nils-herrmann/clean_scirepeval huggingface dataset:
A comb filter design using fractional-sample delay

In this paper, a new comb filter design method using fractional sample delay is presented. First, the specification of the comb filter design is transformed into that of fractional delay filter design. Then, conventional FIR and allpass filter design techniques are directly applied to design fractional delay filter with transformed specification. Next, we develop a constrained fractional delay filter design approach to improve the performance of the direct design method. Finally, several design examples are demonstrated to illustrate the effectiveness of this new design approach.
New Experiments and Analysis in Bragg-Diffraction Imaging

System performance is substantially enhanced by using good attenuators in the system and employing a pulsing mode of operation. Spurious image elements, due to multiple reflections of the ultrasound in the acoustic cell and due to echoes from elements in the system which are not part of the object plane being imaged, can be eliminated in this fashion. In addition, depth discrimination can be substantially improved, in agreement with theory.
Edge-preserving image decomposition based on guided upper/lower envelops

In this paper, we present an image decomposition method based on guided upper/lower envelops of the intensity signal. First, we estimate our upper/lower envelops by using a estimator guided by the gradient (edges). Second, using the guided envelops, we easily obtain the edge-preserving base layer of the intensity signal and its corresponding detail layer. In the end, we not only propose the JND-based detail boosting for image enhancement but also demonstrate our image abstraction/stylization. Experimental results show that our proposed method is promising as compared to the existing methods.
Effective image haze removal using dark channel prior and post-processing

Removing haze technique is an important and necessary procedure to avoid ill-condition visibility of human eyes. To improve the dehazing quality, a new haze-removing method is proposed in this paper. Specifically, this method can be properly applied to various dense and distribution haze images without sacrificing color naturalness by using refined Dark Channel Prior(DCP) and adding post processing. Experimental results demonstrate that the new method provides higher dehazing quality and color naturalness than other existing techniques.
Design of two-dimensional FIR eigenfilters for sampling-structure conversion

By minimizing a quadratic measure of the error in the passband and stopband, a 2-D diamond-shaped finite impulse response, (FIR) eigenfilter is designed for sampling-structure conversion. Time- and frequency-domain constraints, are easily incorporated into this method, such that the design difficulty inherent to sample-conversion filters can be effectively solved. A design example and simulation with test pictures are presented to demonstrate the effectiveness of the approach.
Fast Finite Field Orthogonal Transform without length constraint

In this paper, we propose a new family orthogonal transforms defined over finite field called the Finite Field Orthogonal Transforms (FFOT). Unlike the traditional Number Theoretic Transform (NTT) that the relationship between the transform length and the field moduli has specific constraint in order to hold the orthogonality property, the FFOT has no such constraint so that the signal word length need not be limited by the transform length. In addition, the fast algorithm implementation like radix-2 Cooley-Tukey algorithm is also realizable for the FFOT and is suitable for fast data encryption.
Limited color display for compressed video

Many display devices now allow a number of colors, called color palette, to be displayed simultaneously. Besides, images and videos in most world wide web (WWW) databases are in compressed formats. Therefore, it becomes an important issue to retrieve a suitable color palette from compressed domain in order to have fast and faithful color reproduction for these devices. In this paper, the color palette design methods for compressed videos are presented. The proposed approaches use the reduced image rather than the whole image for the color palette design to avoid the heavy computation in video decompression. Experimental results show that output image quality of proposed methods is acceptable, to human eyes. In addition, empirical results show that the proposed shifting window scheme can reduce the main problem of displaying quantized image sequences and screen flicker.
Dependent scalar quantization of color images

Many image display devices can allow only a limited number of colors, called color palette, to be simultaneously displayed. In order to have a faithful color reproduction of an image, the associated color palette must be suitably designed. This paper presents a dependent scalar quantization algorithm to design the color palette effectively. The dependent scalar quantization algorithm consists of two procedures, bit allocation and recursive binary moment preserving thresholding. The experimental results show that the dependent scalar quantization can reduce the computation complexity and its output images quality is acceptable to the human eyes. A rule of the quantization order is also deduced under the MSE criterion to obtain a dependent scalar quantizer which has as good a performance as compared with some other algorithms. In addition, an adaptive neighborhood-clustering algorithm, which searches the neighboring color indices of input pixels iteratively, is proposed to further improve the performance of the dependent scalar quantization algorithm. Finally, we introduce a color mapping method to reduce the contouring effect when the color palette size generated by the dependent scalar quantizer is small.
The fine-grained scalable video coding based on matching pursuits

Since channel capacity varies depending on the network traffic and the capacity of each reception, fine granularity scalability (FGS) of video coding has emerged over the past years as an important area in multimedia streaming applications. We propose a FGS video codec and a two-layer SNR scalable video codec. Both of these are based on matching pursuits (MP). The bit plane atom coding is presented to achieve the SNR scalable matching pursuits. We also propose a differential quadtree-based algorithm to encode atom positions efficiently. The, performance of our methods are compared with those of H.263+ and DCT-based FGS coder.
Color image watermarking using SVD

Digital watermark is an important technology for the image verification. Many authors researching on color image watermarking opine RGB color space in the spatial domain is not suitable for embedding marks. In this paper, we propose a digital color image watermarking method using Singular Value Decomposition (SVD). The whole process including embedding and extracting could be finished in RGB components in spatial domain. Simulation results show that our method is successful in resolving the rightful ownership of the watermarked image with good robustness, good imperceptibility and higher security.
Effective color interpolation in CCD color filter arrays using signal correlation

We propose an effective color filter array (CFA) interpolation method for digital still cameras (DSCs) using a simple image model that correlates the R,G,B channels. In this model, we define the constants K/sub R/ as green minus red and K/sub B/ as green minus blue. For real-world images, the contrasts of K/sub R/ and K/sub B/ are quite flat over a small region and this property is suitable for interpolation. The main contribution of this paper is that we propose a low-complexity interpolation method to improve the image quality. We show that the frequency response of the proposed method is better than the conventional methods. Simulation results also verify that the proposed method obtain superior image quality on typical images. The luminance channel of the proposed method outperforms by 6.34-dB peak SNR the bilinear method, and the chrominance channels have a 7.69-dB peak signal-to-noise ratio improvement on average. Furthermore, the complexity of the proposed method is comparable to conventional bilinear interpolation. It requires only add and shift operations to implement.
Sub-pixel color edge detection by using binary quaternion-moment-preserving thresholding technique

This paper presents a new moment-preserving thresholding technique, called the binary quaternion-moment-preserving (BQMP) thresholding, for color image data. Based on representing color data by the quaternions, the statistical parameters of color data can be expressed through the definition of quaternion moments. Analytical formulas of the BQMP thresholding can thus be determined by using the algebra of the quaternions. The computation time for the BQMP thresholding is of order of data size. Employing the BQMP thresholding, quaternion-moment-based operators are designed for the applications of color image processing, such as color image compression and subpixel color edge detection. The experimental results showed that the proposed operators can be used as a tool for color image processing.
Deriving new quasi-orthogonal space-time block codes and relaxed designing viewpoints with full transmit diversity

It has been shown that a complex orthogonal design that provides full diversity and full transmission rate is not possible for more than two transmit antennas. The paper presents a new class of quasi-orthogonal space-time block codes using a group-theoretic method. The new designs can achieve full diversity for quadrature phase-shift-keying modulation, like the system using rotated constellations. Based upon the analysis of the new codes, a relaxed designing viewpoint for full diversity is proposed for arbitrary signal constellations.
Closed-form design of all-pass fractional delay filters

In this letter, we propose a novel all-pass (AP) fractional delay filter whose denominator polynomial is obtained by truncating the power series of a certain function. This function is derived from the frequency response of the denominator whose magnitude response is related to the desired phase response through the Hilbert transform since the denominator of a stable AP filter is of minimum phase. The target function and corresponding power series are calculated analytically and expressed in closed form. The closed-form expressions facilitate the analysis of stability. According to the properties for the coefficients of the denominator polynomial, we show that the proposed AP filter is stable for positive delay. Numerical examples indicate that the phase delays of the proposed filters are flat around DC.
Discrete Laguerre Gaussian Transforms and Their Applications

Laguerre Gaussian functions serve as a complete and orthonormal basis for a variety of physical problems, such as 2D isotropic quantum harmonic oscillators and circularly symmetric laser modes. In this paper, we propose “discrete Laguerre Gaussian functions,” which are defined such that some elegant physical properties are preserved and a fast computation algorithm of complexity O(N logN) is available. Discrete Laguerre Gaussian transforms, as introduced in this paper, inherit nice properties from discrete Laguerre Gaussian functions and admit signal analysis over circularly symmetric patterns. It is demonstrated through examples that discrete Laguerre Gaussian transforms find applications in circular pattern keypoints selection, object detection, image compression, rotational invariance feature for pattern recognition, and rotational angle estimation.
Compression of halftone video for electronic paper

Video halftoning is a key technology for use in the innovative display - electronic paper (e-paper). Since e-paper is power-limited, halftone video compression becomes an emerging issue but is still relatively unexplored. In this paper, this issue is addressed and a novel halftone video compression scheme is proposed. Our scheme is mainly composed of three components: block decomposition, block-based halftone quantization, and source coding. We evaluate the proposed method via lossless halftone video compression comparison with the famous standard, JBIG2. In addition, we demonstrate the rate-distortion performance of the proposed lossy halftone video compression method.
Multiple blocks update algorithm for matching pursuit video coding

Matching pursuit (MP) video coding has been demonstrated to attain a better coding performance than DCT-based video coding in terms of PSNR and perceptual quality at very low bit rates. However, because of its massive computational complexity, the MP algorithm is usually only approximated. By approximating a residual in a subspace, we propose a multiple blocks search and update algorithm in MP video coding to achieve a faster and better MP approximation. In this paper, we evaluate the performance and compare it to the traditional one-block search algorithms. The experimental results show that our proposed algorithm can significantly improve the coding performance and encoding time.
Sparse FIR notch filter design and its application

A technique for designing a sparse FIR notch filter is presented. First, a sparse property of the ideal notch filter, whose notch frequency has the form (q/2p)/spl pi/ is derived, where p and q are coprime integers. Then, the Lagrange multiplier method is used to obtain the coefficients of the sparse notch filter which is optimal in the least-squares sense. Next, a design example is presented to demonstrate the effectiveness of this approach. Finally, a sparse notch filter is applied to eliminate the 60 Hz powerline interference superimposed on the electrocardiogram signals.
Weighted Low-Rank Approximation of General Complex Matrices and Its Application in the Design of 2-D Digital Filters

In this brief we present a method for the weighted low-rank approximation of general complex matrices along with an algorithmic development for its computation. The method developed can be viewed as an extension of the conventional singular value decomposition to include a nontrivial weighting matrix in the approximation error measure. It is shown that the optimal rank-K weighted approximation can be achieved by computing K generalized Schmidt pairs and an iterative algorithm is presented to compute them. Application of the proposed algorithm to the design of FIR two-dimensional (2-D) digital filters is described to demonstrate the usefulness of the algorithm proposed.
Constellation Expansion Free Quasi-Orthogonal Space-Time Block Codes on Square Lattice Constellations with Full Diversity and High Coding Gains

This article presents a set of quasi-orthogonal space-time block codes for four transmit antennas that achieves full diversity and high coding gain whenever a square lattice constellation is adopted. From the simulation results, the new designs perform very closely to quasi-orthogonal codes with constellation rotations. Without a search of the optimal rotation angle and any constellation expansion, our new codes yield an advantageous transmission scheme for QPSK and 16-QAM modulations
Compact LBP and WLBP descriptor with magnitude and direction difference for face recognition

In this paper, we propose a novel descriptor for face recognition on grayscale images, depth images and 2D+depth images. It is a compact and effective descriptor computed from the magnitude and the direction difference. It can be concatenated with conventional descriptors such as well-known Local Binary Pattern (LBP) and Weber Local Binary Pattern (WLBP), to enhance their discrimination capability. To evaluate the performance of our descriptor, we conducted extensive experiments on three types of images using four different databases. The experimental results demonstrate the robustness and superiority of our approach, and the performances of our new descriptor surpass that without magnitude and direction difference. At the end, we further compare our descriptor with Convolution Neural Network (CNN) to show the compactness and effectiveness of the proposed approach.
Fast Discrete Linear Canonical Transform Based on CM-CC-CM Decomposition and FFT

In this paper, a discrete LCT (DLCT) irrelevant to the sampling periods and without oversampling operation is developed. This DLCT is based on the well-known CM-CC-CM decomposition, that is, implemented by two discrete chirp multiplications (CMs) and one discrete chirp convolution (CC). This decomposition doesn't use any scaling operation which will change the sampling period or cause the interpolation error. Compared with previous works, DLCT calculated by direct summation and DLCT based on center discrete dilated Hermite functions (CDDHFs), the proposed method implemented by FFTs has much lower computational complexity. The relation between the proposed DLCT and the continuous LCT is also derived to approximate the samples of the continuous LCT. Simulation results show that the proposed method somewhat outperforms the CDDHFs-based method in the approximation accuracy. Besides, the proposed method has approximate additivity property with error as small as the CDDHFs-based method. Most importantly, the proposed method has perfect reversibility, which doesn't hold in many existing DLCTs. With this property, it is unnecessary to develop the inverse DLCT additionally because it can be replaced by the forward DLCT.
Design of IIR multi-band filters using IIR all-pass eigenfilters

An efficient method is proposed to design infinite impulse response (IIR) all-pass filters for synthesizing general multiband filters of low sensitivity. The method is based on minimizing a quadratic measure of the error derived from the phase design of a certain filter. The problem of stability is of no concern, and the performance of the obtained filter is comparable to that of existing methods. The solution is obtained directly with no need for iteration. The complex coefficient filters can also be designed with minor modification of the proposed method.<<ETX>>
Limited color display for compressed image and video

Many display devices nowadays still allow a limited number of colors, called color palette, to be displayed simultaneously. Besides, images and videos in most World Wide Web databases are in compressed formats. Therefore, it becomes an important issue to retrieve a suitable color palette from compressed domain in order to have fast and faithful color reproduction for these devices. In this paper, the color palette design methods for compressed images and videos are presented. The proposed approaches use the reduced, rather than the whole, image for the color palette design to avoid the heavy computation in image or video decompression. Also, for compressed videos, a shifting-window scheme is proposed to smooth out color variations in the change of color palette. In these methods, we extend the dependent scalar quantization algorithm of a single image to accomplish the color palette design. Experimental results show that the output image quality of the proposed methods is acceptable to human eyes. In addition, empirical results show that the proposed shifting-window scheme can reduce the main problem of displaying quantized image sequences, screen flicker.
A unified approach to the design of quadrantally symmetric linear-phase two-dimensional FIR digital filters by eigenfilter approach

Instead of the design procedures restricted to same special filter types, a unified approach is proposed to design sixteen possible cases for quadrantally symmetric linear-phase 2-D FIR filters. The original forms of the sixteen possible cases are formulated properly such that the eigenfilter method can design them with the same approach. The conversions between the filter coefficients are tabulated in a complete table. Also two numerical examples are shown to demonstrate the usefulness and flexibility of the present approach.
Design of equiripple FIR filters with constraint using a multiple exchange algorithm

We propose a method of designing equiripple linear-phase FIR filters with linear constraint by using the Remez exchange algorithm. A novel technique is derived to convert a linearly constrained problem into an equivalent unconstrained one. We proposed a technique to modify the original desired frequency response so that the original linear constraint can be reduced to a simpler one (the null constraint) for the new target frequency response. The filter with null constraint can be designed without constraint by transformation of the original basis functions. The transformation is represented by a basis for the null space of the constraint. In this paper, we show that the transformed basis set also forms a Tchebycheff set. This fact indicates the proposed design is optimal in the Tchebycheff sense. The optimal filter is deigned by the Remez method according to the new target frequency response in transformed basis. Design examples suggest that the proposed algorithm converges fast and stably.
Adaptive IIR notch filter based on least mean p-power error criterion

A new second-order IIR adaptive notch filter (ANF) algorithm based on least-mean-p-power (LMP) error criterion is investigated. When the ANF is used to cancel 60-Hz interference in the recording of electrocardiograms (ECG), the performance of this adaptive algorithm with p=1 is better than that of the conventional least-mean-square (LMS, p=2) algorithm. Furthermore, when the ANF is applied to estimate the frequency of sinusoid embedded in white noise, this algorithm with p=3 has better statistical accuracy than the LMS algorithm. Simulation results are presented to demonstrate the effectiveness of the proposed ANF algorithm.
Closed Form Variable Fractional Time Delay Using FFT

In this letter, a novel tunable frequency response is proposed for variable fractional delay filter with careful consideration on conjugate symmetry. This proposed fractional delay method can be efficiently realized by FFT using the tunable fractional delay parameter. Its equivalent closed form to windowing method is derived and presented. Several comparisons to other windowing methods are also demonstrated, such as the magnitude response, group delay, and approximation error between ideal frequency response.
Relationships among digital one/half band filters, low/high order differentiators and discrete/differentiating Hilbert transformers

It is shown that there exists a close relationship among digital one/half band filters, low/high order differentiators, and discrete/differentiating Hilbert transformers. An attempt is made to present a complete picture of their interrelationships and conversions between each other. A table and some block diagrams have been developed for their impulse response connections, and a design example is also given for illustration.<<ETX>>
Closed-form design of generalized maximally flat low-pass FIR filters using generating functions

In this paper, we propose a closed-form design of the generalized maximally flat low-pass FIR filters. By representing the transfer function as the Bernstein polynomial form, a simple generating function of the weighting coefficients is derived. We show that the linear phase maximally flat FIR filters and the nonlinear phase maximally flat half-band FIR filters are both special cases of the proposed filter. Closed-form expressions of both linear and nonlinear phase maximally flat FIR filters with prescribed degrees of flatness and delay can be easily obtained by the proposed method.
Design of 2D FIR digital filters by McClellan transformation and least squares eigencontour mapping

A powerful eigenfilter approach is proposed to determine the optimal coefficients of McClellan transformation. It can design arbitrary shape transformation contours to map from 1D prototypes to 2D FIR filters very effectively. This paper presents the design methods for 2D fan filters with general slope and inclination angle, elliptically symmetric filters of arbitrary orientation, circularly symmetric filters, and diamond-shaped filters. Several numerical examples are given to demonstrate the usefulness and the efficiency of the present method.