• Journal of Broadcast Engineering
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• v.11 no.2 s.31
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• pp.222-228
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• 2006

In this paper, we propose a receive diversity method for orthogonal frequency division multiplexing (OFDM) systems with cochannel interference. In the method, combining is done in the frequency domain by using the subcarrier based maximum ratio combining (MRC) method. For MRC, we exploit the power of cochannel interference as well as the power of channel noise. The accuracy of the power estimate of interference plus noise is enhanced by averaging the initial estimates over the correlated subchannels where the coherency between the subchannel gains comes from the limited delay spread of the channel. Simulation results show that the proposed method yields 2-3.5dB gain of signal to noise ratio compared to the conventional MRC method and less than 1 dB difference to the ideal case.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.6
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• pp.55-61
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• 2013

In this paper, we describe design and implementation of audio encoder/decoder for voice synthesis. It uses the encoding of difference value of successive samples instead of the original sample value. and has the compression ratio of 4. The function is verified by using FPGA and the performance is measured by the fabricated chip using $0.35{\mu}m$ standard CMOS process. The system clock is 16.384MHz. The measured THD+n is from -40dB to -80dB with frequency variation and the power consumption is about 80mW. It is suited for the mobile application of high audio quality and low power consumption.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.2
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• pp.267-272
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• 2017

In this paper, we suggested that a RF-front module of down-converter that represents the lowest noise figure to receive high quality video signals because the attenuation occurs in the atmosphere over 20GHz. By budget analysis of CDR, SFDR and CIP3 of RF-FEM, we also analyzed the parameters and linearity that presents high dynamic range. The total gain of designed Ka-band down-converter is 61.8dBand noise figure is 1.05dB, so gain and noise figures show excellent properties. In the future, the designed RF-FEM will be applied to the Ka-band satellite down-converter for UHD-class video transmission.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2020.07a
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• pp.576-578
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• 2020

최근 사용자에게 더욱 몰입감 있는 콘텐츠를 제공하기 위한 기술에 대한 관심이 증가하고 있으며 기존의 2D 콘텐츠와는 다른 새로운 방식인 3D 콘텐츠에 대한 연구가 활발히 진행되고 있으며 그 중 가장 대표적인 것이 Point Cloud 영상이라고 할 수 있다. Point Cloud의 경우 수많은 3차원 좌표를 가진 점들로 구성되어 있으며 각 점들마다 Attribute 값을 이용하여 색상 등의 표현이 가능한 구조로 이루어져 있다. 이러한 특성 때문에 Point Cloud 데이터는 방대한 용량을 가지고 있으며 기존의 2D 방식과 데이터 구조가 상이하기 때문에 새로운 압축 표준이 요구되었다. 이에 미디어 표준화 단체인 MPEG(Moving Picture Experts Group)에서는 MPEG-I(Immersive) 차세대 프로젝트 그룹을 이용하여 이러한 움직임에 대응하고 있다. MPEG-I의 part 5(Video-based Point Cloud Compression, V-PCC)에서는 객체를 대상으로 하여 기존의 비디오 코덱을 활용한 Point Cloud 압축 표준화를 진행중이다. V-PCC 데이터의 경우 기존의 2D 영상 데이터와 같이 전송을 통해 소비될 가능성이 아주 높기 때문에 이에 대한 고려가 필요하다. 현재 MPEG에서 표준화를 완료한 MMT(MPEG Media Transport)라는 전송 표준이 존재하기 때문에 이 기술을 활용 가능할 것으로 보인다. 따라서 본 논문에서는 Point Cloud 데이터를 압축한 V-PCC 데이터를 전송 표준 방식인 MMT를 이용하여 전송하는 방안에 대하여 제안한다.

• Journal of Broadcast Engineering
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• v.16 no.2
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• pp.305-318
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• 2011

Since switched digital video (SDV) provides specific programs only to the subscribers who request the programs, SDV has attracted considerable interest of MSOs for bandwidth efficiency. In North America, MSOs service over 2.3 million households with the SDV for cable networks. In Korea, since demand of HD program, high-speed Internet, VoD, and VoIP is noticeably rising, the SDV is considered as the alternative for bandwidth saving and efficient managing. In this paper, the characteristics, operating structure, and bandwidth saving of the SDV are discussed and technical requirements for the SDV are also introduced. The channel switching performance and stability of the SDV are analyzed through the test-bed.

• Journal of Broadcast Engineering
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• v.11 no.2 s.31
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• pp.164-173
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• 2006

The data structure of the concentric mosaic can be regarded as a video sequence with a slowly panning camera. We take a concentric mosaic with match or alignment of video sequences. Also the concentric mosaic required for huge memory. Thus, compressing is essential in order to use the concentric mosaic. Therefore we need the algorithm that compressed data structure was maintained and the scene was decoded. In this paper, we used 3D lifting transform to compress concentric mosaic. Lifting transform has a merit of wavelet transform and reduces computation quantities and memory. Because each frame has high correlation, the complexity which a scene is detected form 3D transformed bitstream is increased. Thus, in order to have higher performance and decrease the complexity of detecting of a scene we executed 3D lifting and then transformed data set was sequently compressed with each frame unit. Each frame has a flexible bit rate. Also, we proposed the algorithm that compressed data structure was maintained and the scene was decoded by using property of lifting structure.

• Journal of Broadcast Engineering
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• v.27 no.5
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• pp.638-653
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• 2022

In this paper, we propose the new method of creating 3D virtual-human reflecting the pattern of clothes worn by the person in the high-resolution whole body front image and the body shape data about the person. To get the pattern of clothes, we proceed Instance Segmentation and clothes parsing using Cascade Mask R-CNN. After, we use Pix2Pix to blur the boundaries and estimate the background color and can get UV-Map of 3D clothes mesh proceeding UV-Map base warping. Also, we get the body shape data using SMPL-X and deform the original clothes and body mesh. With UV-Map of clothes and deformed clothes and body mesh, user finally can see the animation of 3D virtual-human reflecting user's appearance by rendering with the state-of-the game engine, i.e. Unreal Engine.

• International Journal of Internet, Broadcasting and Communication
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• v.15 no.4
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• pp.178-184
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• 2023

AI image generation technology has become a popular research direction in the field of AI, which is widely used in the field of digital art and conceptual design, and can also be used in the process of 3D texture mapping. This paper introduces the production process of 3D texture mapping using AI image technology, and discusses whether it can be used as a new way of 3D texture mapping to enrich the 3D texture mapping production process. Two AI deep learning models, Stable Diffusion and Midjourney, were combined to generate high-quality AI textures. Finally, the lmage to material function of substance 3D Sampler was used to convert the AI-generated textures into PBR 3D texture maps. And applied in 3D environment. This study shows that 3D texture maps generated by AI image generation technology can be used in 3D environment, which not only has short production time and high production efficiency, but also has rich changes in map styles, which can be quickly adjusted and modified according to the design scheme. However, some AI texture maps need to be manually modified before they can be used. With the continuous development of AI technology, there will be great potential for further development and innovation of AI-generated image technology in the 3D content production process in the future.

• International journal of advanced smart convergence
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• v.12 no.4
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• pp.293-299
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• 2023

In recent years, with the rapid development of real-time rendering technology, the quality of the images produced by real-time rendering has been improving, and its application scope has been expanded from games to animation and advertising and other fields. This paper analyses the development status of real-time rendering technology in 3D animation by investigating the 3D animation market in China, which concludes that the number of 3D animations in China has been increasing over the past 20 years, and the number of 3D animations using real-time rendering has been increasing year by year and exceeds that of 3D animations using offline rendering. In this study, a real-time rendering and offline rendering 3D animation are selected respectively to observe the screen effect of characters, special effects and environment props, and analyse the advantages and disadvantages of the two rendering technologies, and finally conclude that there is not much difference between real-time rendering 3D animation and offline rendering 3D animation in terms of quality and the overall sense of view, and due to the real-time rendering of the characteristics of the WYSIWYG, the animation designers can better focus on the creation of art performance. Real-time rendering technology has a good development prospect and potential in 3D animation, which paves the way for designers to create 3D content more efficiently.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2020.07a
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• pp.500-504
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• 2020

포인트 클라우드는 수십만 또는 수백만개의 포인트로 객체 또는 장면을 나타내며, 그 데이터의 양은 엄청 나기 때문에, 다양한 대역폭 또는 장치에서 효과적인 서비스를 위해 확장성 기능을 갖춘 압축 체계 개발이 필요하다. 이에 따라, 단방향 패치 패킹을 활용한 LoD 제어 테이블 기반 밀도 확장성(LoD control table based Density scalability by using Unidirectional Patch packing, LDUP) 방법을 이용한 확장성에 대한 연구가 이루어졌다. 그러나, LDUP 방법은 2D 그리드의 크기를 조작하는데 한계가 있어, 패치 사이의 거리가 드물게 패킹되고, 이는 압축 효율을 떨어뜨린다. 본 논문에서는 이러한 단점을 극복하기 위해 양방향 패치 패킹을 활용한 LoD 제어 테이블 기반 밀도 확장성(LoD control table based Density scalability by using Bidirectional Patch packing, LDBP) 방식을 제안한다. 제안된 LDBP 방법은 패치가 패킹된 영상에서 빈 공간을 효과적으로 감소시켰으며, 압축 효율 측면에서 LDUP 방법에 비해 더 높은 BD-Rate 이점을 얻었다. 제안된 LDBP 방법은 3D 포인트 클라우드 압축 시 포인트 클라우드 밀도 확장성을 기존의 LDUP 보다 효과적으로 달성하였다.