo image. So reconstruction is well done. 3-Dimensional Reconstruction is accomplished by using the DirectX that is well known as 3D-Game development tool. We show that the stereo camera can be not only used to extract 3-dimensional data but also applied to reconstruct the 3-Dimensional circumstance. And we try to reduce the error data using various method.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.6
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• pp.663-668
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• 2010

In this study a stereo digital camera system was developed. Using this system, we can collect informations such as coordinates, lengths of all objects shown in the photo image just by taking digital photograph in field. This system has the advantage of obtaining stereo images with settled exterior orientation parameters, while the accuracy slightly worsen because in a close range photogrammetry with stereo digital camera system, the base line distance is restricted within about 1m. We took images with various exposure distances and angles to objects for experimental error assessment, and analyzed the affection of image coordinates errors.

• Korean Journal of Remote Sensing
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• v.31 no.2
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• pp.171-182
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• 2015

We propose a camera system to acquire indoor stereo omni-directional images and its calibration method. These images can be utilized for indoor precise mapping and sophisticated imagebased services. The proposed system is configured with a rotating stereo line camera system, providing stereo omni-directional images appropriate to stable stereoscopy and precise derivation of object point coordinates. Based on the projection model, we derive a mathematical model for the system calibration. After performing the system calibration, we can estimate object points with an accuracy of less than ${\pm}16cm$ in indoor space. The proposed system and calibration method will be applied to indoor precise 3D modeling.