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[Author] Huihui BAI(8hit)

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  • Compatible Stereo Video Coding with Adaptive Prediction Structure

    Lili MENG  Yao ZHAO  Anhong WANG  Jeng-Shyang PAN  Huihui BAI  

     
    LETTER-Image Processing and Video Processing

      Vol:
    E94-D No:7
      Page(s):
    1506-1509

    A stereo video coding scheme which is compatible with monoview-processor is presented in this paper. At the same time, this paper proposes an adaptive prediction structure which can make different prediction modes to be applied to different groups of picture (GOPs) according to temporal correlations and interview correlations to improve the coding efficiency. Moreover, the most advanced video coding standard H.264 is used conveniently for maximize the coding efficiency in this paper. Finally, the effectiveness of the proposed scheme is verified by extensive experimental results.

  • Fast CU Splitting in HEVC Intra Coding for Screen Content Coding

    Mengmeng ZHANG  Yang ZHANG  Huihui BAI  

     
    LETTER-Image Processing and Video Processing

      Vol:
    E98-D No:2
      Page(s):
    467-470

    The high efficiency video coding (HEVC) standard has significantly improved compression performance for many applications, including remote desktop and desktop sharing. Screen content video coding is widely used in applications with a high demand for real-time performance. HEVC usually introduces great computational complexity, which makes fast algorithms necessary to offset the limited computing power of HEVC encoders. In this study, a statistical analysis of several screen content sequences is first performed to better account for the completely different statistics of natural images and videos. Second, a fast coding unit (CU) splitting method is proposed, which aims to reduce HEVC intra coding computational complexity, especially in screen content coding. In the proposed scheme, CU size decision is made by checking the smoothness of the luminance values in every coding tree unit. Experiments demonstrate that in HEVC range extension standard, the proposed scheme can save an average of 29% computational complexity with 0.9% Bjøntegaard Delta rate (BD-rate) increase compared with HM13.0+RExt6.0 anchor for screen content sequences. For default HEVC, the proposed scheme can reduce encoding time by an average of 38% with negligible loss of coding efficiency.

  • Multiple Description Video Coding Using Inter- and Intra-Description Correlation at Macro Block Level

    Huihui BAI  Mengmeng ZHANG  Anhong WANG  Meiqin LIU  Yao ZHAO  

     
    LETTER-Image Processing and Video Processing

      Vol:
    E97-D No:2
      Page(s):
    384-387

    A novel standard-compliant multiple description (MD) video codec is proposed in this paper, which aims to achieve effective redundancy allocation using inter- and intra-description correlation. The inter-description correlation at macro block (MB) level is applied to produce side information of different modes which is helpful for better side decoding quality. Furthermore, the intra-description correlation at MB level is exploited to design the adaptive skip mode for higher compression efficiency. The experimental results exhibit a better rate of side and central distortion performance compared with other relevant MDC schemes.

  • A Novel Fast Intra Prediction Scheme for Depth-Map in 3D High Efficiency Video Coding

    Mengmeng ZHANG  Shenghui QIU  Huihui BAI  

     
    LETTER-Coding Theory

      Vol:
    E97-A No:7
      Page(s):
    1635-1639

    The development of 3D High Efficiency Video Coding (3D-HEVC) has resulted in a growing interest in the compression of depth-maps. To achieve better intra prediction performance, the Depth Modeling Mode (DMM) technique is employed as an intra prediction technique for depth-maps. However, the complexity and computation load have dramatically increased with the application of DMM. Therefore, in view of the limited colors in depth-maps, this paper presents a novel fast intra coding scheme based on Base Colors and Index Map (BCIM) to reduce the complexity of DMM effectively. Furthermore, the index map is remapped, and the Base Colors are coded by predictive coding in BCIM to improve compression efficiency. Compared with the intra prediction coding in DMM, the experimental results illustrate that the proposed scheme provides a decrease of approximately 51.2% in the intra prediction time. Meanwhile, the BD-rate increase is only 0.83% for the virtual intermediate views generated by Depth-Image-Based Rendering.

  • Just Noticeable Difference Based Fast Coding Unit Partition in HEVC Intra Coding

    Meng ZHANG  Huihui BAI  Meiqin LIU  Anhong WANG  Mengmeng ZHANG  Yao ZHAO  

     
    LETTER-Image

      Vol:
    E97-A No:12
      Page(s):
    2680-2683

    As an ongoing video compression standard, High Efficiency Video Coding (HEVC) has achieved better rate distortion performance than H.264, but it also leads to enormous encoding complexity. In this paper, we propose a novel fast coding unit partition algorithm in the intra prediction of HEVC. Firstly, instead of the time-consuming rate distortion optimization for coding mode decision, just-noticeable-difference (JND) values can be exploited to partition the coding unit according to human visual system characteristics. Furthermore, coding bits in HEVC can also be considered as assisted information to refine the partition results. Compared with HEVC test model HM10.1, the experimental results show that the fast intra mode decision algorithm provides over 28% encoding time saving on average with comparable rate distortion performance.

  • Edge-Based Adaptive Sampling for Image Block Compressive Sensing

    Lijing MA  Huihui BAI  Mengmeng ZHANG  Yao ZHAO  

     
    LETTER-Image

      Vol:
    E99-A No:11
      Page(s):
    2095-2098

    In this paper, a novel scheme of the adaptive sampling of block compressive sensing is proposed for natural images. In view of the contents of images, the edge proportion in a block can be used to represent its sparsity. Furthermore, according to the edge proportion, the adaptive sampling rate can be adaptively allocated for better compressive sensing recovery. Given that there are too many blocks in an image, it may lead to a overhead cost for recording the ratio of measurement of each block. Therefore, K-means method is applied to classify the blocks into clusters and for each cluster a kind of ratio of measurement can be allocated. In addition, we design an iterative termination condition to reduce time-consuming in the iteration of compressive sensing recovery. The experimental results show that compared with the corresponding methods, the proposed scheme can acquire a better reconstructed image at the same sampling rate.

  • Fast Intra Coding Algorithm for HEVC Based on Decision Tree

    Jia QIN  Huihui BAI  Mengmeng ZHANG  Yao ZHAO  

     
    LETTER-Image

      Vol:
    E100-A No:5
      Page(s):
    1274-1278

    High Efficiency Video Coding (HEVC) is the latest coding standard. Compared with Advanced Video coding (H.264/AVC), HEVC offers about a 50% bitrate reduction at the same reconstructed video quality. However, this new coding standard leads to enormous computational complexity, which makes it difficult to encode video in real time. Therefore, in this paper, aiming at the high complexity of intra coding in HEVC, a new fast coding unit (CU) splitting algorithm is proposed based on the decision tree. Decision tree, as a method of machine learning, can be designed to determine the size of CUs adaptively. Here, two significant features, Just Noticeable Difference (JND) values and coding bits of each CU can be extracted to train the decision tree, according to their relationships with the CUs' partitions. The experimental results have revealed that the proposed algorithm can save about 34% of time, on average, with only a small increase of BD-rate under the “All_Intra” setting, compared with the HEVC reference software.

  • Standard-Compliant Multiple Description Image Coding Based on Convolutional Neural Networks

    Ting ZHANG  Huihui BAI  Mengmeng ZHANG  Yao ZHAO  

     
    LETTER-Image Processing and Video Processing

      Pubricized:
    2018/07/19
      Vol:
    E101-D No:10
      Page(s):
    2543-2546

    Multiple description (MD) coding is an attractive framework for robust information transmission over non-prioritized and unpredictable networks. In this paper, a novel MD image coding scheme is proposed based on convolutional neural networks (CNNs), which aims to improve the reconstructed quality of side and central decoders. For this purpose initially, a given image is encoded into two independent descriptions by sub-sampling. Such a design can make the proposed method compatible with the existing image coding standards. At the decoder, in order to achieve high-quality of side and central image reconstruction, three CNNs, including two side decoder sub-networks and one central decoder sub-network, are adopted into an end-to-end reconstruction framework. Experimental results show the improvement achieved by the proposed scheme in terms of both peak signal-to-noise ratio values and subjective quality. The proposed method demonstrates better rate central and side distortion performance.