• The Journal of Korea Robotics Society
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• v.12 no.1
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• pp.33-41
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• 2017

We present a region-based approach for accurate pose estimation of small mechanical components. Our algorithm consists of two key phases: Multi-view object co-segmentation and pose estimation. In the first phase, we explain an automatic method to extract binary masks of a target object captured from multiple viewpoints. For initialization, we assume the target object is bounded by the convex volume of interest defined by a few user inputs. The co-segmented target object shares the same geometric representation in space, and has distinctive color models from those of the backgrounds. In the second phase, we retrieve a 3D model instance with correct upright orientation, and estimate a relative pose of the object observed from images. Our energy function, combining region and boundary terms for the proposed measures, maximizes the overlapping regions and boundaries between the multi-view co-segmentations and projected masks of the reference model. Based on high-quality co-segmentations consistent across all different viewpoints, our final results are accurate model indices and pose parameters of the extracted object. We demonstrate the effectiveness of the proposed method using various examples.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.6
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• pp.127-136
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• 2010

In multi-view video, illumination disharmony between neighboring views can occur on account of different location of each camera and imperfect camera calibration, and so on. Such discrepancy can be the cause of the performance decrease of multi-view video coding by mismatch of inter-view prediction which refer to the pictures obtained from the neighboring views at the same time. In this paper, we propose an efficient histogram-based prefiltering algorithm to compensate mismatches between the luminance and chrominance components in multi-view video for improving its coding efficiency. To compensate illumination variation efficiently, all camera frames of a multi-view sequence are adjusted to a predefined reference through the histogram matching. A Cosited filter that is used for chroma subsampling in many video encoding schemes is applied to each color component prior to histogram matching to improve its performance. The histogram matching is carried out in the RGB color space after color space converting from YCbCr color space. The effective color conversion skill that has respect to direction of edge and range of pixel value in an image is employed in the process. Experimental results show that the compression ratio for the proposed algorithm is improved comparing with other methods.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.505-508
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• 2009

The super multi-view (SMV) display and the high-density directional (HDD) display were proposed as a natural 3D display that is free from the visual fatigue caused by the accommodation-vergence conflict and provides smooth motion parallax. The multi-projection system, the flat-panel system, and the time-multiplexing system are used to construct the HDD displays. The recent progress of the HDD 3D display is reviewed.

• Journal of KIISE
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• v.41 no.11
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• pp.900-910
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• 2014

Multi-view video is obtained by capturing one three-dimensional scene with many cameras at different positions. The computational complexity of multi view video coding increases in proportion to the number of cameras. To reduce computational complexity and maintain the image quality, improved prediction structure and motion estimation method is proposed in this paper. The proposed prediction structure exploits an average distance between the current picture and its reference pictures. The proposed prediction structure divides every GOP into several groups to decide the maximum index of hierarchical B layer and the number of pictures of each B layer. And the proposed motion estimation method uses a hierarchical search strategy. This strategy method consists of modified diamond search pattern, progressive diamond search pattern and modified raster search pattern. Experiment results show that the complexity reduction of the proposed prediction structure and motion estimation method over JMVC (Joint Multiview Video Coding) reference model using hierarchical B pictures of Fraunhofer-HHI and TZ search method can be up to 40~70% while maintaining similar video quality and bit rates.

• Journal of Broadcast Engineering
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• v.11 no.4 s.33
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• pp.458-470
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• 2006

This paper describes issues and consideration on authoring of interactive multi-view visual content based on MPEG-4. The issues include types of multi-view visual content; scene composition for rendering; functionalities for user-interaction; and multi-view visual content file format. The MPEG-4 standard, which aims to provide an object based audiovisual coding tool, has been developed to address the emerging needs from communications, interactive broadcasting as well as from mixed service models resulting from technological convergence. Due to the feature of object based coding, the use of MPEG-4 can resolve the format diversity problem of multi-view visual contents while providing high interactivity to users. Throughout this paper, we will present which issues need to be determined and how they can be realized by means of MPEG-4 Systems.

• Journal of Korea Multimedia Society
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• v.23 no.2
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• pp.166-173
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• 2020

Multi-view images, which are widely used for providing free-viewpoint services, can enhance the quality of synthetic views when the number of views increases. However, there needs an efficient representation method because of the tremendous amount of data. In this paper, we propose a method for generating point cloud data for the efficient representation of multi-view color and depth images. The proposed method conducts sequential reconstruction of point clouds at each viewpoint as a method of deleting duplicate data. A 3D point of a point cloud is projected to a frame to be reconstructed, and the color and depth of the 3D point is compared with the pixel where it is projected. When the 3D point and the pixel are similar enough, then the pixel is not used for generating a 3D point. In this way, we can reduce the number of reconstructed 3D points. Experimental results show that the propose method generates a point cloud which can generate multi-view images while minimizing the number of 3D points.

• Journal of Broadcast Engineering
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• v.25 no.5
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• pp.798-807
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• 2020

As technologies using digital camera have been developed, 3D images can be constructed from the pictures captured by using multiple cameras. The 3D image data is represented in a form of point cloud which consists of 3D coordinate of the data and the related attributes. Various techniques have been proposed to construct the point cloud data. Among them, Structure-from-Motion (SfM) and Multi-view Stereo (MVS) are examples of the image-based technologies in this field. Based on the conventional research, the point cloud data generated from SfM and MVS may be sparse because the depth information may be incorrect and some data have been removed. In this paper, we propose an efficient algorithm to enhance the point cloud so that the density of the generated point cloud increases. Simulation results show that the proposed algorithm outperforms the conventional algorithms objectively and subjectively.

• Journal of Broadcast Engineering
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• v.11 no.4 s.33
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• pp.507-520
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• 2006

In this paper, we propose an application of OpenGL functions for novel view synthesis from multi-view images and depth maps. While image based rendering has been meant to generate synthetic images by processing the camera view with a graphic engine, little has been known about how to apply the given images and depth information to the graphic engine and render the scene. This paper presents an efficient way of constructing a 3D space with camera parameters, reconstructing the 3D scene with color and depth images, and synthesizing virtual views in real-time as well as their depth images.

• KIEAE Journal
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• v.9 no.6
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• pp.57-64
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• 2009

To make a prediction for a change of residential environment caused by the building code in Seoul which includes loosening the distance between multi-residential buildings, proposals of the four main building arrangements by analyzing examples were selected and then, amount of daylight and view efficiency were analyzed and presented through computer simulation for the proposals. In the result of the analysis, there was a difference among the arrangements but, when the distance between buildings was applied 0.8H as the least, residential environment like daylight and view efficiency per unit significantly decreased in quality. Particularly, for the middle stories(6-15) and the high stories(16~24), when the distance between buildings decreased from the current measurement, 1.0H, to 0.8H, the analysis indicated that 28% of daylight and 7% of view efficiency were reduced. In the building arrangements, an order of the best residential environment was followed in this sequence; balanced arrangement of flat type as the best, combined arrangement between L-shape and tower types, balanced arrangement of tower type, combined arrangement between flat and Y-shape types, grid arrangement of flat type, and combined arrangement between Y-shape and tower types as the least.

• Journal of KIISE:Computing Practices and Letters
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• v.13 no.4
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• pp.205-212
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• 2007

In this paper, we present a prototype of view-switchable high-definition (HD) multi-view video transmission system. One of the major bottlenecks for the multi-view broadcasting system has been the hardware cost and transmission bandwidth. The proposed system focuses on software-based design, transmission over IP multicast networks, and flexible system configuration to address aforementioned problems. In the proposed system, we implement software stereo HD multiplexing, demultipiexing and decoding, and take advantage of high-speed broadband convergence networks to deliver HD video in real-time. Moreover, the proposed system can be scalable and flexible in terms of the number of views. Furthermore, in order to display any multiview video on 3D display monitor, a face tracking system is integrated to our system. Therefore, users can watch the different stereoscopic video at its related locations.