An efficient rate–distortion optimization method for dependent view in MV-HEVC based on inter-view dependency

Rate–distortion optimization (RDO) is utilized to select the optimal coding parameters in multi-view video coding (MVC), which employs a Lagrange multiplier to balance the relationship between the distortion and the bitrate. In this paper, an efficient RDO method for the dependent view (DV) in multi-view video (MVV) is proposed based on inter-view dependency. First of all, by investigating the sources of the distortion in the DV, a new distortion model for the DV is established. In addition, based on the proposed distortion model, an efficient Lagrangian multiplier decision for B frame is proposed by considering the inter-view dependency. Finally, the optimized Lagrangian multiplier for P frame is designed using the scaling factor which is deduced to have a linear relationship with the disparity between I frame and P frame. Experiment results demonstrate that compared with the original HTM-16.0 encoder, the proposed overall method reduces 12.19% BD-rate for the DV on average, bringing 0.40 dB BD-PSNR gain.     

A novel scheme to suppress the third-order intermodulation distortion based on dual-parallel Mach–Zehnder modulator

A scheme to enlarge the spurious free dynamic range (SFDR) of the microwave photonic link is proposed based on a dual-parallel Mach–Zehnder modulator (DPMZM). By properly adjusting the phase of the RF signals and the bias voltages of the DPMZM, the second-order spurious components in the optical carrier band (OCB) of the two sub-MZMs can be canceled out completely, and the third-order and fifth-order spurious components in the first-order upper sideband (1-USB) produced by one sub-MZM have equal amplitude but \(180{^{\circ }}\) phase difference with the other sub-MZM. Therefore, as the two optical beams are combined at the output of the DPMZM and the OCB and the 1-USB are abstracted by a bandpass filter to generate the transmitted signal, all the major optical spurious components that contribute to the third-order intermodulation distortion (IMD3) are canceled out. Theoretical analysis and simulation results show that the proposed scheme, without digital linearization and other optical processor, can suppress IMD3 approximately 30 dB and improve the SFDR by \(18~\hbox {dB}\,\hbox {Hz}^{2/3}\) compared with the conventional quadrature biased MZM system.     

Novel rate control scheme for intra frame video coding with exponential rate–distortion model on H.264/AVC

Rate control regulates the output bit rate of a video encoder in order to obtain optimum visual quality within the available network bandwidth and to maintain buffer fullness within a specified tolerance range. Due to the benefits of intra-only encoding, such as less computational cost and less latency, it has been more and more widely used. In this paper, we propose an accurate intra-only rate control scheme for H.264/AVC, which includes a novel complexity measurement and a new rate–distortion (R–D) model. We also propose a linear rate–complexity model which takes the intercept into consideration to reduce the estimation error. The proposed R–D model is integrated by the linear rate–complexity model and an exponential rate–quantization model. Based on theoretical analysis and experimental validation, the proposed scheme has high bits prediction precision, and it can also accurately handle buffer fullness. Compared with JVT-W042, our algorithm achieves higher average PSNR and improves the coding quality up to 0.35 dB.     

A new fast motion estimation algorithm based on the loop–epipolar constraint for multiview video coding

There lie geometric constraints between neighboring frames in multiview video sequences. The geometric constraints are valuable for reducing spatial and temporal redundancy in multiview video coding (MVC). In this paper, we propose a new fast motion estimation algorithm based on the loop–epipolar constraint which combines loop and epipolar constraints. A practical search technique is designed according to the characteristics of the loop–epipolar constraint. Experimental results show that the proposed algorithm is efficient for sequences under different multiview camera setups.     

Circular array design based on Bayesian Cramer–Rao bound

Multidimensional Systems and Signal Processing - In this paper, we consider circular array design in the presence of a far-field or a near-field signal source. The location of the source is...     

Resource optimization in distributed cooperative multi-relay system based on STBC-OFDM

On the basis of the amplify-and-forward relaying mode, a two-hop distributed cooperative multi-relay system is proposed combining with the space-time block coding OFDM (STBC-OFDM) technique. Taking the maximum end-to-end data rate as optimization criterion, the signal-to-noise ratio (SNR) of receiving terminal is deduced. On the basis of the water-filling theory, the optimal power allocation (OPA) is achieved for each subcarrier in each antenna and each relay node (RN) of the two-hop, to realize the resource optimization. Monte Carlo method is adopted in simulation. The simulation results show that compared with the uniform resource allocation scheme, the proposed OPA strategy can improve the system capacity. And the energy consumption of each transmission bit will be decreased, indicating the improvement of resource efficiency. In the scenario that the total power is limited, the system performance can be enhanced further by the distributed cooperative multi-relay through the diversity gain.     

Optical flow estimation based on the structure–texture image decomposition

Optical flow approaches for motion estimation calculate vector fields which determine the apparent velocities of objects in time-varying image sequences. Image motion estimation is a fundamental issue in low-level vision and is used in many applications in image sequence processing, such as robot navigation, object tracking, image coding and structure reconstruction. The accuracy of optical flow estimation algorithms has been improving steadily as evidenced by results on the Middlebury optical flow benchmark. Actually, several methods are used to estimate the optical flow, but a good compromise between computational cost and accuracy is hard to achieve. This work presents a combined local–global total variation approach with structure–texture image decomposition. The combination is used to control the propagation phenomena and to gain robustness against illumination changes, influence of noise on the results and sensitivity to outliers. The resulted method is able to compute larger displacements in a reasonable time.     

Performance analysis of a rate adaptive multi-band ultra-wideband system based on quadrature fractal modulation scheme

1 Introduction Wornell and Oppenheim[1,2] first proposed a modulation technique as an interesting potential application of dy-homogeneous signals. Due to the fractal properties of the homogeneous signals, this technique is called fractal modulation afterwards. This class of homogeneous signals remains invariant under scaling of the time axis. Dy-homogeneous signals satisfy the dyadic self-similarity property[3] s (t ) = 2 kH s (2 kt) (1) For all integers k and a constant H, termed the degree…     

Mitigation of channel estimation error in TR–UWB system based on a novel MMSE equalizer

The time reversal (TR) technique combined with the ultra-wideband (UWB) system offers a new potential for decreasing the cost and complexity of the UWB receivers. In spite of TR–UWB's good performance in perfect channel state information (CSI), it is very sensitive to the channel estimation error. The effect of channel imperfection on the TR–UWB system is considered in this paper. At first, based on a minimum mean square error (MMSE) equalizer receiver, a prefilter is calculated in closed form to improve the performance of the TR–UWB system in an imperfect CSI scenario. Furthermore, for comparison purposes, a similar calculation for prefilter is carried out based on a simple matched filter (MF) receiver. Then, in order to improve the MF receiver performance, a two-stage iteration-based algorithm is developed. The initial value for this iteration-based improved algorithm is considered to be a prefilter which is calculated in the TR–UWB system with MMSE equalizer. This optimized algorithm causes the channel estimation error in the TR–UWB system to become zero in some steps. Finally, exhaustive simulations are done to demonstrate the performance advantage attained by the improved algorithm.     

Visible–infrared person re-identification based on key-point feature extraction and optimization

Feature extraction for visible–infrared person re-identification (VI-ReID) is challenging because of the cross-modality discrepancy in the images taken by different spectral cameras. Most of the existing VI-ReID methods often ignore the potential relationship between features. In this paper, we intend to transform low-order person features into high-order graph features, and make full use of the hidden information between person features. Therefore, we propose a multi-hop attention graph convolution network (MAGC) to extract robust person joint feature information using residual attention mechanism while reducing the impact of environmental noise. The transfer of higher order graph features within MAGC enables the network to learn the hidden relationship between features. We also introduce the self-attention semantic perception layer (SSPL) which can adaptively select more discriminant features to further promote the transmission of useful information. The experiments on VI-ReID datasets demonstrate its effectiveness.     

Fuzzy control of dc–dc converters based on user friendly design

The aim of this paper is to show how to build a fuzzy controller and its membership functions automatically. In a fuzzy logic controller (FLC), the proposed method allows one easily to construct a set of membership functions, called shrinking-span membership functions (SSMFs). The FLC uses Mamdani-type fuzzy controllers for the defuzzification strategy and inference operators. The FLC hardware implementation is performed on an 8-bit microcontroller. Simulation results and experimental results demonstrate that the converter can be regulated with good performance even when subjected to input disturbance and load variation. The presented approach is generally valid for the design of an FLC, and can be applied to any dc–dc converter topologies.     

Direction-of-arrival estimation based on spatial–temporal statistics without knowing the source number

Direction-of-arrival (DOA) estimation is a central problem in array processing and has a variety of applications. In this paper, a new algorithm for finding DOAs of multiple temporally correlated signals is devised. The proposed approach is based on the joint diagonalization structure of a set of spatio-temporal correlation matrices. Unlike the subspace-based DOA estimators, it is not necessary to estimate the noise or signal subspace explicitly. Moreover, the proposed method can provide the spatial spectrum and estimate the DOAs even when the number of sources is not known a priori. Interestingly, it is revealed that the well-known MUSIC method is a special case of our algorithm. Simulation results validate that the developed approach is superior to conventional DOA estimators in terms of resolution capability, estimation accuracy, and robustness against array model errors.     

New fractional-order LADRC scheme based on a novel filtered-Bode’s ideal transfer function for integer-order systems

In this paper, a new Fractional-Order Linear Active Disturbance Rejection Control scheme (FO-LADRC) is proposed to enhance the robustness against loop gain variations of the standard Active Disturbance Rejection Control (ADRC) in the case of uncertain integer-order systems. A new filtered Bode’s ideal transfer function (F-BITF) is proposed to be used as a reference model in the design approach of the proposed control scheme to ensure the dynamic behavior of the closed-loop BITF to the controlled system. A Fractional-order Extended State Observer (F-ESO) is used in the proposed FO-LADRC structure to approximate the system to be controlled by a filtered fractional-order integrator. The fractional order of the F-ESO is a design parameter to tune to achieve the desired overshoot of the closed-loop step response. For the tuning of FO-LADRC structure, an analytical method is proposed. The performance of the proposed FO-LADRC and the Chen’s et al. FO-ADRC structures are evaluated thorough numerical simulation, and then validated in practice in the case of a Cart-Pendulum. Both the simulation and the experimental results show that the proposed FO-LADRC is able to achieve the desired dynamics of the F-BITF and guarantee the robustness with respect to the controller gain variation and the system parameter uncertainties. The comparative study conducted also reveals that the proposed control scheme is more robust than that of Chen.     

Quality measure of color images based on properties ofvision psychology and color distortion in MPEG-21

In this article, a new way to evaluate the quality of color images is proposed, in which the properties of human vision psychology, objective fidelity, edge information, and color distortion will be combined through utilizing 3-D matrix transform. There exists color redundancy and structural similarity between three different frames of a color image, the definition of vision properties will be measured by 3-D submatrix integration transform (SIT), in which three color components are integrated into one model and color redundancy can be exploited fully. The simulation results show that the measure index is very effective and objective in accord with vision properties.     

Visual saliency’s modulatory effect on just noticeable distortion profile and its application in image watermarking

Perceptual watermarking should take full advantage of the results from human visual system (HVS) studies. Just noticeable distortion (JND) gives us a way to model the HVS accurately. In this paper, another very important aspect affecting human perception, visual saliency, is introduced to modulate JND model. Based on the visual saliency’s modulatory effect on JND model which incorporates visual attention’s influence on visual sensitivity, the saliency modulated JND profile guided image watermarking scheme is proposed. The saliency modulated JND profile guided watermarking scheme, where the visual sensitivity model combined with visual saliency’s modulatory effect is fully used to determine image-dependent upper bounds on watermark insertion, allows us to provide the maximum strength transparent watermark. Experimental results confirm the improved performance of our saliency modulated JND profile guided watermarking scheme in terms of transparency and robustness. Our watermarking scheme is capable of shaping lower injected-watermark energy onto more sensitive regions and higher energy onto the less perceptually significant regions in the image, which yields better visual quality of the watermarked image. At the same time, the proposed saliency modulated JND profile guided image watermarking scheme is more robust compared to unmodulated JND profile guided image watermarking scheme.     

Resource allocation based on cross-layer QoS-guaranteed scheduling for multi-service multi-user MIMO–OFDMA systems

Cross-layer strategies for resource allocation in wireless networks are essential to guaranty an efficient utilization of the scarce resource. In this paper, we present an efficient radio resource allocation scheme based on PHY/MAC cross layer design and QoS-guaranteed scheduling for multi-user (MU), multi-service (MS), multi-input multi-output (MIMO) concept, orthogonal frequency division multiple access (OFDMA) systems. It is about a downlink multimedia transmission chain in which the available resources as power and bandwidth, are dynamically allocated according to the system parameters. Among these parameters, we can mention the physical link elements such as channel state information, spectral efficiency and error code corrector rate, and MAC link variables, which correspond to the users QoS requirements and the queue status. Primarily, we use a jointly method which parametrizes these system parameters, according to the total power, and the bit error rate constraints. Secondly, we propose a QoS-guaranteed scheduling that shares the sub-carriers to the users. These users request several type of traffic under throughput threshold constraints. The main objective in this work is to adjust the average throughput per service of each user, according to their needs and likewise to satisfy a great number of connexions. Subsequently, we consider a model of moderated compartmentalization between various classes of services by partitioning the total bandwidth into several parts. Each class of service will occupy a part of the bandwidth and will be transmitted over a maximum number of sub-carriers. The simulation results show that the proposed strategy provides a more interesting performance improvement (in terms of average data rate and user satisfaction) than other existing resource allocation schemes, such as nonadaptive resource allocation strategy. The performances are also analyzed and compared for the two multi-service multi-user MIMO–OFDMA systems; with sub-carriers partitioning and without sub-carriers partitioning.     

A new authentication based cheating prevention scheme in Naor–Shamir’s visual cryptography

Visual cryptography (VC), first presented by Naor and Shamir, is a variant of secret sharing, thus it also called visual secret sharing. It can be widely used in many applications such as encrypting large data efficiently. In the literature, the problem of cheating is under consideration in secret sharing. Recently, Horng et al. pointed out that cheating is possible in k-out-of-n VC schemes, and presented two kinds of the cheating prevention schemes for protecting honest participants. One of them is the authentication based cheating prevention scheme. In this paper, we analyze the definition of cheating prevention and propose a new authentication based cheating prevention scheme. This scheme is constructed with Naor–Shamir’s VC scheme. Finally, we give the security analysis to prove that the proposed scheme is immune to cheating.     

Tartaglia–Pascal triangle and Brownian motion in non-euclidean geometries: application to heat and Black–Scholes equations

The recent worldwide explosion of the financial market originating also from the Black–Scholes equation proved how fundamental could be Brownian motion to real life. Brownian motion is deeply rooted into discrete spaces that are well represented by a Tartaglia–Pascal triangle (TPt). Furthermore, this mapping can be extended to the case of the Schrödinger equation: one of the key equations of quantum mechanics. The connection arises from the asymptotic formula for the binomial coefficients and the normal probability density function. This paper shows how this mapping between the discrete spaces, represented through some forms of TPt, extends to Brownian motion in different geometries. One of the well-known cases is the heat equation; another one is the Black–Scholes equation that derives from geometric Brownian motion. It is shown that the TPt becomes a periodic structure for the Brownian motion on a circle. For the geometric Brownian motion, we get a scale deformed TPt the main effect being scale deformations into the corresponding Newton binomial formula. In the asymptotic limit, one recovers the known formula for the sum on a row of the TPt. This approach unveils discrete structures underlying Brownian motion on different geometries revealing a possible conjecture that, for a given stochastic motion, it is always possible to associate a discrete map such that a TPt is obtained. In a general case, outcomes of the elements of the triangle become real numbers.