Riccardo Bernardini

University of Udine | UNIUD · Department of Electrical, Management and Mechanical Engineering

Communications from deep space need to overcome two major issues: the strong attenuation due to the large distances and the limited power available at the transmitter. A class of sensors which looks promising for deep space communications is provided by the superconducting nanowire single-photon detectors that are characterized by very small jitter...

When designing a car, the vehicle dynamics and handling are important aspects, as they can satisfy a purpose in professional racing, as well as contributing to driving pleasure and safety, real and perceived, in regular drivers. In this paper, we focus on the assessment of the emotional response in drivers while they are driving on a track with dif...

Many problems in signal processing [e.g., filter bank design, independent component analysis (ICA), beamforming design, and neural network training] can be formulated as optimization over groups of transformations that depend continuously on real parameters (Lie groups). Such problems are usually tackled in two ways: using a constrained optimizatio...

Background Nowadays research on Autonomous Driving Systems (ADS) and attention towards novel technology allowing real-time assessment of car drivers' psycho-physiological status is growing, to quantify driver's stress during semi-autonomous or autonomous driving assistance and to investigate human reaction to different types of ADS. We present a sy...

Physically Obfuscated Keys (POK) are used to embed in chips secret bit-strings to be used in cryptographic protocols. Usually a POK is built as an array of elementary 1-bit POKs (cells). In order to guarantee that the same secret bit-string is generated at every turn-on, stabilizer circuits are required, which are typically based on possibly expens...

The evaluation of car drivers’ stress condition is gaining interest as research on Autonomous Driving Systems (ADS) progresses. The analysis of the stress response can be used to assess the acceptability of ADS and to compare the driving styles of different autonomous drive algorithms. In this contribution, we present a system based on the analysis...

Objective: in this paper we propose a system to detect a subject's sympathetic reaction, which is related to unexpected or challenging events during a car drive. Methods: we use the Electrocardiogram (ECG) signal and the Skin Potential Response (SPR) signal, which has several advantages with respect to other Electrodermal (EDA) signals. We recor...

We present a system where a simple and low-complexity classification algorithm is used to identify the stress of a person while driving a car, using EDA Skin Potential Response (SPR) measurements. An adaptive filter, which takes the steering wheel signal as a reference signal, is used to remove the motion artifacts that appear in the recorded SPR s...

In this paper we propose the application of supervised learning techniques to recognize stress situations in drivers by analyzing their Skin Potential Response (SPR) and the Electrocardiogram (ECG). A sensing device is used to acquire the SPR from both hands of the drivers, and the ECG from their chest. We also consider a motion artifact removal al...

Differential equations are commonplace in engineering, and lots of research have been carried out in developing methods, both efficient and precise, for their numerical solution. Nowadays the numerical practitioner can rely on a wide range of tools for solving differential equations: finite difference methods, finite element methods, meshless, and...

The problem of automatic detection of car drivers’ stress levels has become increasingly important, due to its impact on people security, and more generally on people health and well-being. Among the various techniques proposed for stress detection, Electrodermal Activity (EDA) monitoring is particularly interesting to gain information about the in...

The problem of generating a sequence of true random bits (suitable for cryptographic applications) from random discrete or analog sources is considered. A generalized version, including vector quantization, of the classical approach by Elias for the generation of truly random bits is introduced, and its performance is analyzed, both in the finite c...

Objective: Compressive Sensing (CS) has recently been applied as a low complexity compression framework for long-term monitoring of electrocardiogram signals using Wireless Body Sensor Networks. Long-term recording of ECG signals can be useful for diagnostic purposes and to monitor the evolution of several widespread diseases. In particular, beat...

Objective: Compressive Sensing (CS) approaches to electrocardiogram (ECG) analysis provide efficient methods for real time encoding of cardiac activity. In doing so, it is important to assess the downstream effect of the compression on any signal processing and classification algorithms. CS is particularly suitable for low power wearable devices,...

The recent availability of reliable schemes for physically unclonable constants (PUC) opens interesting possibilities in the field of security. In this paper, we explore the possibility of using PUCs to embed in a chip random permutations to be used, for example, as building blocks in cryptographic constructions such as sponge functions, substituti...

Physically Unclonable Constants (PUC) are circuits used to embed unique secret bit-words in chips. We propose a simple PUC, employing two Schottkydiodes in reverse. The difference of the reverse currents of the two diodes is used to charge a capacitance. The charge stops when the two currents become equal. It is shown that this scheme has a single...

This manuscript addresses the problem of non-invasive fetal Electrocardiogram (ECG) signal acquisition with low power/low complexity sensors. A sensor architecture using the Compressive Sensing (CS) paradigm is compared to a standard compression scheme using wavelets in terms of energy consumption vs. reconstruction quality, and, more importantly,...

Physically Unclonable Constants (PUC) are circuits used to embed unique secret bit-words in chips. We propose a simple PUC, with a complexity comparable with an SRAM cell. The proposed scheme is studied both theoretically and by means of simulations and it is shown that the proposed PUC is both unbiased and very stable. In particular, its intra-dis...

In this work, we consider the problem of detection of fetal heart beats from abdominal, non-invasive mixture recordings. We propose a new method for the separation of maternal and fetal beats based on the sparse decomposition in an over-complete dictionary of Gaussian-like functions. To increase the detection capability, we also use Independent Com...

Objective: Analysis of fetal electrocardiogram (f- ECG) waveforms, as well as fetal heart-rate (fHR) evaluation, provide important information about the condition of the fetus during pregnancy. A continuous monitoring of f-ECG, for example using the technologies already applied for adults ECG tele-monitoring (e.g., Wireless Body Sensor Networks, W...

Physically Unclonable Constants (PUCs) have recently been proposed for private ID generation. Since in most of the proposed PUC schemes the generated value is not stable (i.e., it can change at different turn-ons), a post-processing with a stabilizer is usually required. Most of the proposed stabilizer schemes use auxiliary data (helper data) to ov...

We propose a four-MOSFET circuit for unbiased 1-bit Physically Unclonable Constant (PUC), that is, a Physically Unclonable Function with no input. The proposed scheme is a very good approximation of the ideal PUC, while having the complexity of an SRAM cell. The reliability of our solution is close to ideal and it is stable over a wide range of tem...

Compressive Sensing (CS) is a newly introduced signal processing technique that enables to recover sparse signals from fewer samples than the Shannon sampling theorem would typically require. It is based on the assumption that, for a sparse signal, a small collection of linear measurements contains enough information to allow its reconstruction. Co...

In this paper we define the new concept of a perfectly reliable encoder (PRE) for erasure channels as an encoder whose performance is optimal for every value of the loss probability. As a first step toward the design of such an encoder, we propose an idealized extreme unequal error protection encoding scheme. We derive models to optimize the encode...

Physically Unclonable Functions (PUFs) have been recently proposed as a way to include, in chips, functions that can act as “fingerprints” of the chip, to be used in applications like chip authentication (strong PUF) or private ID generation (weak PUF). Most of the schemes proposed for weak PUF exploit helper data to make the PUF more reliable. The...

We consider the problem of true random bit generation from source vectors of independent geometric random variables, reduced modulo M for practical implementation. Independent geometric random variables result from measurements of discretized Poisson processes, which are good models for a number of physical sources. We propose a generalization of t...

Most of latest-generation multimedia systems are equipped with increasingly-effective object detection algorithms (e.g., intelligent video surveillance systems, augmented reality applications, sharing platforms for multimedia data, etc.). Unfortunately, images and video are usually available in compressed formats, which makes object detection more...

Rate control for multimedia streaming has been the subject of many recent research activities and is crucial for peer-to-peer networks, where controlling the rate at the source is ineffective. In this paper we propose a two-stage procedure for rate control. In particular, the first stage, based on Integer Linear Programming and a distortion model,...

A method for Peer-to-Peer streaming of Video-on-Demand with residential nodes is described. A possible problem with doing peer-to-peer video-on-demand streaming is the necessity of storing on the disk of the residential user the content to be streamed, allowing a malicious user to distribute illegally the content. The proposed method has the advant...

The widespread of augmented reality applications, cognitive video surveillance, autonomous or supportive navigation systems, has increased the importance of accurate object detection algorithms. However, the presence of noise depending on the characteristics of the acquisition device, on lighting intensity and directions, and on weather conditions,...

Rate control for multimedia streaming has been the subject of many recent research activities. In this paper we propose a simple, but optimal technique for rate control that does not require the knowledge of the type of the multimedia data, but only needs that every packet is labeled with a “priority value” that represents the relative importance o...

Streaming solutions based on peer-to-peer networks have recently attracted the attention of the research community, due to the fact that the possibility to exploit peers' upload bandwidth can make it possible to transmit to a large number of users at a low costs. In this paper, we analyze the packet loss probability experienced at the application l...

In this paper we propose and compare different distributed video coding (DVC) schemes based on the use of the wavelet transform, which naturally allows for spatial and other forms of scalability. In particular, we propose a hybrid encoder which utilizes channel codes, and evaluate its performance in the absence of a feedback channel. The proposed s...

Some peer-to-peer streaming systems make use of linear codes to reduce the rate of the data uploaded by peers with limited upload capabilities. Such “data reduction” techniques are based on a vector-space approach and produce the data to be uploaded by means of linear combinations of the content data in a suitable finite field. In this paper, we pr...

Video transmission over IP is currently a hot topic both in entertainment and research communities. A problem that threatens the development of video over IP services is the bandwidth required to serve a potentially very large number of users. In this context, Peer-to-peer (P2P) technologies are considered a possible solution for the distribution o...

In this paper we analyze the jitter experienced by a node that re-ceives data streamed over a peer-to-peer network that employs net-work coding procedures. In the considered scheme, a node can reconstruct a packet as soon as it receives the first fastest K packets of a set of N > K packets. We propose a model of the overall de-lay experienced by th...

In this paper, we propose a procedure to recover lost slices in inter-coded H.264/AVC video frames. The procedure recovers missing pixels by exploiting temporal information. In particular, it considers 4 × 4 blocks and performs a full search procedure on an adaptive size window in the reference frames, in order to determine the best block according...

In this paper, we consider the problem of processing finite-length signals by means of critically sampled or oversampled filter banks. Based on a polyphase matrix factorization of the filter bank, we propose a realization adaptation that does not make any assumption about the signal values outside the support of the input signal, contrary to what i...

The growing applications of image and image-sequence processing call for the computation of the discrete Fourier transform (DFT) of multidimensional signals defined on lattices of general type. The multidimensional DFT formula, introduced by Mersereau, allows one to choose the frequency domain sampling lattice, which is not univocally determinated...

Tensor analysis plays an important role in modern image and vision computing problems. Most of the existing tensor analysis approaches are based on the Frobenius norm, which makes them sensitive to outliers. In this paper, we propose L1-norm-based tensor ...

In this paper, we propose a procedure to recover lost slices in intra-coded H.264/AVC video frames. The procedure recovers missing pixels by exploiting only the video frame spatial redundancy, with no reference to past frames. This situation is interesting in correspondence to scene changes. The proposed scheme determines the presence of a dominant...

Video match analysis is used for the assessment of physical performances of professional soccer players, particularly for the identification of "high intensities" considered as "high running speeds." However, accelerations are also essential elements setting metabolic loads, even when speed is low. We propose a more detailed assessment of soccer pl...

Scalable video coding (SVC) was recently standardized as an extension of the H.264/AVC standard. A scalable coder allows to combine different layers of spatial, temporal and quality scalability, and is a viable solution for adaptation to user characteristics and network conditions. On the other hand, Multiple description coding (MDC) can provide er...

The paper presents two cross-layer optimization strategies based on the IEEE 802.11e standard that enable a robust video transmission using adaptively forward error correction (FEC) channel codes at transport layer and a multiple description coding (MDC) architecture. The first approach estimates an array of correlation measures for the group of pi...

This paper presents two cross-layer optimisation strategies based on the IEEE 802.11e standard that enable a robust video transmission using adaptively Forward Error Correction channel codes at transport layer and a Multiple Description Coding architecture. The first approach classifies the characteristics of the sequence to be coded, while the sec...

Hilbert space frames have recently attracted attention in the signal processing community. In this paper, we consider the problem of describing the statistical distribution of the error amplification and lower bound of a frame obtained by randomly picking vectors from a larger frame (the frame pool ). The key result of this paper is an analytic bou...

This paper proposes an error resilient coding scheme that employs distributed video coding tools. A bitstream, produced by any standard motion-compensated predictive codec (MPEG-x, H.26x), is sent over an error-prone channel. In addition, a Wyner-Ziv encoded auxiliary bitstream is sent as redundant information to serve as a forward error correction...

This paper proposes an error resilient coding scheme that employs distributed video coding tools. A bitstream, produced by any standard motion-compensated predictive codec (MPEG-x, H.26x), is sent over an error-prone channel. In addition, a Wyner–Ziv encoded auxiliary bitstream is sent as redundant information to serve as a forward error correction...

In this paper we propose a chunkless structure for multimedia distribution over peer-to-peer networks. With the proposed approach, the original multimedia packets are partitioned into several reduced packets whose transmission requires a fraction 1/R of the bandwidth required by the original data. The generation of the reduced packets depends on a...

Distributed video coding (DVC) has recently been proposed for emerging scenarios, where sources of correlated video do not communicate, as in some video-surveillance applications, or to simplify the coder for video equipment with power consumption constraints. In this paper we propose and compare different DVC schemes. In particular, we propose the...

The robust transmission of video sequences over wireless LANs presents several challenging problems concerning the presence of packet losses, delays, and bandwidth limitations. Their effect on the visual quality of the sequence reconstructed by the end user can be mitigated by adopting a wireless architecture that is able to support different level...

Unit-norm tight frames (UNTFs) are interesting in the context of robust transmission because of their robustness to erasures. In this correspondence, we show how to convert any finite-dimensional UNTF into an oversampled filter bank which implements a UNTF. The proposed construction uses the vectors of the finite-dimensional frame as modulating fun...

In this paper, we consider the construction of time-varying, support-adapted, oversampled filter banks. In particular, we consider a general class of filter banks, which includes tight frames and orthogonal filter banks as special cases. We show that it is possible to construct a set of boundary filters, which allows the application of the filter b...

In this paper we consider an error resilience scheme, based on a Distributed Video Coding (DVC) paradigm, for the transmission of coded video over an error prone channel. In the proposed scheme, an auxiliary stream which contains generalized parity bits is generated for each coded frame. At the decoder side, error concealed decoded frames are used...

We consider the problem of robust video streaming over networks that support QoS differentiation, such as the 802.11e wireless network infrastructure. We consider the benefits obtained matching the H.264 data partitioning (DP) mode with such a QoS-based interface. We compare this solution with an innovative scheme which combines a multiple descript...

In this paper, we propose a frame-based multiple description video coder. The analysis filterbank is the extension of an orthogonal filterbank which computes the spatial polyphase components of the original video frames. The output of the filterbank is a set of video sequences which can be compressed with a standard coder. The filterbank design is...

In this paper we present a wavelet domain distributed coder for video which allows for scalability and does not require any feedback channel. Efficient distributed coding is obtained by processing the wavelet transform with a suitable "folding" function and compressing the folded coefficients with a wavelet coder. At the receiver side, we use the s...

Oversampled filter banks are currently being proposed for robust transmission applications. In this paper, we completely characterize multidimensional doubly finite-impulse-response (FIR) filter banks, that is, oversampled filter banks whose dual is FIR. Then, we consider the problem of extending perfect reconstruction critically sampled multidimen...

This paper analyzes the problem of error amplification in frame-based coding schemes derived from oversampled filter banks. Oversampled filter banks are currently being proposed for robust transmission applications, since added redundancy can be used for error recovery in case of losses. Error amplification is determined by the lower bound of the s...

Summary form only given. We propose an innovative scheme for distributed coding of two correlated variables X and Y. After analyzing the proposed scheme in some detail, we compare it with joint coding via Karhunen-Loeve transform followed by uniform quantization and entropy coding. We carried out some experiments with X = Y + N, where X, Y and W ar...

In this paper we propose a general distributed coding technique for an N-source scenario with low computational requirements at the coder side. The key hypothesis is that it must be possible to find an approximate estimate of each source from the knowledge of a "reference soruce" and that the estimation error can be statistically described.

Video streaming over packet switched best-effort networks is a challenging topic, due to low latency, scalability and fault tolerance requirements. Many techniques can be used to deal with delay, loss and the time-varying nature of best-effort networks. In this paper we compare two techniques to improve the performance of video streaming, i.e., a m...

Redundant bases or frames are a promising technique for multiple description signal coding. Frames can provide sufficient redundancy for recovery in case of coefficient losses due, for instance, to packet transmission errors. In this paper, we consider the problem of dual frame computation in the context of finite impulse response (FIR) analysis an...

In this paper, we jointly consider the source and channel coding problem with transmission over power line channels. We propose frame based multiple description (MD) video coding with an efficient reconstruction algorithm. Further, transmission deploys wide-band impulse modulation with bit interleaved convolutional channel coding. The MD video code...

We propose a robust and scalable transmission scheme based on multiple description coding (MDC). Each description is encoded using a standard video codec such as MPEG-2 or H.264. This scheme provides equal or better robustness with respect to other solutions such as forward error correction (FEC), at lower system complexity; also, it provides scala...

Multiple description coding has been recently proposed for images and video transmission in packet erasure channels because of its good loss recovery capability. In this paper, we consider the problem of bit allocation and quantization optimization for frame based multiple description coding schemes obtained by means of an oversampled filterbank. W...

In this work, we propose a multiple description (MD) coding system for video streams. In particular, our scheme originates four descriptions from the spatially downsampled polyphase components of the original frames. Each description is compressed independently with the recent H264/AVC video coding standard, it is packetized and sent over an error...

Cosine-modulated filter banks (CMFB's) are filter banks whose impulse responses are obtained by modulating a window with cosines. Among their applications are video and audio compression and multitone modulation. Their continuoustime counterpart is known as local cosine bases. Even though there is an extended literature on the discrete-time case bo...

In this paper, we propose a simplified Frame based Multiple Description (MD) coding system for video streams. The proposed system uses an overdetermined filter bank to generate multiple descriptions of the original video stream, and allows for exact signal reconstruction even in the presence of packet losses. Each description is coded using the rec...

In this paper we propose a system based on Multiple Description coding (MD) to stream video over lossy or variable bandwidth networks. MD coding can be integrated in several ways into existing state-of-the-art video codecs, as MPEG or the new H.264. The proposed scheme is based on polyphase downsampling in the pixel domain, followed by independent...

Because of their interactive nature, multimedia streams must be sent over UDP and suitable countermeasures for minimizing the effect of data loss have to be taken. Among the various proposed techniques, coding with redundant filter banks has been proposed as a mean to add robustness to the data stream. In order to avoid the computationally expensiv...

In this paper we propose a system based on multiple description coding (MD) to stream video over lossy or variable bandwidth networks. MD coding can be integrated in several ways into existing state-of-the-art video codecs, as MPEG or the new H.264. The proposed scheme is based on polyphase downsampling in the pixel domain, followed by independent...

Multiple description (MD) coding has recently been recognized as an interesting option for data communication over lossy networks. Among the proposed techniques, Multiple Description using frames has received attention because of its possible advantages over error correcting codes. In frame-based MD, the input signal is analyzed with a redundant fi...

Due to their interactive nature, multimedia streams must be sent over UDP with suitable countermeasures for min-imizing the effect of data loss. Coding with oversampled filter bank is a promising multiple description technique which allows for signal reconstruction even in presence of packet loss. Although the coded signal can be recon-structed by...

This work proposes a random numbers generator for application in the field of secure communications. In order to get truly unpredictable sequences a chaotic system is used. Indeed, due to their extreme sensitivity to initial conditions, chaotic systems lend themselves to be exploited for generation of random numbers. This work explores this possibi...

The standard way of remotely visualizing virtual worlds is downloading the virtual world to the user's computer, then rendering it. This approach is plagued by many problems which can be overcome by moving the rendering at server's side and by essentially turning interactive visualization into an image transmission problem. How to effectively compr...

The construction of photo-realistic virtual worlds is at reach of current computer graphics. Unfortunately, the philosophy currently adopted for the diffusion of virtual worlds over the Internet, which calls for downloading at client side the 3D virtual world description, does not allow several user to share the same virtual world. Recently, in ord...

The construction of photo-realistic virtual worlds is at reach of current computer graphics. Unfortunately, the philosophy currently adopted for the diffusion of virtual worlds over the Internet has a fundamental drawback: it calls for downloading at client side the D virtual world description. Recently, the splitbrowser approach was proposed in or...

This work introduces a geometrical interpretation of the Chinese remainder theorem (CRT) which is novel and which can be profitably used in the field of multidimensional signal processing. The practical application of the proposed result in some multidimensional signal processing procedures is demonstrated

It is well known that the output of chaotic systems can be completely predicted from the exert knowledge of the initial conditions. However, their extreme sensitivity to initial conditions lends itself to being exploited for generation of random numbers. This work explores this possibility and gives a simple circuit arrangement, together with the t...

This work proposes a fully integrated random numbers generator. A chaotic system has been chosen as a source of randomness, in order to grant statistical independence and uniform distribution to the 8-bit generated words. An effective and compact architecture, based on a pipeline ADC only, has been singled out and realized in a standard 0.8 μm CMOS...

Chaotic modulation is a way to transmit digital information by means of chaotic signals instead of sinusoids. Currently proposed schemes, obtained from traditional transmission systems by replacing sinusoids with chaotic signals, perform poorly when compared to traditional modulation schemes. In this paper we presented an original scheme of chaotic...

Exporting methods and tools used in industrial areas, where the profits can justify high modeling costs, may only be a starting point for cultural heritage modeling, but not a sustainable solution in view of the economics of this application. A way to lower the costs is to automate the modeling procedure. This work presents a robust procedure for t...

Three-dimensional virtual environments are gaining popularity in such applications as e-commerce, virtual visits of cultural heritage and videogames. The way virtual environments are currently accessed over the Internet is plagued by two major problems: the first one is due to the fact that the user must spend a considerable amount of time to downl...

Phase correlation is a very robust technique to estimate image translations, but it works only for monochromatic images. If the input image is a color image, it must be first converted to monochrome, wasting part of the input information. In this work we extend the phase correlation algorithm to the case of multi-component images such as RGB and mu...

Volterra filters are a classical instrument for nonlinear channels and systems modeling, noise and echo cancellation, signal estimation and detection, and various other applications. As is well known, the computational weight of Volterra filters exponentially grows with the nonlinearity degree. This work presents a contribution to the efficient com...

We extend to general finite groups a well-known relation used for checking the orthogonality of a system of vectors as well as for orthogonalizing a nonorthogonal one. This, in turn, is used for designing local orthogonal bases obtained by unitary transformations of a single prototype filter. The first part of this work considers abelian groups. Th...

Image rototranslations can be estimated in the frequency domain by exploiting the fact that a rotation of the space domain maps itself into a rotation of the frequency domain. The author shows that a distortion enjoys such a property if and only if it is an affine transform

Spurious range data pose a serious visualization problem with active light systems, as they can totally deform the acquired 3-D shapes. This work presents a technique for their detection based on geometrical considerations. The proposed method does not need extra hardware and can be used effectively for the provision of post-processing noise remova...

We extend to general finite groups a well-known relation used for checking the orthogonality of a system of vectors as well as for orthogonalizing a nonorthogonal one. This in turn, is used for designing local orthogonal bases obtained by unitary transformations of a single prototype filter. The first part of this work considered the abelian groups...

Video transmission over IP is currently a hot topic both in entertainment and research communities. A problem that threatens the development of video over IP services is the bandwidth required to serve a potentially very large number of users. In this context, Peer-to-peer (P2P) technologies are considered a possible solution for the distribution o...

We show how to design filters given a prescribed tiling of the time-frequency plane. Moreover, we impose on these filters the structure of local orthogonal bases. These bases were recently constructed as a generalization of the cosine-modulated filter banks in discrete time and local trigonometric bases in continuous time. They have been found to b...

A multidimensional fast Fourier transform (FFT) algorithm is presented for signals with arbitrary symmetries and periodic on arbitrary lattices. Applications that can benefit from such an algorithm include Volterra filtering and analysis of x-ray diffraction data. The presented algorithm exploits signal redundancy to achieve a computational complex...

We show how to design filters given a prescribed tiling of the time-frequency plane. Moreover, we impose on these filters the structure of local orthogonal bases. These bases were recently constructed as a generalization of the cosine-modulated filter banks in discrete time, and local trigonometric bases in continuous time. They have been found to...

We present an overview of the work on local orthogonal bases in the past couple of years and their applications in signal processing. Local orthogonal bases can be seen as a generalization of local cosine bases both in continuous and discrete time. Their basis functions are obtained from a single prototype window and there exists a fast algorithm f...

Cosine-modulated filter banks (CMFBs) are filter banks whose impulse responses are obtained by modulating a window with cosines. Among their applications are video and audio compression and multitone modulation. Their continuous-time counterpart is known as local cosine bases. Even though there is an extended literature on the discrete-time case bo...