• Journal of Broadcast Engineering
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• v.26 no.6
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• pp.692-703
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• 2021

Recently, with the development of computer graphics technology, research on technology for expressing real objects as more realistic virtual graphics is being actively conducted. Point cloud is a technology that uses numerous points, including 2D spatial coordinates and color information, to represent 3D objects, and they require huge data storage and high-performance computing devices to provide various services. Video-based Point Cloud Compression (V-PCC) technology is currently being studied by the international standard organization MPEG, which is a projection based method that projects point cloud into 2D plane, and then compresses them using 2D video codecs. V-PCC technology compresses point cloud objects using 2D images such as Occupancy map, Geometry image, Attribute image, and other auxiliary information that includes the relationship between 2D plane and 3D space. When increasing the density of point cloud or expanding an object, 3D calculation is generally used, but there are limitations in that the calculation method is complicated, requires a lot of time, and it is difficult to determine the correct location of a new point. This paper proposes a method to generate additional points at more accurate locations with less computation by applying 2D interpolation to the image on which the point cloud is projected, in the V-PCC technology.

• Journal of Electrical Engineering and Technology
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• v.9 no.5
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• pp.1762-1773
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• 2014

In this paper, a distributed image coding scheme for multi-view video through an efficient generation of side information is proposed. A distributed video coding technique corrects the errors in the side information, which is generated with the original image, by using the channel coding technique at the decoder. Therefore, the more correct the generated side information is, the better the performance of distributed video coding. The proposed technique is to apply the distributed video coding schemes to the image coding for multi-view video. It generates side information by selectively and efficiently using both 3-dimensional warping based on the depth map with spatially adjacent frames and motion-compensated temporal interpolation with temporally adjacent frames. In this scheme the difference between the adjacent frames, the sizes of the motion vectors for the adjacent blocks, and the edge information are used as the selection criteria. From the experiments, it was observed that the quality of the side information generated by the proposed technique was improved by the average peak signal-to-noise ratio of 0.97dB than the one by motion-compensated temporal interpolation or 3-dimensional warping. The result from analyzing the rate-distortion curves revealed that the proposed scheme could reduce the bit-rate by 8.01% on average at the same peak signal-to-noise ratio value, compared to previous work.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.1
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• pp.242-259
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• 2015

Three-dimensional video coding is one of the main challenges restricting the widespread applications of 3D video and free viewpoint video. In this paper, a novel fractal coding algorithm with motion-vector-field-based motion estimation for depth map sequence is proposed. We firstly add pre-search restriction to rule the improper domain blocks out of the matching search process so that the number of blocks involved in the search process can be restricted to a smaller size. Some improvements for motion estimation including initial search point prediction, threshold transition condition and early termination condition are made based on the feature of fractal coding. The motion-vector-field-based adaptive hexagon search algorithm on the basis of center-biased distribution characteristics of depth motion vector is proposed to accelerate the search. Experimental results show that the proposed algorithm can reach optimum levels of quality and save the coding time. The PSNR of synthesized view is increased by 0.56 dB with 36.97% bit rate decrease on average compared with H.264 Full Search. And the depth encoding time is saved by up to 66.47%. Moreover, the proposed fractal depth map sequence codec outperforms the recent alternative codecs by improving the H.264/AVC, especially in much bitrate saving and encoding time reduction.

• Journal of Broadcast Engineering
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• v.16 no.2
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• pp.258-273
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• 2011

This paper designs and implements a multi-view 3D video player system which is operated faster than existing video player systems. The structure for obtaining the near optimum speed in a multi-processor environment by parallelizing the component modules is proposed to process large volumes of multi-view image data at high speed. In order to use the concurrency of bottleneck, we designed image decoding, synthesis and rendering modules in a pipeline structure. For load balancing, the decoder module is divided into the unit of viewpoint, and the image synthesis module is geometrically divided based on synthesized images. As a result of this experiment, multi-view images were correctly synthesized and the 3D sense could be felt when watching the images on the multi-view autostereoscopic display. The proposed application processing structure could be used to process large volumes of multi-view image data at high speed, using the multi-processors to their maximum capacity.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.8C
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• pp.782-789
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• 2009

In this paper, we propose an algorithm for creating stereoscopic video from a monoscopic video. Parallel straight lines in a 3D space get narrower as they are farther from the perspective images on a 2D plane and finally meet at one point that is called a vanishing point. A viewer uses depth perception clues called a vanishing point which is the farthest from a viewer's viewpoint in order to perceive depth information from objects and surroundings thereof to the viewer. The viewer estimates the vanishing point with geometrical features in monoscopic images, and can perceive the depth information with the relationship between the position of the vanishing point and the viewer's viewpoint. In this paper, we propose a method to estimate a vanishing point with edge direction histogram in a general monoscopic image and to create a depth map depending on the position of the vanishing point. With the conversion method proposed through the experimental results, it is seen that stable stereoscopic conversion of a given monoscopic video is achieved.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.4
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• pp.105-113
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• 2010

In this paper, a 1.485 Gbps video signal transmission system using the carrier frequency of 240 GHz band was designed and simulated. The sub-harmonic mixer based on Schottky barrier diode was simulated in the transmitter and receiver. Both of heterodyne and direct detection receivers were simulated for each performance analysis. The ASK modulation was used in the transmitter and the envelop detection method was used in the receiver. The transmitter simulation results showed that the RF output power was -11.4 dBm($73{\mu}W$), when the IF input power was -3 dBm(0.5 mW) at the LO power of 7 dBm(5 mW) in sub-harmonic mixer, which corresponds to SSB(Single Side Band) conversion loss of 8.4 dB. This value is similar to the conversion loss of 8.0 dB(SSB) of VDI's commercial model WR3.4SHM(220~325 GHz) at 240 GHz. The combined transmitter and receiver simulation results showed that the recovered signal waveforms were in good agreement to the transmitted 1.485 Gbps NRZ signal.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.57-60
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• 2008

In this paper, we describe the technology about multiview video coding which is a hot issue in diqital video coding. A multiview video coding (MVC) is able to provide a free view point and 3-D effect, resulting that it gives more realism to users. Now, the MVC has been standardized as an amendment of H.264/AVC. In this paper, we present not only the MVC standard but also relevant techniques which were under consideration in the MVC standardization.

• Journal of the Korea Computer Graphics Society
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• v.18 no.1
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• pp.1-9
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• 2012

Video-based modeling / rendering developed to produce photo-realistic video contents have been one of the important research topics in computer graphics and computer visions. To smoothly combine original input video clips and 3D graphic models, geometrical information of light sources and cameras used to capture a scene in the real world is essentially required. In this paper, we present a simple technique to estimate the position and orientation of an optimal light source from the topology of objects and the silhouettes of shadows appeared in the original video clips. The technique supports functions to generate well matched shadows as well as to render the inserted models by applying the estimated light sources. Shadows are known as an important visual cue that empirically indicates the relative location of objects in the 3D space. Thus our method can enhance realism in the final composed videos through the proposed shadow generation and rendering algorithms in real-time.

• Journal of Broadcast Engineering
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• v.20 no.3
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• pp.368-378
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• 2015

3D conversion technology has been studied over past decades and integrated to commercial 3D displays and 3DTVs. The 3D conversion plays an important role in the augmented functionality of three-dimensional television (3DTV), because it can easily provide 3D contents. Generally, depth cues extracted from a static image is used for generating a depth map followed by DIBR (Depth Image Based Rendering) rendering for producing a stereoscopic image. However except some particular images, the existence of depth cues is rare so that the consistent quality of a depth map cannot be accordingly guaranteed. Therefore, it is imperative to make a 3D conversion method that produces satisfactory and consistent 3D for diverse video contents. From this viewpoint, this paper proposes a novel method with applicability to general types of image. For this, saliency as well as edge is utilized. To generate a depth map, geometric perspective, affinity model and binomic filter are used. In the experiments, the proposed method was performed on 24 video clips with a variety of contents. From a subjective test for 3D perception and visual fatigue, satisfactory and comfortable viewing of 3D contents was validated.

• Journal of the Korea Society of Computer and Information
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• v.27 no.10
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• pp.95-103
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• 2022

As 5G mobile communication services gradually expand in P2P (peer-to-peer) or D2D (device-to-device) applications, traffic-oriented stream control such as YouTube streaming is emerging as an important technology. In D2D communication, the type of data stream most frequently transmitted by users is a video stream, which has the characteristics of a large-capacity transport stream. In a D2D communication environment, this type of stream not only provides a cause of traffic congestion, but also degrades the quality of service between D2D User Equipments (DUEs). In this paper, we propose a Traffic-Oriented Stream Scheduling (TOSS) scheme to minimize the interruption of dynamic media streams such as video streams and to optimize streaming service quality. The proposed scheme schedules the media stream by analyzing the characteristics of the media stream and the traffic type in the bandwidth of 3.5 GHz and 28 GHz under the 5G gNB environment. We examine the performance of the proposed scheme through simulation, and the simulation results show that the proposed scheme has better performance than other comparative methods.