By Topic

Signal Processing, 2004. Proceedings. ICSP '04. 2004 7th International Conference on

Date 31 Aug.-4 Sept. 2004

Go

Filter Results

Displaying Results 1 - 25 of 240
  • Improving the propagation characteristics of Boolean function and cheating immune secret sharing

    Page(s): 2389 - 2392 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (134 KB) |  | HTML iconHTML  

    An effective method for transforming Boolean functions that do not satisfy the propagation characteristics into ones that satisfy the criterion. Zhang X. M. and Pieprzyk J., (2001) constructed cheating immune secret sharing only for even integer. Such a method can be used to construct cheating immune secret sharing with high nonlinearity for any integer. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Adaptive audio digital watermark algorithm based on m-sequence modulation

    Page(s): 2401 - 2404 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (179 KB)  

    This paper presents an adaptive audio digital watermark algorithm based on m-sequence modulation. Firstly, the visually recognizable binary watermark image should be converted into the one-dimensional sequence by the algorithm. The sequence is permuted pseudo-randomly and is modulated by m-sequence. Then the digital audio signal is set into segments and the discrete wavelet transform is performed. Finally the modulated signal is embedded in the coefficients with relatively large absolute value on middle frequency range detail signal adoptively. The experimental results show that the watermark is imperceptible and the algorithm is robust to digital audio signal when attacked by low pass filter, re-quantified and so on. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • On modeling AS traffic generating characters

    Page(s): 2695 - 2699 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (246 KB) |  | HTML iconHTML  

    In this paper, we propose a model to depict AS characters based on Netflow data collected from a specified router. Our model is designed to depict AS in a way just like astronomy observation: the router as the Earth, the ASes as the stars and the traffic measured by Netflow at the router as the light observed by the Earth from different "stars". Our goal is to infer the visual size and daily behavior of each AS through the intensity and fluctuation of the observed traffic. Based on the assumption that each AS consists of independent hosts with the same traffic emission behavior and follows a mixed activation mechanism, our model is simple enough to be used in traffic engineering and traffic anomalies detection. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The chaos in the synchrony of abnormal oscillations in a pair of neurons coupled via gap junction

    Page(s): 2210 - 2213 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (172 KB) |  | HTML iconHTML  

    The synchrony of abnormally excitable neurons is a hallmark in epileptic seizure. In order to study the nonlinear oscillations in two neurons coupled via gap junction in epilepsy, the model of a pair of neurons is derived from Chay model that gives many kinds of abnormal oscillations in excitable neurons by three nonlinear variables dynamics equations. The synchrony between two electrically coupled excitable neurons is found and a theoretical effort is carried out to investigate the chaos in the synchronous oscillations of the membrane potentials by the Lyapunov exponent and the phase portrait. It is shown that synchronous abnormal oscillations of membrane potentials can occur when the coupling strength of gap junction is large enough and the concentration of Ca2 ions does not synchronize while the membrane potentials are synchronous and the coupling mechanism is chaotic. It is concluded that the synchrony and the chaos make birth to the new oscillations while disorder process such as epileptic seizure. The theoretical analysis may be helpful to investigate the mechanism of synchrony and the relationship between abnormal oscillations and gap junctions from nonlinear oscillatory points of view. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A new dual M-ary orthogonal modulation scheme

    Page(s): 1890 - 1893 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (190 KB)  

    A new modulation scheme called dual M-ary orthogonal modulation (DMOM) is proposed in this paper. By simultaneously sending one orthogonal sequence through the in-phase branch and the quadrature branch, respectively, this scheme can double the bandwidth efficiency of M-ary orthogonal modulation for a given sequence length M , meanwhile keeps a constant envelope. A ML-based noncoherent detection algorithm and its simplified version are also presented for the demodulation. Finally, the BER performance and computation cost of DMOM are compared with those of the existed QOM. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Combination of likelihood scores using linear and SVM approaches for text-independent speaker verification

    Page(s): 2261 - 2264 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (187 KB) |  | HTML iconHTML  

    In this paper, the text-independent speaker recognition system based on the adapted GMMs was established, and the speaker-independent background model and speaker-dependent models of cohort speaker sets were used to normalize the likelihood score. The approaches to combine likelihood scores using linear and SVM (support vector machine) method in score domain was proposed. The speaker verification experiments over telephone channels showed that based on the likelihood ratio of adapted GMMs system, combination of likelihood scores can improve the verification performance of baseline system using universal background model (UBM). Specially, the approach of score combination using SVM achieved the best performance. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A type of sensor to detect occupancy of vehicle berth in carpark

    Page(s): 2708 - 2711 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (221 KB) |  | HTML iconHTML  

    To provide accurate, real time car park space information, based on the vortex detection principle, a novel berth detector is designed for the parking guidance system. The berth-detecting algorithm is proposed according to the complicated practical car park situation via threshold method. The median filter technology is adopted in this algorithm to eliminate transient-upset signal. The experimental results show that the vortex berth detector has strong robustness under rapid time-varying temperature condition, and the algorithm is efficient and reliable. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Discrimination of severely noisy pathological voice with spectral slope and HNR

    Page(s): 2218 - 2221 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (188 KB) |  | HTML iconHTML  

    In this paper we tried to discriminate severely noisy pathological voice from normal ones based on two different parameters, spectral slope and ratio of energies in harmonic and noise components (HNR). The spectral slope was obtained by using a curve filling method and the HNR was computed from cepstrum. Speech data from normal peoples and patients were collected, then diagnosed and classified into three different categories (normal, relatively less noisy and severely noisy data). The mean and the standard deviation of the two different parameters were computed and compared to characterize and discriminate the severely noisy pathological voice from others. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Distributed adaptive OSWCA CFAR detector

    Page(s): 2082 - 2085 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (223 KB)  

    In the sense of likelihood ratio test (LRT), a weighted adaptive OSWCA CFAR detector using distributed sensors is proposed in this paper. In the scheme, a local test statistic, which is the ratio of its test sample level and a designated order statistic (OS) of its reference samples, is calculated by each sensor, and then each sensor transmits its local test statistic to the fusion center. At the fusion center, the final decision is made based on weighted cell averaging algorithm (WCA). Since the weights are adjusted according to different signal-to-noise/clutter ratio (SNR), adaptively, the proposed detector can be available in the case of that the target echo and noise/clutter that have different level for each sensor. Unlike many current distributed CFAR detectors, which assuming that all noise/clutter samples satisfy independent identical distributed (IID) and have same SNR for each sensor. Meanwhile, for a Rayleigh fluctuating target in Gaussian noise of unknown level, we obtain its closed-form expressions for the false alarm probability and the detection probability. The numerical analysis results indicate that the proposed OSWCA scheme can be available. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Automated hand shape verification using HMM

    Page(s): 2274 - 2277 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (185 KB) |  | HTML iconHTML  

    In this paper we present a method for identity verification based on matching of hand shapes. Our method first represents the shapes of hands by sets of ordered points. Then the contour of the hand is characterized by a features sequence consisting of two parameters: the radius and curvature at the contour points, MMM has proved a very successful tool for modeling and recognition sequence signal. So the hand shapes are compared using HMM. We apply a normalization score measurement to improve the classification ability and robustness. The experiment results show the effectiveness of our method and the correct verification rate can be above 90%. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Digital watermarking capacity analysis in wavelet domain

    Page(s): 2278 - 2281 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (238 KB) |  | HTML iconHTML  

    Capacity is an important property of digital watermarking. Research of image watermarking capacity is to study how much information can be hidden in an image. Recently, wavelet transform has been applied widely in watermarking research as its excellent multi-resolution analysis property. This paper realizes a content adaptive watermarking algorithm using Watson quantization matrix and noise visibility function (NVF), and discusses the capacity problem of watermarking in wavelet domain. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Multiuser detection based on quantum detection

    Page(s): 1898 - 1901 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (165 KB) |  | HTML iconHTML  

    The scheme based on quantum detection to solve the NP hard problem in conventional multi-user detection is proposed in the paper. The simulation results for optimal quantum multi-user detection is presented, and performance comparisons with classical techniques show an improvement when quantum detection is employed. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • MR brain image segmentation using a possibilistic entropy based clustering method

    Page(s): 2241 - 2244 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (221 KB) |  | HTML iconHTML  

    A novel pixel-intensity-based segmentation technique is presented for magnetic resonance (MR) brain images segmentation using possibilistic entropy clustering. A brief analysis of the problems of boundaries shifting and region blur in FCM based MR images segmentation is made, which reveals that the lack of robustness to noise and outliers and inappropriate membership assignment in intensity space lead to such problems. Within the framework of possibilistic entropy theory, the proposed algorithm inherits the merits of possibilistic theory and shows a great robustness to noise and outliers for class center estimation. It can also automatically control the resolution parameter during the clustering is progressing. Finally, the experiments of cerebrum region segmentation and lesion detection verify its effectiveness over the FCM algorithm. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Application of lifting scheme in pitch extraction for speech processing of cochlear implants based on characteristics of Chinese language

    Page(s): 2222 - 2225 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (183 KB) |  | HTML iconHTML  

    Pitch extraction and estimation are very important issues in speech processing. Although frequency-domain analysis can get a good precision, its complex computing and mass memory occupation make it hardly suitable for cochlear implants based on characteristics of Chinese language. In this article, lifting scheme is adopted, combined with pitch extraction algorithm, to extract fundamental frequency of simulated signal and real speech signal. Veracious result is obtained and advantages in memory occupation as well as computing speed are found, which shows the great potential of lifting scheme in the application of pitch extraction in speech processing strategy for cochlear implants based on characteristics of Chinese language. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • An STF-based chaos synchronization and its application to secure communication

    Page(s): 2379 - 2384 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (198 KB) |  | HTML iconHTML  

    The strong tracking filter (STF) is introduced as a new synchronization method for the chaotic communication systems with noise existing in both system and channel. STF improves the extended Kalman filter (EKF) which has been used widely in the chaotic communication. Compared with EKF-based method, the STF-based chaos synchronization technique is more robust to system model error and has smaller mean square error (MSE). View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Application of ICA in harmonic retrieval in chaotic noise

    Page(s): 2549 - 252. vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (179 KB) |  | HTML iconHTML  

    In this paper, we apply the independent component analysis (ICA) method to the retrieval of harmonic signal from chaotic noise. Our method utilizes the characteristic of ICA that can separate the mixed signals, which are statistic independent, although the chaotic noise was generated by some deterministic system in contrast to the previous methods that constrain the time or amplitude scale of signals, our method can separate the signals from the chaotic noise without such constraint and the knowledge of the deterministic system that generate the chaotic noise. The simulation study has shown that ICA method can extract very weak signal under some well known chaotic background. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • An eigenspace-based algorithm for adaptive antenna sidelobe cancellation

    Page(s): 2086 - 2089 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (183 KB) |  | HTML iconHTML  

    By combining the conventional algorithm for adaptive sidelobe cancellation and the eigenspace technique, this paper presents a novel algorithm for adaptive sidelobe cancellation. The weight vector of the novel algorithm is calculated by projecting the weight vector of the conventional algorithm into the interference subspace of the auxiliary channels' correlation matrix. The projection operation reduces the effect of the noise subspace on the weight vector. Compared to the conventional algorithm for adaptive sidelobe cancellation, the novel algorithm has a good cancellation performance and can rapidly converge. Computer simulation and real data processing results show that the algorithm is effective. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Audio watermarking based on psychoacoustic model and adaptive wavelet packets

    Page(s): 2518 - 2521 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (202 KB)  

    A novel watermarking scheme for audio authentication is proposed in this paper. The scheme combines the psychoacoustic model with wavelet packets to adaptively select the best basis for wavelet packet decomposition such that the subbands are closest to critical bands, given the temporal resolution and computational limit. The proposed method can adaptively control the watermarking strength in the wavelet packet domain according to psychoacoustic model, which ensures both transparency and sensitivity of the watermarking scheme. The amount of watermark inserted in different wavelet packet coefficient is based on current subband threshold generated by psychoacoustic model. Generally, in our scheme, one coefficient carries multi-bit watermark message, which corresponds to different tampers. The new scheme can authenticate the integrity of audio signals and simultaneously can locate the tampered region in temporal/frequency domain and decide the tampered extent, as well. Experimental results show that the proposed scheme has the desired property and good performance for audio authentication. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A scalable and oblivious digital watermarking for images

    Page(s): 2338 - 2341 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (276 KB) |  | HTML iconHTML  

    Scalable compression algorithms, such as JPEG, can compress images to different quality or resolution levels so that the target systems with different display capabilities, can display the image. Digital watermarking is widely used for protection of copyright and identification of ownership on digital images. It is desirable to have scalable watermarking systems, where the watermark is detectable when the watermarked image is at low quality or low resolution levels. This paper presents an oblivious block-based spread-spectrum-like watermarking system which is robust against scalable JPEG compression, cropping and shifting. The system is secure against the common watermarking attacks. Experimental results support these claims. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Noise suppressing by wavelet transform in seismic data processing

    Page(s): 2553 - 2555 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (183 KB) |  | HTML iconHTML  

    This paper gives a new approach to suppress noise in seismic data. According to the time-frequency local characteristics of wavelet transform and the optimal filtering characteristics of KL transform, we have advanced this approach. On the basis of the fact that the noise energy is different from reflection energy in each frequency range, prestack seismic data is divided into different frequency band by wavelet transform first, and then it is filtered by KL transform. Synthetic and real data processing results show that the method can desirably eliminate noise. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Fragile authentication watermark combined with image feature and public key cryptography

    Page(s): 2286 - 2289 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (293 KB)  

    In this paper, a new invisible watermarking technique can localize tampered areas for image authentication is proposed, which skillfully combined with image feature and public key cryptography. A logo is embedded based on image feature and secret key as watermark for the integrity verification and localized tamper detection. The watermark extraction uses a public key corresponds to the private key in embedding procedure. The new scheme not only can resolve the security problem tailing most existing scheme to this day, but also permits public detection of the watermark by any person without the secure exchange of a secret key, which is very important in many applications such as trusted camera and Web image authentication. Theoretical analysis and experiment results demonstrate its outstanding performance above. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • On an adaptive ICA method with application to biomedical image analysis

    Page(s): 2245 - 2248 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (219 KB) |  | HTML iconHTML  

    Conventional ICA algorithms typically model the probability density functions of the underlying sources as highly kurtotic or symmetric. However, when source data violate the assumptions (e.g. low kurtosis), the conventional ICA methods might not work well. Adaptive modeling of the underlying sources thus becomes an important issue for ICA applications. This paper proposes the log Weibull model to represent skewed distributed sources within the infomax framework and further introduces an adaptive ICA method. The central idea is to use a two-stage separation process: 1) conventional ICA used for all channel sources to obtain initial independent source estimates; 2) source density estimate-based nonlinearities adaptively used for the "refitting" separation to all channel sources. The ICA algorithm is based on flexible nonlinearities of density matched candidates. Our simulations demonstrate the effectiveness of this approach. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Research of simulation method by means of inversion from airborne SAR data to spaceborne MPC SAR data

    Page(s): 2179 - 2181 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (295 KB) |  | HTML iconHTML  

    A method to simulate spaceborne MFC SAR data is presented in this paper, and a simulation example of spaceborne system is given also. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Fusion and shape retrieval of area target based on sparse sampling

    Page(s): 2489 - 2493 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (212 KB) |  | HTML iconHTML  

    The paper introduces the image moments and deduced shape factors into the fusion and shape retrieval of area target based on sparse sampling of boundary. The fusing rules for area target is established and a merging algorithm of sampling series used for shape retrieval is given. Simulation of fusion and retrieval shows that our rules and algorithm are effective and feasible. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Reduced distortion bit-modification for LSB audio steganography

    Page(s): 2318 - 2321 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (243 KB) |  | HTML iconHTML  

    In this paper, we present a novel high bit rate LSB audio data hiding method that reduces embedding distortion of the host audio. Using the proposed two-step algorithm, hidden bits are embedded into the higher LSB layers, resulting in increased robustness against noise addition. In addition, listening tests showed that perceptual quality of watermarked audio is higher in the case of rite proposed method than the perceptual quality obtained using the standard LSB method. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.