15,347 research outputs found

    Visual assessment for the quantization error in wavelet based monochrome videos

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    The investigation of the discrete wavelet transform (DWT) based video coder is still undergoing in the literature. One of the open problems to be solved is the perception to the quantization noise in different subbands in the DWT domain. This is a critical issue for the development of a better motion compensation (MC) scheme. An experiment and relevant results analysis are presented in this paper to address the above issue. Monochrome video sequences of natural scenes are used in the experiment therefore the so-called masking effects can be taken into account in the decision of the sensitivity to the noise hidden in the DWT domain. The preliminary results show that the most sensitive subbands are those in the lowest three resolution levels under a five-levels decomposition scheme. The further analysis proves that the distribution of the sensitivity to each individual subband has been shifted by the context of the video

    Hybrid exciton-polaritons in a bad microcavity containing the organic and inorganic quantum wells

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    We study the hybrid exciton-polaritons in a bad microcavity containing the organic and inorganic quantum wells. The corresponding polariton states are given. The analytical solution and the numerical result of the stationary spectrum for the cavity field are finishedComment: 3 pages, 1 figure. appear in Communications in Theoretical Physic

    Bias-induced insulator-metal transition in organic electronics

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    We investigate the bias-induced insulator-metal transition in organic electronics devices, on the basis of the Su-Schrieffer-Heeger model combined with the non-equilibrium Green's function formalism. The insulator-metal transition is explained with the energy levels crossover that eliminates the Peierls phase and delocalizes the electron states near the threshold voltage. This may account for the experimental observations on the devices that exhibit intrinsic bistable conductance switching with large on-off ratio.Comment: 6 pages, 3 figures. To appear in Applied Physics Letter

    A wavelet interlaced video coding framework

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    A discrete wavelet transform (DWT) based codec with EBCOT/adaptive coding mode switching/low-band-shift (LBS) is presented in this paper. The adaptive coding mode switching is used for both intra- and inter-frame coding, respectively, to improve the rate vs. distortion (R-D) performance. EBCOT, the coding engine used in JPEG2000 is adopted in this framework because of its embedded R-D optimization capability which is most suitable for the application of a perceptual distortion measure (PDM). LBS is used for motion estimation (ME) in DWT domain, while context based MQ coding is adopted to code the motion vector (MV). The context design of MV coding is derived from H.264

    Acceleration and vacuum temperature

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    The quantum fluctuations of an "accelerated" vacuum state, that is vacuum fluctuations in the presence of a constant electromagnetic field, can be described by the temperature \TEH. Considering \TEH for the gyromagnetic factor g=1g=1 we show that \TEH(g=1)=\THU, where \THU is the Unruh temperature experienced by an accelerated observer. We conjecture that both particle production and nonlinear field effects inherent in the Unruh accelerated observer case are described by the case g=1g=1 QED of strong fields. We present rates of particle production for g=0,1,2g=0,1,2 and show that the case g=1g=1 is experimentally distinguishable from g=0,2g=0,2. Therefore, either accelerated observers are distinguishable from accelerated vacuum or there is unexpected modification of the theoretical framework.Comment: 4 pages, 1 figure; expanded discussion of experimental observables, added references, version appearing in Phys Rev
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