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Intelligent Signal Processing and Communication Systems, 2004. ISPACS 2004. Proceedings of 2004 International Symposium on

Date 18-19 Nov. 2004

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Displaying Results 1 - 25 of 188
  • MP3-resistant music steganography based on dynamic range transform

    Page(s): 266 - 271
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (379 KB) |  | HTML iconHTML  

    In this paper, we present a novel audio steganography scheme for embedding high-capacity covert data in a music carrier, where the carrier is first filtered into a sub-signal, insensitive to the human auditory system, using a dynamic range filter, then the sub-signal is downsampled and transformed to a 2D arrangement (image), and finally the image is transformed to a wavelet domain singular value decomposition (SVD) on which a quantization-index-modulation process is applied for embedding the covert data. The proposed scheme, due to its indirect embedding on the singular values of the dynamic range filtered data in the visual domain, possesses a high and flexible embedding capacity and a superb MP3 robustness while retaining an excellent inaudibility. The MP3 robustness and the imperceptibility are further enhanced by adaptively modeling the quantization parameters, based on the statistics within subbands. The embedded data extraction is also secure and oblivious. View full abstract»

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  • Digital watermarking for color video using a nonlinear filter in detection process

    Page(s): 278 - 282
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (339 KB) |  | HTML iconHTML  

    A new watermarking method for color video, using a nonlinear digital filter, is proposed. This method is based on Haitsma and Zhao's methods which embed watermark signals into the luminance mean series, but newly introduce a nonlinear digital filter, named a component separating filter (CS filter), in the detecting process to improve the detection performance. The CS filter can effectively extract the small-amplitude watermark signals on the mean series without being affected by an abrupt shot change. Moreover, it is shown that higher performance is realized by embedding into the color difference signal instead of the luminance. Computer simulations verify its performance. View full abstract»

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  • Improved low bit-rate MPEG-4 video coding with spatio-temporal rate control

    Page(s): 116 - 120
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (388 KB) |  | HTML iconHTML  

    In the case of a video delivery system which is constructed by a constant bit-rate channel, the encoder must send a constant number of bits per unit time period. Therefore, the number of bits used in encoding must be regulated by the rate control algorithm. Basically, the rate control of a video signal such as MPEG-4 is realized by adaptive quantization. However, since adaptive quantization has the limitation of bit regulation, temporal resolution conversion is also introduced. The temporal resolution conversion is effective for decreasing the number of bits for encoding, however the conversion causes a decrease in temporal resolution. Decreasing the temporal resolution results in jerky degradation. In this paper, in order to keep the temporal resolution, we introduce the spatial resolution conversion for rate control algorithm. Moreover, we show how to choose the temporal resolution conversion or the spatial resolution. Thus, the proposed method realizes low bit-rate video coding while preserving the original frame-rate. View full abstract»

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  • A bit allocation scheme by controlling code rate for closed-loop V-BLAST OFDM system with soft channel decoding

    Page(s): 52 - 57
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (415 KB) |  | HTML iconHTML  

    In this paper, we present a bit allocation scheme for a closed-loop MIMO-OFDM (multiple input multiple output-orthogonal frequency division multiplexing) system using V-BLAST (vertical-Bell laboratories layered space-time) detector with soft channel decoding. A fully adaptive modulation and coding scheme may provide the optimal performance, but requires excessive feedback information. Instead, the proposed scheme controls the code rate of the channel coding and assigns the same modulation and coding to the set of selected sub-channels, which greatly reduces the feedback overhead while achieving good performance. Simulation results show that the proposed scheme with minimal feedback provides significant performance improvement over the conventional bit allocation schemes. View full abstract»

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  • Steps towards 'undigital' intelligent image processing: real-valued image coding of photoquantimetric pictures into the JLM file format for the compression of portable lightspace maps

    Page(s): 398 - 403
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (503 KB) |  | HTML iconHTML  

    Recent advances in intelligent signal processing have made it possible to capture high dynamic range images which are better represented as an array of real numbers rather than the current convention of an array of integers. This paper proposes a solution to address the need for real, rather than just integer, image coding and file formats. Additionally, we propose that the real-valued data be linear in photoquantity (the quantity of light received by the camera) to avoid the image misrepresentation that occurs when a camera's non-linear dynamic range compressor and a display's dynamic range non-linear expander do not match. We present two novel image formats that achieve this: the portable lightspace map (PLM) and its compressed version the JPEG lightspace map (JLM), that builds upon the JPEG compression scheme. The results of various compression levels for real-valued data and their corresponding file sizes are reported. View full abstract»

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  • Information theoretic comparisons of training based channel estimation and semi-blind estimation in fading channels with memory

    Page(s): 6 - 10
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (393 KB) |  | HTML iconHTML  

    In this paper, we analyze and compare the semi-blind estimation scheme with the conventional training based scheme in linear block fading channels with memory. Our results show that the performance of semi-blind estimation in terms of the channel mutual information and the Cramer-Rao bound is superior to the conventional training based scheme, but the performance gain diminishes as the signal-to-noise ratio (SNR) increases. We have derived the optimal lengths of training sequence for both estimation schemes in terms of the mutual information of the channel. Provided that the length of the training sequence used for channel estimation is optimized, we found that by using either channel estimation scheme, the mutual information of the channel drops sharply with the memory of the channel at low SNR. On the contrary, the mutual information drops only mildly with the memory of the channel at high SNR. View full abstract»

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  • A study on the regulations concerning base stations for next-generation mobile communications networks in Korea

    Page(s): 717 - 722
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (389 KB) |  | HTML iconHTML  

    Mobile communications services, which offer one way to realize the informed society of the 21st century, have developed rapidly worldwide. With the commercialization of CDMA 2000-1× late in 2000, a high-speed wireless Internet, based on a mobile communication network, appeared in Korea. This will develop into the next-generation of mobile communications (4G) with faster transmission of increased volumes of data in the future. The new cell layout requires the cellular configuration of 4G and the services 4G have to offer a more universal mobile communication service and helps to reduce the digital divide. We would need legislation with respect to base stations and for building the mobile communication networks, as well as the optimization of mobile communication systems. In this study, in order to provide 4G, I examined and analyzed the current laws related to licensing and operating a mobile communication base station in Korea. View full abstract»

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  • Design of address generation unit for audio DSP

    Page(s): 616 - 619
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (328 KB) |  | HTML iconHTML  

    The paper presents an address generation unit (AGU) for an audio DSP. The proposed AGU employs an enhanced FFT address generation unit (FAGU) that automatically calculates the butterfly input/output data addresses. The FFT is one of the key tasks for the modified discrete cosine transform (MDCT) mostly used in various audio algorithms. The number of FFT computation cycles can be reduced by the proposed FAGU. The proposed AGU has been synthesized using the SEC 0.18 μm standard cell library. The proposed FAGU has been implemented and the gate count is 1,523. The size is decreased about 73% compared with the FAGU that we have previously proposed. View full abstract»

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  • A supplementary feature for speaker verification in constrained room acoustics

    Page(s): 189 - 192
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (321 KB) |  | HTML iconHTML  

    The paper describes a preliminary experiment to find a supplementary feature for speaker verification. In conventional speaker verification systems, spectral features, such as the Mel frequency cepstral coefficient (MFCC), are used universally for all speakers. For some specific applications demanding high security, however, the system also needs to adopt speaker specific supplementary features. Assuming that verification is done in a specified room environment, we analyze the effect of the room response on speaker verification. Simulation results show that the additional supplementary feature is crucial for improving system performance. View full abstract»

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  • Joint fine time synchronization and channel estimation for MIMO-OFDM WLAN

    Page(s): 463 - 467
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (331 KB) |  | HTML iconHTML  

    Fine time synchronization for the OFDM (orthogonal frequency division multiplexing) system is carried out by taking correlation between the received sequence and a reference sequence. This conventional method shows unsatisfactory performance in a WLAN (wireless local area network) environment due to the large value of RMS delay spread. The paper proposes an algorithm to improve the performance of the estimator by exploiting the characteristics of the channel. We also present a channel estimation algorithm in the time domain for MIMO-OFDM (multiple-input multiple-output OFDM) with the same complexity as that in a single antenna system. The simulation results show: (1) for symbol time synchronization, the probability of incorrect timing in the proposed algorithm is hundreds of times lower than that in the conventional algorithm; (2) for channel estimation, with the use of two consecutive training sequences as in standard IEEE 802.11a, there is 3 dB decrease in SNR to achieve the same MSE as in the case of only one training sequence. View full abstract»

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  • A generic CAD tool for efficient NoC design

    Page(s): 728 - 733
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (474 KB) |  | HTML iconHTML  

    Network on chip (NoC) using packet switching is a solution to cope with complex system on chip (SoC) communications. However, tools are needed to help designers to deal with NoC. The two elements composing an NoC are its routers and its network interfaces (NI). We focus on the specification and generation steps of the μspider NOC design flow that addresses what we consider as the main features of a realistic and useful NoC. Firstly, the synthesis tool is based on a generic router through a user friendly design interface. Secondly, it supports the management of different levels of quality of service (QoS), allowing a guaranteed throughput (GT) service in addition to a classical best effort (BE) service. Finally, it can be tuned to handle asynchronous communications. The paper presents the router architecture and its various custom characteristics. We show the tradeoff between a hierarchical QoS channel implementation and the performance of the system. View full abstract»

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  • Automatic segmentation of objects of interest in video: a unified framework

    Page(s): 375 - 378
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (362 KB) |  | HTML iconHTML  

    Automatically extracting interesting objects from videos is a very challenging task. Traditional video segmentation algorithms assume that objects of interest are the moving objects, whereas they neglect the fact that some stationary objects are also likely to attract human interest. To remove this limitation, this study provides a unified video object segmentation framework by taking human visual attention perception into account. It is implemented by three major steps. First, the JSEG algorithm (Y. Deng et al, IEEE Trans. Pattern Anal. Machine Intell., vol.23, p.800-810, 2001) is adopted to partition each frame into homogenous regions. Following that, based on a number of visual features that have been proven to be able to influence attention, two visual attention models are proposed to calculate the attention value for each region. Finally, a combination of the spatial segmentation and the visual attention models produces all the objects of interest with and without motion. Simulation results on standard video sequences demonstrate its effectiveness. View full abstract»

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  • A delay diversity receiver for CDMA cellular systems

    Page(s): 468 - 471
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (341 KB) |  | HTML iconHTML  

    A delay diversity receiver for code division multiple access (CDMA) cellular systems is proposed and analyzed. It is shown that the proposed receiver can achieve a remarkable diversity gain with reasonable cost and complexity from the perspective of outage probability. The proposed receiver can find its application to IS-95/cdma2000 1x base stations with simple modifications. View full abstract»

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  • Nonlinear state space embedding features and their application to robust speech segmentation

    Page(s): 317 - 320
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (322 KB) |  | HTML iconHTML  

    The aim of our research is to develop features from a state space embedded signal useful for high resolution and robust real-time speech segmentation. Since the set of state-space trajectories of a system can completely describe the system, state space embedding of a signal is typically used to study qualitatively any nonlinearities of the system generating a signal. However. while it may be easy for one to observe patterns in the state space trajectories of a system, it is often difficult to quantify what is observed. Two novel features are extracted from a state space embedded signal using concepts from differential geometry. These features are computed iteratively on the one-dimensional speech signal and they completely characterize the state space trajectories formed by the signal. The results obtained show that these features are particularly useful for classifying voicing states and can detect these phoneme boundaries with a resolution of four samples. View full abstract»

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  • Detection of occluded multiple objects using occlusion activity detection and object association

    Page(s): 100 - 105
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (476 KB) |  | HTML iconHTML  

    This paper proposes the detection of occluded moving objects using occlusion activity detection and an object association algorithm. When multiple objects are occluded between them, a simultaneous feature based tracking of multiple objects using tracking filters fails. To estimate feature vectors such as location, color, velocity, and acceleration of a target is a critical factor affecting the tracking performance and reliability. To resolve this problem, the occlusion activity detection and object association algorithm are addressed. The occlusion activity detection method provides the occlusion status of next state using the Kalman prediction equation. By using this predicted information, the occlusion status is verified once again in its current state. If the occlusion status is enabled, an object association technique using a partial probability model is applied. Using these algorithms, we can obtain the reliable center points of occluded objects respectively. For an experimental evaluation, the image sequences for a scenario in which three rectangles are moving within the image frames are made and evaluated. Finally, the proposed algorithms are applied to real image sequences. Experimental results in a natural environment demonstrate the usefulness of the proposed method. View full abstract»

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  • Low-band extension of CELP speech coder by harmonics recovery

    Page(s): 147 - 150
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (350 KB) |  | HTML iconHTML  

    Most of the telephone speech being transmitted in public networks is bandlimited to 300-3400 Hz. Narrowband speech is lacking in the information from low-band (0-300Hz) and high-band (3.4-8kHz) that are found in wideband speech (0-8kHz). As a result, narrowband speech is characterized by the reduced intelligibility and muffled quality, and degraded speaker identification. Therefore a bandwidth extension method, one of the techniques providing wideband speech quality without any additional information has been explored. By using the conventional technique to recover the missing high-band speech, we estimated the spectral envelope and the excitation for high-band using statistical recovery and spectral folding, respectively. In addition, we proposed an approach that exploits the harmonic synthesis method for the reconstruction of low-band speech over the CELP speech coding. Spectral distortion measurement and listening test are performed to evaluate the proposed method. Evaluation with synthesized speech shows the quality improvement. View full abstract»

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  • Measurement of skin texture using genetic image analysis

    Page(s): 787 - 791
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (369 KB) |  | HTML iconHTML  

    A binarization method of images for presumption of skin age is proposed using genetic programming (GP) which is an evolutionary computing method. Skin age can be estimated by skin texture, but it is difficult to binarize skin images owing to individual differences. Therefore, results obtained by genetic image processing were achieved with consideration of individual differences, and good results were obtained. The fast Fourier transform (FFT) was performed on skin images and a classification experiment was carried out by a neural network (NN) as a comparative experiment. However it is demonstrated that an effective classification result was not obtained by FFT and NN compared to our approach. View full abstract»

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  • F-SEONS: a second-order frequency domain algorithm for convolutive source separation in noisy environments [speech recognition applications]

    Page(s): 612 - 615
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (292 KB) |  | HTML iconHTML  

    Convolutive source separation is a problem of restoring original unknown sources from multiple sensor signals that are modelled as convolutive mixtures of mutually independent sources. It is a fundamental problem which plays a critical role in cocktail party speech recognition. Most of existing methods neglected the effect of sensor noise in the model of convolved mixtures. In this paper, we consider the case of noisy data and present a method of source separation, F-SEONS, which jointly exploits the nonstationarity and temporal structure of sources in the frequency-domain. Numerical experiments, comparing to other methods, confirm the high performance of our proposed method. View full abstract»

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  • Hybrid mean adaptive center weighted median filter for color sensor denoising

    Page(s): 321 - 326
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (547 KB) |  | HTML iconHTML  

    The paper describes a novel method for removing sensor noise from images acquired using digital cameras at high ISO settings. The problem lies in the fact that the algorithm must deal with hardware-related sensor noise that affects certain color channels more than others and is thus non-uniform over all color channels. An adaptive signal equalization mean and median hybrid filter is formulated and experimental results are presented with an analysis of the performance of the filter in comparison with other standard noise reduction filters. View full abstract»

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  • The design of signal scaling for a 16-QAM multi-carrier transceiver realized on a DSP platform

    Page(s): 767 - 770
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (295 KB) |  | HTML iconHTML  

    A signal scaling design procedure, to obtain the best noise performance for a 16-QAM discrete multi-carrier transceiver, realized on a digital signal processing (DSP) platform, is presented. The experimental results demonstrate that under the proper scaling, the bit error rate (BER) of the multi-carrier transceiver can approach a very small value. The proposed signal scaling method can be applied to other DSP based multicarrier communications systems. View full abstract»

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  • Spectral analysis of frequency domain multiplication-free adaptive filter with the MDFT

    Page(s): 309 - 312
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (305 KB) |  | HTML iconHTML  

    The paper analyses the spectrum of a frequency domain multiplication-free adaptive filter (FDMAF) using a modified discrete Fourier transform (MDFT) pair. The proposed FDMAF employs the MDFT and differential pulse code modulation in an input part and the reference input vectors are used in an update equation for the adaptive filter coefficients. Also, it can be simply controlled by adjusting the amplitude of the MDFT pair output signals and can obtain an output signal with stable convergence characteristics and without accumulated error. The condition used to analyse the algorithm has zero-mean, wide-sense stationary and white Gaussian noise. View full abstract»

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  • Plane identification and segmentation from uncalibrated stereo based on evolutionary approach

    Page(s): 80 - 83
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (347 KB) |  | HTML iconHTML  

    Planes are widely used in various vision tasks due to their abundance especially in man-made environments. Assuming an uncalibrated stereo image acquisition system, we propose a new plane identification and segmentation algorithm using an evolutionary approach. The proposed algorithm enables faster and more robust estimation of the plane since it progressively searches the best solution in a guided direction. Experimental results show that the proposed algorithm has higher performance than the existing method. View full abstract»

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  • Low-complexity joint estimation of frequency offset and carrier phase for M-ary PSK

    Page(s): 639 - 644
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (448 KB) |  | HTML iconHTML  

    We investigate the design of three low-complexity joint estimation algorithms (LJEAs) for frequency offset and carrier phase. The principles of the proposed LJEAs are based on the linear interpolation of correlation values in the main-lobe of the frequency and phase spectra of the received signal. With these algorithms, the estimation ranges, Δfd×Ts, are less than 1/2Ns and 1/Ns which are comparable to conventional algorithms (fd is the frequency offset, Ts is the symbol period, Ns is the burst length). The proposed LJEAs require only 2Ns or 4Ns complex multiplications which are very simple compared with conventional algorithms. Nevertheless the estimation accuracies of the LJEAs are as good as those of the conventional algorithms. View full abstract»

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  • A study on implementation of table generating system for data broadcasting based on ACAP [advanced common application platform]

    Page(s): 414 - 418
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (344 KB) |  | HTML iconHTML  

    Digital broadcasting has the advantage of better quality images and sound, more consumer choice, electronic program guides, and so on. Moreover consumers are able to enjoy services actively. The implemented system generates the PSIP, PSI, and AIT stream for terrestrial data broadcasting. This system is composed of two parts. One part is the streaming controller. It makes metadata for PSIP, PSI and AIT according to pre-defined XML schema. The other part is the table generator. It generates a transport stream packet from the transmitted metadata. The implemented system receives XML documents. Therefore, it is available in any broadcasting system, if the user converts the metadata. View full abstract»

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  • An efficient indexing method for similarity searches in high-dimensional image databases by principal axis analysis

    Page(s): 409 - 413
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (358 KB) |  | HTML iconHTML  

    This paper is focused on the design of the indexing structure for high-dimensional image databases by principal axis analysis. Firstly, we present the method of constructing the projection line with minimum inertia by principal axis analysis. Secondly, the proposed filtering mechanism, based on the projection scores of the database vectors, is presented. Then follows a method to enhance the discriminatory power of the approximations by incorporating the projection scores on multiple principal axes. Finally, some experimental tests to illustrate the effectiveness of our method are shown. View full abstract»

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