The tutorial starts with an introduction of digital image interpolation, and single image super-resolution. It continues with the definition of various image interpolation performance measurement indices, including both objective and subjective indices. The core of this tutorial is the application of covariance based interpolation to achieve high visual quality image interpolation and single image super-resolution results. Layer on layer, the covariance based edge-directed image interpolation techniques that makes use of stochastic image model without explicit edge map, to iterative covariance correction based image interpolation. The edge based interpolation incorporated human visual system to achieve visually pleasant high resolution interpolation results. On each layer, the pros and cons of each image model and interpolation technique, solutions to alleviate the interpolation visual artifacts of each techniques, and innovative modification to overcome limitations of traditional edge-directed image interpolation techniques are presented in this tutorial, which includes: spatial adaptive pixel intensity estimation, pixel intensity correction, error propagation mitigation, covariance windows adaptation, and iterative covariance correction. The tutorial will extend from theoretical and analytical discussions to detail implementation using MATLAB. The audience shall be able to bring home with implementation details, as well as the performance and complexity of the interpolation algorithms discussed in this tutorial.

An area efficient switched capacitor charge pump based 2ntimes voltage converter constructed by cascading n units of identical cells with cross-coupled charge pump is proposed and is implemented with a boosting dynamic circuit to provide level shifting. The proposed charge pump can be implemented using standard high-voltage CMOS process. Simulation result of a 4times charge pump based on 0.35 mum CMOS technology is presented to demonstrate the effectiveness of the proposed circuit.

Automatic modulation recognition (AMR) is an expert in modulation type identification. Many existing algorithms attempt to recognize the modulation candidates using phase and magnitude feature extraction. Performance is a major drawback of this feature extraction under noisy environment. In this paper, we proposed a new algorithm using a modified Chi-squared test on clustered received signals as components to its performance function. Simulations show that even under low SNR environment, our proposed algorithm achieved higher recognition rate than other existing algorithms.

The H.264 video coding standard significantly outperforms previous standards in terms of coding efficiency. However, this comes as a cost of extremely high computational complexity due to mode decision where variable block size motion estimation (ME) is employed. In this paper, we propose an efficient algorithm to jointly optimize mode decision and ME. A theoretical analysis is performed to study the sufficient condition to detect all-zero blocks in H.264, and thus adaptive thresholds are derived to early terminate mode decision and ME. Besides the aforementioned early termination technique, the proposed algorithm also introduces temporal-spatial checking, thresholds based prediction and monotonic error surface based prediction methods to skip checking unnecessary modes. Experimental results demonstrate that the proposed algorithm can significantly reduce the computational complexity of H.264 encoding while maintaining almost the same rate distortion (RD) performance as the original encoder

This paper presents a novel efficient algorithm to reduce redundant DCT and quantization computations for H.264 encoding. A theoretical analysis is performed to study the sufficient condition for DCT coefficients to be quantized to zeros in H.264. As a result, a more tight sufficient condition is derived to early detect all-zero 4x4 DCT blocks. Compared with other algorithms, the proposed algorithm provides a more precise and efficient condition to predict all-zero DCT blocks. The experimental results demonstrate that the proposed algorithm outperforms other algorithms in terms of all the evaluated performances.

This paper proposes a novel analytical model to predict zero quantized DCT coefficients for fast video encoding. The dynamic range of quantized DCT coefficients are analyzed and a threshold scheme is derived in order to determine DCT and quantization computations to be skipped without video quality degradation. The proposed model is compared with other models in the literature. Experimental results demonstrate that the proposed analytical model can greatly reduce the computational complexity of video encoding without any performance degradation, and outperforms other models

This paper proposed an ESPRIT based 2D joint direction and polarization estimation algorithm that does not require a separate pairing algorithm, thus does not suffer from incorrect pairing problem as existing algorithms in literature. Simulation results have shown that the proposed algorithm can achieve accurate and stable estimation results, and can potentially save the computational complexity of the estimation problem.

A higher-order statistics based minimal transmit redundancy space-time FIR precoder-blind equalizer is proposed. For most block based transmission systems such as OFDM, a long guard period, which is longer than or equal to the channel order, is required to avoid inter-block interference. This guard period is a type of redundancy which consumes valuable bandwidth. The blind equalizer that we have proposed can blindly equalize the received precoded signal without the long guard period requirement. Simulation results have shown that the BER performance gain increases as more received data are used to design the equalizer which allows accurate estimation of the cumulant matrices. The proposed algorithm was also shown to be robust toward channel order overestimation.

Discrete cosine transform (DCT), quantization (Q), inverse quantization (IQ) and inverse DCT (IDCT) are the building blocks in video coding standards. A lot of computations are required to perform the DCT, Q, IQ, and IDCT operations. With this concern, a novel statistical model based on Gaussian distribution is proposed to predict zero quantized DCT (ZQDCT) coefficients in this paper to reduce the computational complexity of video encoding. Compared with other widely used models in the literature, the proposed model can achieve the best real time performance. Experimental results demonstrate that the proposed statistical model is superior to others in terms of processing speed at the expense of negligible degradation of video quality.

A novel technique is proposed to reduce the computational complexity of discrete cosine transform (DCT)-based video encoders. The proposed method merges the DCT and quantization into a single procedure, which is referred to as the novel quantized DCT (NQDCT), such that the DCT output does not need to be explicitly quantized. Thus, a lot of computations related to quantization can be saved. The video encoder's performance using NQDCT is evaluated by comparing it with those using the traditional separate DCT and quantization method and the quantized DCT (QDCT) method. Simulation results demonstrate that the proposed NQDCT outperforms the other two methods in improving the real-time performance for video encoding.

This paper presents a novel efficient prediction algorithm to reduce redundant discrete cosine transform (DCT) and quantization computations for H.264 encoding optimization. A theoretical analysis is performed to study the sufficient condition for DCT coefficients to be quantized to zeros. As a result, three sufficient conditions corresponding to three types of transform and quantization methods in H.264 are proposed. Compared with other algorithms in the literature, the proposed algorithm derives more precise and efficient conditions to predict zero quantized DCT coefficients. Both the theoretical analysis and experimental results demonstrate that the proposed algorithm is superior to other algorithms in terms of the computational complexity reduction, encoded video quality, false acceptance rate, and false rejection rate.

Abstract-A systematic method for designing a finite-impulse response (FIR) zero-forcing equalizer (ZFE) of the space-time modulated code (STMC) system based on nonmaximally decimated filterbank is proposed. The physical channel considered is assumed to be multiple-input-multiple-output (MIMO) with intersymbol interference (ISI) and space-time correlated noise. STMC is a space-time block code (STBC) system. Most of the STMC systems require a long guard period to avoid interblock interference (IBI), but, with the proposed equalizer, the length of the guard period is greatly reduced. This can enhance the spectral efficiency of the STMC especially when the channel dispersion is large. The existence conditions for FIR ZFE of the STMC system were derived. These include the maximal code rate STMC for a given channel and the minimal filter order of the FIR ZFE. For a given STMC precoder, the equalizability of the system was verified. The solution of FIR ZFE of STMC was parameterized, which allows the design of optimal FIR ZFE through unconstrained optimization. It is further shown that FIR ZFE could be improved by adding a simple permutation in the system. Design examples and simulation results were presented to evaluate the proposed design method.

This paper investigates a novel active buffer management scheme, "Jitter Detection" (JD) for gateway-based congestion control to stream multimedia traffics in packet-switched networks. The quality of multimedia presentation can be greatly degraded due to network delay variation or jitter when transported over a packet-switched network. Jitter degrades the timing relationship among packets in a single media stream and between packets from different media streams and, hence, creates multimedia synchronization problems. Moreover, too much jitter will also degrade the performance of the streaming buffer in the client. Packets received by the client will be rendered useless if they have accumulated enough jitter. The proposed active buffer management scheme will improve the quality of service in multimedia networking by detecting and discarding packets that accumulated enough jitter, such as to maintain a high bandwidth for packets within the multimedia stream's jitter tolerance. Simulation results have shown that the proposed scheme can effectively lower the average received packet jitter and increase the goodput of the received packets when compared to random early detection (RED) and DropTail used in gateway-based congestion control. Furthermore, simulation results have also revealed that the proposed scheme can maintain the same TCP friendliness when compared to that of RED and DropTail used for multimedia streams.

A special class of linear precoder-equalizer pair with equalizers formed by simple tapped delay lines is proposed. With this special equalizer structure, the equalizer of this system not only can enjoy the minimal implementation complexity, but also can avoid the noise amplification effect. Moreover, using nonmaximally decimated filterbank structure, this precoder-equalizer pair is proven to be able to guarantee intersymbol interference (ISI)-free communication by zero-forcing approach, even if spectral nulling exists in the physical channel. Another advantage of this system is that the length of the guard period introduced by the precoder can be any positive integer values, thus the guard period can be designed to maximize the spectral efficiency by selecting it to be as short as one symbol per block of transmitted signal. A systematic method for designing a minimal transmit power finite-impulse response (FIR) precoder under the proposed precoder-equalizer pair structure is presented. Under the ISI channel with independent additive white Gaussian noise, the design of this minimal transmit power FIR precoder is shown to be a minimum mean square error precoder design. Simulation results are presented to illustrate the performance of the proposed precoder-equalizer structure and that of the transmit power minimized precoder.

The design of the FIR filter with constraints in the frequency domain and/or the time domain is considered. We further consider the design specification without an explicitly specified transition band. A constrained eigenfilter is proposed to design the FIR filter with various design constraints, and without a transition band specification. We have suggest the possible design tradeoff between transition band bandwidth and the ripple size of the filter. The proposed algorithm can design filters with optimal tradeoff between transition band bandwidth and the peak constrained ripple size. The eigenfilter formulation further allows the filter design specification to incorporate time domain constraints. Various design examples are presented to illustrate the versatility of the digital filter obtained by the proposed filter design method.

An iterative joint FIR precoder-equalizer optimization algorithm for MIMO ISI channel is proposed. This algorithm provides a suboptimal solution of the FIR zero-forcing precoder (ZFP) and equalizer (ZFE) for the space-time modulated code (STMC) system. Although serval joint precoder-equalizer design methods for MIMO ISI were proposed, existing design methods require a long guard period, which is larger than or equal to the channel order, to be inserted in the transmitted signal for avoiding the inter-block interference (IBI). This reduces the spectral efficiency of those systems. In this paper, we adopted the STMC structure, which does not require a long guard period. Using the FIR LS ZFE designing techniques previously proposed by us, we proposed a FIR LS ZFP design method. By combining the proposed ZFP design method with the ZFE design method, we propose an iterative joint FIR precoder-equalizer optimization algorithm. Although the iterative algorithm can only provide the suboptimal precoder-equalizer design, simulation results showed that substantial performance gain can be obtained when comparing with those cases without the joint precoder-equalizer design.

The paper discusses a novel algorithm (new quantized DCT - NQDCT) that combines the DCT with the quantizer to achieve energy scalability in a DCT based multimedia codec. A thorough analysis of the algorithm is presented. Simulation results show that a 15% reduction in computational energy can be obtained in an implementation of an MPEG coder over a wide range of bit-rate when compared to that of the standard MPEG coder test model.

The paper investigates a modified version of an active buffer management scheme, detection (JD), for gateway-based congestion control to stream layered multimedia multicast traffic over IP networks. The JD scheme works well with traditional congestion control schemes, such as RED, which are used for non-multimedia traffic. At the same time, the JD scheme improves the quality of service in multimedia networking by detecting and discarding useless packets that accumulated large enough jitter, in order to maintain a high bandwidth for packets within the jitter tolerance of the multimedia player. The paper also considers multicast with a layered coding scheme for multimedia streaming quality improvement. Differentiated from the traditional JD scheme, we propose to preserve the base layer traffic with best effort when passing through the gateway. The priority of dropping decisions is given to those higher level layer (enhancement layer) multicast packets. Queuing analysis has been performed to evaluate the efficiency of the proposed scheme. Simulations by NS2 were also performed and the results show that the proposed scheme can provide better quality than that using RED in gateway-based congestion control for multimedia traffic.

This paper proposes a spectral subtraction based speech enhancement algorithm that improves computer based speech recognition. Speech recognition can not be improved by traditional spectral subtraction techniques because of the associated artifacts, such as musical noise. This paper proposes a tonal noise suppression algorithm which can he used for accurate psychoacoustic model parameter estimation. Simulation results show that the spectral subtraction based speech enhancement algorithm with psychoacoustic masking produced by the estimated parameters produces high quality clean speech, which can be used as preprocessing tools to enhance the speech recognition rate. Simulation results using Aurora 3 database are presented.

This paper proposes a "minimum redundancy tree" (MRT) for key distribution in secure multicast. The MRT is optimal in terms of minimum rekeying costs by keeping the minimum average number of keys to be updated for each member and maintaining minimum average tree height for each member. We also propose to combine MRT and subgrouping to generate multiple MRTs such that the rekeying costs can be further minimized when compared to that of other key management schemes.

In this paper we discuss the design of passband linear phase IIR filter banks composed of allpass sections which are structurally constrained to have low coefficient sensitivity and low roundoff noise level. The design problem is formulated as H/sub /spl infin// norm minimization which is subsequently converted to a series of linear matrix inequalities (LMI) and solved by semidefinite programming. Simulation results shown that subband filters with passband linear phase property and high stopband attenuation are obtained, and the whole filter bank has small reconstruction error.

This paper presents constrained /spl lscr/ /sub 2/ norm and L/sub /spl infin// norm optimal QMF banks designs. Both methods cast the design problems as a linear objective function minimization problem subject to linear matrix inequality (LMI) constraints, which are solved by semidefinite programming. The LMI constraints are shown to be convex. Consequently, the designed QMF banks are globally optimal with respect to the objective function.

This paper investigates a novel active buffer management scheme, "jitter detection" (JD) for gateway-based congestion control to stream multimedia traffics in packet-switched networks. The proposed active buffer management scheme will improve the quality of service in multimedia networking by detecting and discarding useless packets that accumulated large enough jitter. Such as to maintain a high bandwidth for packets within the multimedia stream's jitter tolerance. Simulation results have shown that the proposed scheme can effectively lower the average packet jitter and increase the goodput of the received packets when compared to random early detection (RED), and droptail used in gateway-based congestion control. Furthermore, simulation results have also revealed that the proposed scheme can maintain the same TCP-friendliness when compared to that of RED and droptail used for multimedia streams.

A systematic method for designing minimal mean square error (MMSE) FIR equalizer for shorten length trailing zero (TZ) precoder is proposed in this paper. The TZ precoder considered here based on nonmaximally decimated filterbank allows the number of inserted zeros to be as less as one zero per block of transmitted symbols for an arbitrary channel order. This overrides the minimal redundancy insertion constraint in traditional TZ precoding system, such that the proposed equalizer can maximize the channel throughput by minimizing the inserted redundancy. A systematic method for parameterizing the solution of ZF equalizer is derived. The parameterized solution is useful for analyzing and computing the optimal ZF equalizer with a given optimization criteria. Simulation results are presented to illustrate the advantages of the MMSE equalizers obtained by the proposed design method.

Time-domain equalizers (TEQs) have been applied extensively to shorten the channel impulse response, thus enhancing the transmission efficiency of multitone and multicarrier systems with cyclic prefix. Recent developments on TEQs have mainly been focused on minimizing the additive noise power, minimizing the ISI power or maximizing the total throughput. This paper takes a different approach by minimizing the detection error or bit error rate (BER) using the Chernoff bound, under a fixed ISI power of the equalized channel, simulation results showed that this approach achieves better performance in terms of the bit error rate when compared to the aforementioned approaches and is robust to channel noise and channel length. Both numerical and analytical solutions have been derived.

A systematic method for designing FIR zero-forcing equalizer (ZFE) of space-time modulated coded (STMC) system based on non-maximally decimated filterbank is proposed. The physical channel considered is assumed to be MIMO with intersymbol interference (ISI) and span-time correlated noise. STMC is a space-time block code (STBC). Most of the STBC system required a Iong guard period to avoid inter-block interference but, with our designed equalizer, the guard period is not always necessary This can greatly enhance the spectral efficient of STMC especially when the channel dispersion is large. In our derivation, we first proposed some existence condition for the FIR ZFE of STMC. These include the maximal code rate STMC for given channel and the minimal required filter order. A verification method for the equalizability of given STMC precoder is also proposed. After that a parameterized solution of FIR ZFE of STMC is derived. Base on this parameterized result, the optimal FIR ZFE is obtained. By observing these results, we found that FIR ZFE can he further improved by adding a simple permutation in the system.

This paper discusses the design of prototype filter for cosine modulated filter banks. In particular we present a design method to design a prototype filter for DC-leakage free cosine modulated filter banks. The design problem is first formulated as quadratic constrained least square optimization problem. The quadratic constraints are linearized by means of an iterative least-square algorithm that updates the prototype filter using the least-square result obtained in the previous iteration. Simulation results have shown that the proposed design method converges within a few iterations, and high performance cosine modulated filter banks that have large stopband attenuations are obtained with various design specifications for both traditional cosine modulated filter banks and DC-leakage free cosine modulated filter banks.

A systematic method to design a power optimized FIR precoder for a special class of ISI free noise robust precoder-equalizer structure is presented in this paper. The proposed equalizer has the lowest implementation complexity in theory, because the equalizer consists of a simple sampler only. It is also because of this simple equalizer, the proposed precoder-equalizer pair is robust to channel noise. The presented design method results in a minimal power precoder with a given order such that the system achieve ISI free MMSE communication in ISI additive color noise channel with a given SNR. Simulation results are presented to illustrate the performance of the proposed precoder-equalizer structure and compared it with that of the general linear precoder structure.

A multimedia-on-demand system provides real-time playback of multimedia data transferred over UDP on IP is presented. The data buffer is allocated to overcome multimedia dropout problems. A bitrate adaptive flow control system is presented which constantly maintains the buffers at or near a predefined capacity. Other system maintenance protocols are incorporated to minimize the effect of packets lost in bursty channels and nonuniform packet arrival. Simulation results are presented to demonstrate the efficiency of the developed system.

A systematic method to design power optimized FIR precoder for a special class of ISI free noise robust precoder-equalizer structure is presented in this paper. The proposed equalizer has the lowest implementation complexity in theory, because the equalizer consists of a simple sampler only. It is also because of this simple equalizer, the proposed precoder-equalizer pair is robust to channel noise. The presented design method results in minimal power precoder with a given order such that the system achieve ISI free MMSE communication in ISI AWGN channel with a given SNR. Simulation results are presented to illustrate the performance of the proposed precoder-equalizer structure and compared it with that of the general linear precoder structure.

This paper develops a blind equalization method using the zero-forcing algorithm for multiple FIR channels. The FIR channel can be identified from the second order statistics of the received signal. A zero-forcing equalizer can be constructed from the estimated channel response. To enhance the robustness of the equalizer, the zero-forcing equalizer is formulated to minimize the H/sub /spl infin// norm of the reconstruction error due to additive white noise.

The design of perfect reconstruction FIR multifilters is discussed in this paper. The Schur algorithm is applied to factorize the polyphase matrix of multifilters into lattice blocks. The multifilters are characterized by the chain parameters in each lattice block. The complete parameterization of paraunitary multifilters and a class of biorthogonal multifilters are derived. The parameterizations are minimal and result in simple design methods using unconstrained optimization.

A new class of wavelet filters, shift-invariant wavelet filters, is proposed for the purpose of image coding. The existing approaches obtain shift-invariant wavelet transform by finding the path in the full decomposition tree that minimizes the shift-variance with respect to a given cost function. This procedure is signal dependent and is inefficient for image coding, since the subband decomposition has to be performed for all shifts of input image during processing time. The shift-invariant wavelet transform proposed has a better shift-invariant property compared with the conventional dyadic wavelet transform without changing the dyadic structure. It is also independent of the input images. Experimental results in image coding show that the shift-invariant wavelet transform has a better energy compaction property. Two bit-allocation schemes, which are suitable for the proposed shift-invariant wavelet transform coding, are proposed and evaluated.

A vector valued /spl Sigma//spl Delta/ modulator is proposed for multi-input signal applications, such as color imaging. Traditional /spl Sigma//spl Delta/ modulators can be modeled with a vector quantizer in 1-D signal space. The proposed /spl Sigma//spl Delta/ modulator extends this concept to M-D vector space. An optimal noise shaping filter for the oversampled vector-valued /spl Sigma//spl Delta/ modulator is considered. Simulation results verified the improvement provided by the proposed modulator.

Discrete coefficient filter banks reduce the computational complexity for subband image coding systems. A new time domain formulation is proposed for the design of near-perfect reconstruction filter banks with discrete coefficients. It can be shown that the proposed design method yields an l/sup 2/ optimal solution which is considered to be practical in image coding applications. In addition, special emphasis is placed in designing filter banks with nonnegative scaling functions that smoothly decay to zero at block edges in order to reduce basis related artifacts. As a result, the reconstructed image does not suffer from blocking and ringing artifacts at medium bit rate (25:1 compression at 0.32 bit per pixel.).