Huanzhang Lu

National University of Defense Technology, Ch’ang-sha-shih, Hunan, China

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Publications (4)4.63 Total impact

  • Xiongming Zhang · Lizhi Cheng · Huanzhang Lu
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    ABSTRACT: This paper presents a unified approach for low-memory and on-the-fly implementation of generic hierarchical transforms (GHTs) suited for parent–children tree (PCT) production, called the stripe-based hierarchical transform (SBHT). Here, the term “generic” means that totally different FBs may appear in different decomposition levels. This approach generates the exactly same subband coefficients as the traditional global implementation of GHTs with a low memory budget that is unrelated to the input signal length and only dependent on the GHT. The SBHT lends itself to the PCT-based image coding algorithm in the sense that the basic data unit generated by the SBHT is row-based collections of PCT structures, the most widely used data entity in subband coding. To demonstrate the SBHT's application in image coding, a PCT coder based on the LLEC is proposed to encode the PCTs generated by the SBHT. No intermediate buffering is needed between the SBHT and the codec. The experiments show that when the GHT is configured appropriately, the proposed coder provides competitive coding efficiency relative to the SPIHT and JPEG2000 with a very low memory budget and low computation complexity.
    No preview · Article · May 2009 · Signal Processing Image Communication
  • Xiongming Zhang · Lizhi Cheng · Huanzhang Lu · Deli Chen
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    ABSTRACT: We study the low-memory and on-the-fly implementation of generic tree-structured M-channel quadrature mirror filter (QMF) banks. A unified framework is proposed in which the forward and inverse transforms are addressed as an integral system. To cope with the decomposition of finite-length signals, an on-the-fly treatment of boundary extension is also presented. The proposed unified framework has the advantages of on-the-fly computation, memory requirement independent of the input signal length, adaptability to varied cascading patterns of filter banks (FBs), and most of all, producing exactly the same subband coefficients as those obtained by the conventional global transform that buffers the whole signal. Examples with 2-channel odd-length linear-phase finite impulse response (FIR) FBs as well as lapped transforms are presented to demonstrate the approach proposed. Lastly, a comparison of memory sizes for three typical configurations of tree-structured FBs is also provided to show the flexibility and application of this framework.
    No preview · Article · Nov 2008 · Signal Processing
  • Cong Zhang · Deli Chen · Huanzhang Lu · Huamin Tao
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    ABSTRACT: Many modulated communication signals exhibit a cyclostationarity property, corresponding to the underlying periodicity arising from carrier frequencies or baud rates. By exploiting cyclostationarity, the direction-of-arrival (DOA) estimation can be significantly improved. In this paper, we propose a new two-dimensional (2-D) DOA estimation method that exploits cyclostationarity to enhance the noise suppressing effect. The proposed method is based on the cyclic cross-correlations of sensor outputs and is asymptotically exact for both narrowband and wideband sources. In addition, the new method does not require any 2-D search or pair matching for 2-D DOA estimation problems. Theoretical analysis and computer simulation simultaneously indicate that the proposed method has a better performance in noise suppressing and signal selectivity.
    No preview · Conference Paper · Jul 2008
  • Yang Wang · Huanzhang Lu · Xiongming Zhang · Xu Han
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    ABSTRACT: We present a novel texture feature persistence metric for automatic-target-recognition (ATR)-directed image compression based on the similarity between shapes. On the basis of spatial fuzzy representation of shapes, a similarity metric between shapes is proposed. Then the impact of lossy image compression on ATR performance is measured by the similarity between shapes, which are obtained by identical segmentation and edge extraction of the source image and degraded image after compression. Experimental results show that this metric effectively measures the extent to which target texture features are preserved after compression. (c) 2006 Society of Photo-Optical Instrumentation Engineers.
    No preview · Article · Jun 2006 · Optical Engineering