• IEIE Transactions on Smart Processing and Computing
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• v.3 no.6
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• pp.397-403
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• 2014

A new video compression standard called High Efficiency Video Coding (HEVC) has recently been released onto the market. HEVC provides higher coding performance compared to previous standards, but at the cost of a significant increase in encoding complexity, particularly in motion estimation (ME). At the same time, the computing capabilities of Graphics Processing Units (GPUs) have become more powerful. This paper proposes a parallel integer-pel ME (IME) algorithm for HEVC on GPU using the Compute Unified Device Architecture (CUDA). In the proposed IME, concurrent parallel reduction (CPR) is introduced. CPR performs several parallel reduction (PR) operations concurrently to solve two problems in conventional PR; low thread utilization and high thread synchronization latency. The proposed encoder reduces the portion of IME in the encoder to almost zero with a 2.3% increase in bitrate. In terms of IME, the proposed IME is up to 172.6 times faster than the IME in the HEVC reference model.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2012.07a
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• pp.457-458
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• 2012

본 논문에서는 저비트율 환경에서 화면내 예측 모드 정보를 적응적으로 부호화하는 방법을 제안한다. 저비트율 환경에서의 예측 모드의 확률정보에 기반하여 특성을 분석한 후 기존의 방법과 제안된 방법을 적응적으로 선택하여 예측 모드 정보를 부호화 한다. 제안된 방법에서는 기존의 MPM을 대체하여 하나의 MB내에서 MPM과 일치하지 않는 블록에 대한 개수에 대한 정보, 해당 블록의 위치 정보, 실제 모드 정보를 부호화하는 방법을 사용하였다. 실험 결과를 통해서, 제안된 기술은 저비트율 환경에서 평균적으로 0.10dB의 BD-PSNR 증가 또는 1.72%의 BD-bitrate를 감소시킴으로써 H264/AVC의 효율을 향상시킴을 확인할 수 있다.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.7 no.4
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• pp.205-211
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• 2014

This paper addresses the framework of object-oriented image coding, describing a new algorithm, based on monodimensional Legendre polynomials, for texture approximation. Through the use of 1D orthogonal basis functions, the computational complexity which usually makes prohibitive most of 2D region-oriented approaches is significantly reduced, while only a slight increment of distortion is introduced. In the aim of preserving the bidimensional intersample correlation of the texture information as much as possible, suitable pseudo-bidimensional basis functions have been used, yielding significant improvements with respect to the straightforward 1D approach. The algorithm has been experimented for coding still images as well as motion compensated sequences, showing interesting possibilities of application for very low bitrate video coding.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.44 no.4 s.316
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• pp.8-16
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• 2007

For the improvement of coding efficiency, the H.264/AVC video coding standard employs new coding tools compared with existing coding standards. However, due to these new coding tools, the complexity of K264/AVC standard encoder is greatly increased. Specifically, the inter/intra mode decision method using RDO(rate-distortion optimization) technique is one of the most complex parts in H.264/AVC. In this paper, we focus on the complexity reduction in macroblock mode decision. In the proposed method, we reduce the complexity of the $4{\times}4$ mode decision process using $4{\times}4$ simple square filters, and using spatial block correlation method. Additionally, exploiting the best mode of sub_macroblock in $Inter8{\times}8$ mode, we proposed an algorithm to eliminate some intra modes in current macroblock mode decision process. In addition, we employed a method to raise the probability to select SKIP, $Intra16{\times}16$, and $Intra16{\times}16$ modes which usually show low complexity and low bitrate compared with other modes. From the simulation results, the proposed algorithm reduce the encoding time by maximum 83% of total, and reduce the bitrate of the overall sequences by $8{\sim}10%$ on the average compared with existing coding methods.

• Journal of Broadcast Engineering
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• v.20 no.1
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• pp.40-47
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• 2015

This paper discusses QoS enhancement in the Best-effort services of the service plan provided by MPEG Media Transport (MMT) systems for video streaming applications. Among MMT services, i.e. per-flow, per-class, and best-effort services, the server does not provide guaranteed bandwidth for the best-effort service only. Therefore, in the best-effort services, a bandwidth access priority is defined for various services, where the lowest priority is assigned to the low-level video services. To alleviate the issue of bandwidth limitation in the best-effort services, this paper investigates transmission of low-resolution video with low bitrate and up-sampling. Our experimental results prove the superiority of the proposed method in terms of delivered video quality.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.10
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• pp.118-128
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• 2015

Compressive sensing (CS) has to face with two challenges of computational complexity reconstruction and low coding efficiency. As a solution, this paper presents a novel spatially scalable Kronecker two layer compressive sensing framework which facilitates reconstruction up to three spatial resolutions as well as much improved CS coding performance. We propose a dual-resolution sensing matrix based on the quincunx sampling grid which is applied to the base layer. This sensing matrix can provide a fast-preview of low resolution image at encoder side which is utilized for predictive coding. The enhancement layer is encoded as the residual measurement between the acquired measurement and predicted measurement data. The low resolution reconstruction is obtained from the base layer only while the high resolution image is jointly reconstructed using both two layers. Experimental results validate that the proposed scheme outperforms both conventional single layer and previous multi-resolution schemes especially at high bitrate like 2.0 bpp by 5.75dB and 5.05dB PSNR gain on average, respectively.

• Journal of the Korea Computer Industry Society
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• v.3 no.8
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• pp.1085-1092
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• 2002

Studies on image information processing have been performed since long time ago because in daily life most of information are acquired by the since of sight. Since there should be a lot of data to describe image as a digital form, data compression is required in order to store or transmit digital image. Lately among most of image compression methods adopted on image compression standards, transform coding methods have been primarily used which transforms the correlations between pixels of image on frequency domain before image compression. It is blown that the standard methods using especially DCT features blocking effect which is the major cause of degrading the quality of image at high compression rate. Fractal encoding using quadtree partition is applied after reducing original image, and we are to find a optimal encoding for the number of scaling bit and offset bit.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.170-173
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• 2009

In this paper, we propose a fast intra prediction mode selection method in Scalable Video Coding(SVC) which is an emerging video coding standard as an extension of H.264/Advanced Video Coding(H.264/AVC). The proposed method decides a candidate intra prediction mode based on the characteristic of macroblock smoothness. Statistical analysis is applied to computing that smoothness in spatial enhancement layer. We also propose an early termination scheme for Intra_BL mode decision where the RD cost value of Intra_BL is utilized. Compared with JSVM software, our scheme can reduce about 55% of the computation complexity of intra prediction on average, while the performance degradation is negligible; For low QP values, the average PSNR loss is very negligible, equivalently the bit rate increases by 0.01%. For high QP values, the average PSNR loss is less than 0.01dB, which equals to 0.25% increase in bitrate on average.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.43 no.4 s.310
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• pp.96-107
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• 2006

In this paper, a low bitrate video coding method based on new panoramic modeling is proposed for panning cameras. An input video frame from a panning camera is decomposed into a background image, rectangular moving object regions, and a residual image. In coding the background, we employ a panoramic model that can account for several image formation processes, such as perspective projection, lens distortion, vignetting and illumination effects. Moving objects aredetected, and their minimum bounding rectangular regions are coded with a JPEG-2000 coder. We have evaluated the effectiveness of the proposed algorithm with several indoor and outdoor sequences and found that the PSNR is improved by $1.3{\sim}4.4dB$ compared to that of JPEG-2000.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.241-242
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• 2006

MPEG Surround is an audio coding technology that represents multi-channel audio signal with downmixed audio signal(s) and very low bitrate side information based on Binaural Cue Coding. The side information consists of Inter-Channel Level Difference, Inter-Channel Correlation, and payloads. These two parameters are correspondent to the well-known spatial parameters in psycho-acoustics, Inter-aural Level Difference (ILD) and Inter-Aural Cross Correlation (IACC). Though ICLD is to provide perceptually equivalent ILD to the listener, however, the ILD of the original multi-channel audio signal and that of the MPEG Surround encoded signal was different. The difference between two ILD values is defined as ILD Distortion (ILDD). This paper provides how ILDD can be applied to enhance sound quality in MPEG Surround and how much ILDD is decreased.