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IEE Proceedings I - Communications, Speech and Vision

Issue 5 • Oct. 1991

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Displaying Results 1 - 18 of 18
  • Removal of subjective redundancy from DCT-coded images

    Publication Year: 1991, Page(s):345 - 350
    Cited by:  Papers (16)  |  Patents (6)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (659 KB)

    The removal of subjective redundancy from video images has recently become an important area of study. A suggested method of removing this redundancy from transform-coded images is through the psychovisual thresholding and quantisation of the image transform coefficients. In this paper, the coefficient thresholding and quantisation levels are based on the combined effects of spatial masking and th... View full abstract»

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  • Motion detection and estimation of multiple moving objects in an image sequence using the cosine area transform (CAT)

    Publication Year: 1991, Page(s):351 - 356
    Cited by:  Papers (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (494 KB)

    A new technique for estimating the velocities of moving objects is presented. This technique is based on applying the cosine area transform (CAT) to the image sequence. The analysis of the CAT domain indicates that the velocities of the moving objects are related to the locations of the peaks in the CAT spectrum. The method of applying the CAT to an image sequence of multiple moving objects is pre... View full abstract»

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  • Fast algorithm for VQ codebook design

    Publication Year: 1991, Page(s):357 - 362
    Cited by:  Papers (10)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (486 KB)

    The paper presents a fast codebook training algorithm for vector quantisation. It uses an elimination rule, based on triangular inequality criteria, as well as the partial distortion elimination method, to relieve the computational burden of a conventional codebook training algorithm, including a binary codeword splitting algorithm for the initial codebook and the LBG recursive algorithm. Over 95%... View full abstract»

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  • Comparing coding efficiency of vector chain coding and run-length coding for line drawings

    Publication Year: 1991, Page(s):363 - 370
    Cited by:  Papers (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (649 KB)

    More efficient data compression can be achieved in encoding line drawings by vector chain coding (VCC) than by the traditional run-length coding (RLC), provided the total length of the lines within a line drawing is not excessive. More bandwidth or time can thus be saved in transmitting such pictures by using VCC. Although this has so far been established only intuitively, quantitative analysis an... View full abstract»

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  • Border marriage: matching of contours of serial sections

    Publication Year: 1991, Page(s):371 - 376
    Cited by:  Papers (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (523 KB)

    Surface triangulation methods are often used to reconstruct biomedical objects from serial tomographs. The contours extracted from such images must be matched prior to surface tiling. Previously, researchers used relatively simple objects with trivial matching conditions, or used a priori knowledge, or matched the contours manually. This paper describes a new method for matching contours based on ... View full abstract»

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  • Karhunen-Loeve method for data compression and speech synthesis

    Publication Year: 1991, Page(s):377 - 380
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (336 KB)

    The use of the Karhunen-Loeve (KL) method in speech data compression and synthesis using the Fourier-Bessel (FB) expansion coefficients of speech signals is described. Bessel functions seem to make a natural basis for speech signal decomposition. Sinusoidal functions are the eigenfunctions of vibrating strings. Bessel functions are the eigenfunctions of vibrating pipes. The vocal tract resembles a... View full abstract»

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  • Combination of block-coded modulation and trellis-coded modulation

    Publication Year: 1991, Page(s):381 - 386
    Cited by:  Papers (3)  |  Patents (3)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (399 KB)

    It is known that trellis-coded modulation (TCM) can give a significant coding gain without compromising bandwidth efficiency, by the concepts of signal set partition and trellis coding scheme. It is also known that block-coded modulation (BCM) can be used to approach closely the maximum energy saving that can be obtained by using the densest lattice over the rectangular lattice (QAM). In this pape... View full abstract»

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  • Optimal design parameters in capacity assignment for a broadband network

    Publication Year: 1991, Page(s):387 - 393
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (447 KB)

    A capacity assignment strategy for a broadband network is proposed and studied in this paper. This broadband network has a large channel capacity in its elements. It usually has two kinds of customers: one is queueable narrowband (NB), and the other is blockable wideband (WB) which needs real-time delivery. Besides the characteristics of these two types of traffic, since the improvement in the blo... View full abstract»

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  • Solution for packet switching of broadband ISDN

    Publication Year: 1991, Page(s):394 - 400
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (664 KB)

    A possible solution for the broadband ISDN is proposed. A new packet switch, denoted by DPPS (double phase packet switch), is found to be capable of performing well with low cost. DPPS consists of several baseline networks in parallel. DPPS is modular and can easily be expanded because of the recursive structure of baseline networks. Along with the simple and distributed control algorithm, the DPP... View full abstract»

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  • Synchronisation of random bit sequences: application to hitless switching

    Publication Year: 1991, Page(s):401 - 406
    Cited by:  Papers (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (431 KB)

    The paper deals with the synchronisation problem of random bit sequences in hitless, or errorless, switching in frequency diversity digital radio systems. After a short discussion of technical aspects of the switching system, the problem of synchronisation is defined. The sources of incorrect operation, i.e. of not finding synchronism and of finding it in a false position, are given. It is shown t... View full abstract»

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  • Decomposition of output queuing switches

    Publication Year: 1991, Page(s):407 - 416
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (789 KB)

    The paper introduces a simple technique to reduce the complexity of the output queuing switch with a speedup without either losing the self-routing characteristic or allowing performance degradation under nonuniform traffic patterns. Any of the output queuing switches with a speedup can be used as a basic switching element. The switching elements are then interconnected with the distributors in mu... View full abstract»

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  • Distributed double-phase switch

    Publication Year: 1991, Page(s):417 - 425
    Cited by:  Papers (3)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (710 KB)

    A packet switch architecture is proposed for the broadband ISDN. It is in three stages. The first stage consists of simple distributors which transfer the incoming packets to the later stages regularly and in balance. The next two stages carry out the routing; they are composed of small knockout switches. The authors model the switching system as an M/D/m queuing model and show that, when the load... View full abstract»

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  • Analysis and simulation of a hybrid modulation scheme for embedding data in amplitude-modulated signals

    Publication Year: 1991, Page(s):426 - 436
    Cited by:  Papers (1)  |  Patents (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (881 KB)

    Zero synchronous modulation (ZSM) is a novel hybrid modulation scheme which employs angle modulation to transmit a data signal in addition to analogue envelope modulation. The bandwidth of a ZSM signal is restricted to that of conventional DSB-AM by synchronising data with the occurrence of complex zeros of the analogue input. The theoretical basis of ZSM is discussed and a new algorithm is given ... View full abstract»

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  • Sounding techniques for wideband mobile radio channels: a review

    Publication Year: 1991, Page(s):437 - 446
    Cited by:  Papers (56)  |  Patents (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (806 KB)

    A major prerequisite to the specification and design of any wideband digital mobile radio system is a thorough knowledge of the propagation characteristics of the mobile radio channel. The various methods of channel sounding are reviewed, with both narrowband and wideband techniques being discussed. The advantages and limitations of each method are highlighted and the swept time-delay cross-correl... View full abstract»

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  • Measurement and modelling of wideband mobile radio channels at 900 MHz

    Publication Year: 1991, Page(s):447 - 457
    Cited by:  Papers (18)  |  Patents (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (882 KB)

    The complex bandpass impulse response of urban mobile radio channels is measured at 900 MHz using a swept time-delay cross-correlator channel sounder. The propagation data are analysed with particular relevance to the development of a representative channel simulation and production of parameters useful to systems engineers. In both cases, a two-stage characterisation of the data is used. A moving... View full abstract»

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  • Performance analysis of mobile packet radio networks in real channels with inhibit-sense multiple access

    Publication Year: 1991, Page(s):458 - 464
    Cited by:  Papers (35)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (449 KB)

    Coherent cumulation of interference signals is modelled in an environment of Rayleigh fading and log-normal shadowing under the influence of near-far effect. The interference model is used to investigate the performance of mobile packet radio networks using the inhibit-sense multiple access protocol. Numerical results are presented, indicating the effect of individual and combined propagation impa... View full abstract»

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  • Bit error probabilities of CPM signals in frequency-selective fading channels

    Publication Year: 1991, Page(s):465 - 472
    Cited by:  Papers (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (604 KB)

    The performance of continuous phase modulation (CPM) signals with an MSK-type receiver in the frequency-selective fading environment is investigated. The channel is characterised by its power delay profiles. The modulation index of CPM signals is restricted to 1/2 for coherent detection with an MSK-type receiver. The full system performance is analysed analytically and the numerical results for th... View full abstract»

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  • Differential detection of correlative encoded continuous phase modulation schemes using decision feedback

    Publication Year: 1991, Page(s):473 - 480
    Cited by:  Papers (5)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (537 KB)

    The authors generalise a differential detection technique, introduced elsewhere for a Gaussian minimum shift keying (GMSK) scheme, to include any correlative encoded continuous phase modulated (CECPM) signalling format. The proposed symbol-by-symbol receivers employ decision feedback to partially remove the effects of the destructive intersymbol interference (ISI) which corrupts the differentially... View full abstract»

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