Pub Date : 2026-01-13DOI: 10.1016/j.dsp.2026.105913
Yihan Wang , Yongfang Wang , Zhijun Fang , Tengyao Cui
Existing Point Cloud Geometry Compression (PCGC) methods often inadequately handle non-uniform point density and fail to fully exploit multi-scale contextual features, limiting their efficiency and reconstruction quality. To bridge this gap, we argue that an effective solution must jointly addresses local geometric adaptation and the aggregation of multi-scale contextual features. Accordingly, we propose a novel PCGC method, consisting of Global-Local Feature Extraction Network (GLFE-Net), Multi-scale Feature Enhancement Network (MFE-Net), and Coordinates Reconstruction based on Offset (CRO). The GLFE-Net incorporates Local Adaptive Density (LAD) to address the non-uniform density distribution and Global-Local Context Differential (GLCD) module to fuse local and global features. The MFE-Net employs the Feature Extraction based on Offset-attention (FEO) module to enhance the feature expression ability, and utilizes the Multi-scale Semantics Fusion (MSF) module to optimize the multi-scale feature fusion. The CRO module utilizes the learnable offset mechanism for high-fidelity reconstruction. Experimental results demonstrate that our method achieves significant improvements, with Peak Signal-to-Noise Ratio (PSNR) gains of up to 29.25 dB (D1) and 27.31 dB (D2) over the existing PCGC methods. This work provides an effective solution for high performance PCGC method by jointly addressing the key challenges of density adaptation and multi-scale feature learning.
现有的点云几何压缩(PCGC)方法往往不能充分处理非均匀点密度,不能充分利用多尺度上下文特征,限制了其效率和重建质量。为了弥补这一差距,我们认为一个有效的解决方案必须同时解决局部几何适应和多尺度上下文特征的聚集。为此,我们提出了一种新的PCGC方法,包括全局局部特征提取网络(GLFE-Net)、多尺度特征增强网络(MFE-Net)和基于偏移量的坐标重建(CRO)。GLFE-Net采用局部自适应密度(LAD)来解决密度分布不均匀的问题,采用全局-局部上下文差分(GLCD)模块来融合局部和全局特征。MFE-Net采用基于偏移注意力的特征提取(FEO)模块来增强特征表达能力,并利用多尺度语义融合(MSF)模块来优化多尺度特征融合。CRO模块利用可学习偏移机制实现高保真重建。实验结果表明,我们的方法取得了显著的改进,与现有的PCGC方法相比,峰值信噪比(PSNR)增益高达29.25 dB (D1)和27.31 dB (D2)。该工作通过共同解决密度自适应和多尺度特征学习的关键挑战,为高性能PCGC方法提供了有效的解决方案。
{"title":"Towards point cloud geometry compression via global-local and multi-scale feature learning","authors":"Yihan Wang , Yongfang Wang , Zhijun Fang , Tengyao Cui","doi":"10.1016/j.dsp.2026.105913","DOIUrl":"10.1016/j.dsp.2026.105913","url":null,"abstract":"<div><div>Existing Point Cloud Geometry Compression (PCGC) methods often inadequately handle non-uniform point density and fail to fully exploit multi-scale contextual features, limiting their efficiency and reconstruction quality. To bridge this gap, we argue that an effective solution must jointly addresses local geometric adaptation and the aggregation of multi-scale contextual features. Accordingly, we propose a novel PCGC method, consisting of Global-Local Feature Extraction Network (GLFE-Net), Multi-scale Feature Enhancement Network (MFE-Net), and Coordinates Reconstruction based on Offset (CRO). The GLFE-Net incorporates Local Adaptive Density (LAD) to address the non-uniform density distribution and Global-Local Context Differential (GLCD) module to fuse local and global features. The MFE-Net employs the Feature Extraction based on Offset-attention (FEO) module to enhance the feature expression ability, and utilizes the Multi-scale Semantics Fusion (MSF) module to optimize the multi-scale feature fusion. The CRO module utilizes the learnable offset mechanism for high-fidelity reconstruction. Experimental results demonstrate that our method achieves significant improvements, with Peak Signal-to-Noise Ratio (PSNR) gains of up to 29.25 dB (D1) and 27.31 dB (D2) over the existing PCGC methods. This work provides an effective solution for high performance PCGC method by jointly addressing the key challenges of density adaptation and multi-scale feature learning.</div></div>","PeriodicalId":51011,"journal":{"name":"Digital Signal Processing","volume":"173 ","pages":"Article 105913"},"PeriodicalIF":3.0,"publicationDate":"2026-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-13DOI: 10.1016/j.dsp.2026.105909
Ziqi Yan , Zhichao Zhang
To address the limitations of the graph fractional Fourier transform (GFRFT) Wiener filtering and the traditional joint time-vertex fractional Fourier transform (JFRFT) Wiener filtering, this study proposes a filtering method based on the hyper-differential form of the JFRFT. The gradient backpropagation mechanism is employed to establish the adaptive selection of transform order pair and filter coefficients. First, leveraging the hyper-differential form of the GFRFT and the fractional Fourier transform, the hyper-differential form of the JFRFT is constructed and its properties are analyzed. Second, time-varying graph signals are divided into dynamic graph sequences of equal span along the temporal dimension. A spatiotemporal joint representation is then established through vectorized reorganization, followed by the joint time-vertex Wiener filtering. Furthermore, by rigorously proving the differentiability of the transform orders, both the transform orders and filter coefficients are embedded as learnable parameters within a neural network architecture. Through gradient backpropagation, their synchronized iterative optimization is achieved, constructing a parameters-adaptive learning filtering framework. This method leverages a model-driven approach to learn the optimal transform order pair and filter coefficients. Experimental results indicate that the proposed framework improves the time-varying graph signals denoising performance, while reducing the computational burden of the traditional grid search strategy.
{"title":"Trainable joint time-vertex fractional Fourier transform","authors":"Ziqi Yan , Zhichao Zhang","doi":"10.1016/j.dsp.2026.105909","DOIUrl":"10.1016/j.dsp.2026.105909","url":null,"abstract":"<div><div>To address the limitations of the graph fractional Fourier transform (GFRFT) Wiener filtering and the traditional joint time-vertex fractional Fourier transform (JFRFT) Wiener filtering, this study proposes a filtering method based on the hyper-differential form of the JFRFT. The gradient backpropagation mechanism is employed to establish the adaptive selection of transform order pair and filter coefficients. First, leveraging the hyper-differential form of the GFRFT and the fractional Fourier transform, the hyper-differential form of the JFRFT is constructed and its properties are analyzed. Second, time-varying graph signals are divided into dynamic graph sequences of equal span along the temporal dimension. A spatiotemporal joint representation is then established through vectorized reorganization, followed by the joint time-vertex Wiener filtering. Furthermore, by rigorously proving the differentiability of the transform orders, both the transform orders and filter coefficients are embedded as learnable parameters within a neural network architecture. Through gradient backpropagation, their synchronized iterative optimization is achieved, constructing a parameters-adaptive learning filtering framework. This method leverages a model-driven approach to learn the optimal transform order pair and filter coefficients. Experimental results indicate that the proposed framework improves the time-varying graph signals denoising performance, while reducing the computational burden of the traditional grid search strategy.</div></div>","PeriodicalId":51011,"journal":{"name":"Digital Signal Processing","volume":"173 ","pages":"Article 105909"},"PeriodicalIF":3.0,"publicationDate":"2026-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-13DOI: 10.1016/j.dsp.2026.105914
Yang He , Ning Cao , Hao Lu , Can Hu , Yajuan Guo
Continuous Phase Modulation (CPM) signals offer excellent spectral efficiency and constant envelope properties for wireless communications, but traditional detection methods suffer from prohibitive computational complexity. This paper presents CPMNet, a novel deep learning-based detection framework that addresses these limitations through an enhanced residual network architecture incorporating spatial attention mechanisms, multi-scale feature fusion, and bidirectional LSTM networks. CPMNet performs sequence-to-sequence detection without requiring channel estimation or equalization. Experimental results on Advanced Range Telemetry (ARTM) Tier 2 signals show performance varies with modulation complexity: while exhibiting 2–4 dB gaps compared to Maximum Likelihood Sequence Detection (MLSD) in high signal-to-noise ratio (SNR) AWGN channels for lower-order modulations, CPMNet maintains robust performance for high-order modulations where MLSD becomes impractical. In multipath fading channels, CPMNet significantly outperforms MLSD by 3–6 dB across various conditions, demonstrating superior resilience to channel impairments. The framework exhibits excellent generalization with only 1–2 dB degradation in unseen environments. Most critically, CPMNet maintains constant computational complexity regardless of CPM parameters, contrasting sharply with MLSD’s exponential complexity growth, making it particularly advantageous for high-order CPM signals that are computationally prohibitive for traditional methods.
{"title":"CPMNet: an enhanced residual network for continuous phase modulation signal detection","authors":"Yang He , Ning Cao , Hao Lu , Can Hu , Yajuan Guo","doi":"10.1016/j.dsp.2026.105914","DOIUrl":"10.1016/j.dsp.2026.105914","url":null,"abstract":"<div><div>Continuous Phase Modulation (CPM) signals offer excellent spectral efficiency and constant envelope properties for wireless communications, but traditional detection methods suffer from prohibitive computational complexity. This paper presents CPMNet, a novel deep learning-based detection framework that addresses these limitations through an enhanced residual network architecture incorporating spatial attention mechanisms, multi-scale feature fusion, and bidirectional LSTM networks. CPMNet performs sequence-to-sequence detection without requiring channel estimation or equalization. Experimental results on Advanced Range Telemetry (ARTM) Tier 2 signals show performance varies with modulation complexity: while exhibiting 2–4 dB gaps compared to Maximum Likelihood Sequence Detection (MLSD) in high signal-to-noise ratio (SNR) AWGN channels for lower-order modulations, CPMNet maintains robust performance for high-order modulations where MLSD becomes impractical. In multipath fading channels, CPMNet significantly outperforms MLSD by 3–6 dB across various conditions, demonstrating superior resilience to channel impairments. The framework exhibits excellent generalization with only 1–2 dB degradation in unseen environments. Most critically, CPMNet maintains constant computational complexity regardless of CPM parameters, contrasting sharply with MLSD’s exponential complexity growth, making it particularly advantageous for high-order CPM signals that are computationally prohibitive for traditional methods.</div></div>","PeriodicalId":51011,"journal":{"name":"Digital Signal Processing","volume":"173 ","pages":"Article 105914"},"PeriodicalIF":3.0,"publicationDate":"2026-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146079691","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-12DOI: 10.1016/j.dsp.2026.105912
Xuchao Bai , Yuxian Wang , Chunfang Zhang
This paper proposes a novel method based on an improved sparrow search algorithm, variational mode decomposition (VMD), and joint wavelet threshold denoising (ISSA-VMD-JWTD). During the optimization process, cubic mapping is utilized to initialize the sparrow population, while weighted kurtosis serves as the fitness function to optimize the critical parameters of Variational Mode Decomposition (VMD). In the decomposition and denoising procedure, the vibration signal is first decomposed using VMD with the optimal parameter combination, followed by adaptive selection of effective components to eliminate low-frequency noise. Subsequently, a multi-objective optimization mechanism is established to autonomously determine the optimal wavelet threshold parameters for different wavelet families (including dbN, symN, and coifN). Parallel secondary denoising is then performed on the reconstructed ISSA-VMD signal using the optimized parameters from each wavelet family. Finally, the denoising results from multiple wavelet families are integrated through a variance-based weighting strategy to produce the ultimate denoised signal. Experimental results demonstrate that the proposed method significantly enhances the signal-to-noise ratio of denoised signals compared to other denoising approaches, while exhibiting superior adaptability and robustness for rolling bearing vibration signals under diverse operating conditions.
{"title":"Research on denoising of rolling bearing vibration signals based on the ISSA-VMD-JWTD method","authors":"Xuchao Bai , Yuxian Wang , Chunfang Zhang","doi":"10.1016/j.dsp.2026.105912","DOIUrl":"10.1016/j.dsp.2026.105912","url":null,"abstract":"<div><div>This paper proposes a novel method based on an improved sparrow search algorithm, variational mode decomposition (VMD), and joint wavelet threshold denoising (ISSA-VMD-JWTD). During the optimization process, cubic mapping is utilized to initialize the sparrow population, while weighted kurtosis serves as the fitness function to optimize the critical parameters of Variational Mode Decomposition (VMD). In the decomposition and denoising procedure, the vibration signal is first decomposed using VMD with the optimal parameter combination, followed by adaptive selection of effective components to eliminate low-frequency noise. Subsequently, a multi-objective optimization mechanism is established to autonomously determine the optimal wavelet threshold parameters for different wavelet families (including dbN, symN, and coifN). Parallel secondary denoising is then performed on the reconstructed ISSA-VMD signal using the optimized parameters from each wavelet family. Finally, the denoising results from multiple wavelet families are integrated through a variance-based weighting strategy to produce the ultimate denoised signal. Experimental results demonstrate that the proposed method significantly enhances the signal-to-noise ratio of denoised signals compared to other denoising approaches, while exhibiting superior adaptability and robustness for rolling bearing vibration signals under diverse operating conditions.</div></div>","PeriodicalId":51011,"journal":{"name":"Digital Signal Processing","volume":"173 ","pages":"Article 105912"},"PeriodicalIF":3.0,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146039115","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-12DOI: 10.1016/j.dsp.2026.105895
Lei Gao, Taichang Tian, Luosheng Wen
Time-series clustering is an important method in data mining, which is widely used in various fields. However, the traditional clustering algorithms directly deal with the time-series data, which will lead to the serious issue of “dimensionality catastrophe”. It is an important method to capture the local features of time-series data by using the neighbor information. In this paper, we propose a hierarchical graph clustering algorithm (CTNG) based on common tightest neighbors(CTN), which is able to cluster various kinds of complex streaming data and noisy data by using the ratio of common tightest neighbors between data points to determine whether the edges are connected in the tightest neighbors graph(TNG) or not. In order to solve the issue of “dimension disaster”, combined with the local linear embedding algorithm (LLE), this paper proposes a time-series clustering algorithm based on LLE_CTNG, which can make full use of the local structure of the data to realize the dimensionality reduction and clustering. Through a large number of experiments, it is shown that the algorithm has superior and stable clustering performance, has certain advantages in running speed, and is robust to the number of the tightest neighbors parameter.
{"title":"Time-series clustering algorithm based on common tightest neighbors and local embedding","authors":"Lei Gao, Taichang Tian, Luosheng Wen","doi":"10.1016/j.dsp.2026.105895","DOIUrl":"10.1016/j.dsp.2026.105895","url":null,"abstract":"<div><div>Time-series clustering is an important method in data mining, which is widely used in various fields. However, the traditional clustering algorithms directly deal with the time-series data, which will lead to the serious issue of “dimensionality catastrophe”. It is an important method to capture the local features of time-series data by using the neighbor information. In this paper, we propose a hierarchical graph clustering algorithm (CTNG) based on common tightest neighbors(CTN), which is able to cluster various kinds of complex streaming data and noisy data by using the ratio of common tightest neighbors between data points to determine whether the edges are connected in the tightest neighbors graph(TNG) or not. In order to solve the issue of “dimension disaster”, combined with the local linear embedding algorithm (LLE), this paper proposes a time-series clustering algorithm based on LLE_CTNG, which can make full use of the local structure of the data to realize the dimensionality reduction and clustering. Through a large number of experiments, it is shown that the algorithm has superior and stable clustering performance, has certain advantages in running speed, and is robust to the number of the tightest neighbors parameter.</div></div>","PeriodicalId":51011,"journal":{"name":"Digital Signal Processing","volume":"173 ","pages":"Article 105895"},"PeriodicalIF":3.0,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146039116","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-11DOI: 10.1016/j.dsp.2026.105896
Mukul Chauhan, Waseem Z. Lone, Amit K. Verma
This paper introduces a novel time–frequency distribution, referred to as the two-dimensional non-separable quadratic-phase Wigner distribution (2D-NSQPWD), formulated within the framework of the two-dimensional non-separable quadratic-phase Fourier transform (2D-NSQPFT). The proposed distribution extends the classical two-dimensional Wigner distribution (2D-WD) through a convolution-based formulation that incorporates the structural characteristics of the 2D-NSQPFT, thereby enabling an effective representation of complex, non-separable signal structures. We rigorously establish several key properties of the 2D-NSQPWD, including time and frequency shift invariance, marginal behavior, conjugate symmetry, convolution relations, and Moyal’s identity. The effectiveness of the distribution is demonstrated through its application to single-, bi-, and tri-component two-dimensional linear frequency-modulated (2D-LFM) signals. Finally, simulations show that the proposed transform exhibits superior performance in cross-term suppression and signal localization compared to existing transforms.
{"title":"A novel two-dimensional Wigner distribution framework via the quadratic phase Fourier transform with a non-separable kernel","authors":"Mukul Chauhan, Waseem Z. Lone, Amit K. Verma","doi":"10.1016/j.dsp.2026.105896","DOIUrl":"10.1016/j.dsp.2026.105896","url":null,"abstract":"<div><div>This paper introduces a novel time–frequency distribution, referred to as the two-dimensional non-separable quadratic-phase Wigner distribution (2D-NSQPWD), formulated within the framework of the two-dimensional non-separable quadratic-phase Fourier transform (2D-NSQPFT). The proposed distribution extends the classical two-dimensional Wigner distribution (2D-WD) through a convolution-based formulation that incorporates the structural characteristics of the 2D-NSQPFT, thereby enabling an effective representation of complex, non-separable signal structures. We rigorously establish several key properties of the 2D-NSQPWD, including time and frequency shift invariance, marginal behavior, conjugate symmetry, convolution relations, and Moyal’s identity. The effectiveness of the distribution is demonstrated through its application to single-, bi-, and tri-component two-dimensional linear frequency-modulated (2D-LFM) signals. Finally, simulations show that the proposed transform exhibits superior performance in cross-term suppression and signal localization compared to existing transforms.</div></div>","PeriodicalId":51011,"journal":{"name":"Digital Signal Processing","volume":"173 ","pages":"Article 105896"},"PeriodicalIF":3.0,"publicationDate":"2026-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981796","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-10DOI: 10.1016/j.dsp.2026.105893
Markus Sifft, Armin Ghorbanietemad, Fabian Wagner, Daniel Hägele
Higher-order spectra (Brillinger’s polyspectra) offer powerful methods for solving critical problems in signal processing and data analysis. Despite their significant potential, their practical use has remained limited due to unresolved mathematical issues in spectral estimation, including the absence of unbiased and consistent estimators and the high computational cost associated with evaluating multidimensional spectra. Consequently, existing tools frequently produce artifacts-no existing software library correctly implements Brillinger’s cumulant-based trispectrum-or fail to scale effectively to real-world data volumes, leaving crucial applications like multi-detector spectral analysis largely unexplored.
In this paper, we revisit higher-order spectra from a modern perspective, addressing the root causes of their historical underuse. We reformulate higher-order spectral estimation using recently derived multivariate k-statistics, yielding unbiased and consistent estimators that eliminate spurious artifacts and precisely align with Brillinger’s theoretical definitions. Our methodology covers single- and multi-channel spectral analysis up to the bispectrum (third order) and trispectrum (fourth order), enabling robust investigations of inter-frequency coupling, non-Gaussian behavior, and time-reversal symmetry breaking. Additionally, we introduce quasi-polyspectra to uncover non-stationary, time-dependent higher-order features. We implement these new estimators in SignalSnap, an open-source GPU-accelerated library capable of efficiently analyzing datasets exceeding hundreds of gigabytes within minutes.
In applications such as continuous quantum measurements, SignalSnap’s rigorous estimators enable precise quantitative matching between experimental data and theoretical models. With detailed derivations and illustrative examples, this work provides the theoretical and computational foundation necessary for establishing higher-order spectra as a reliable, standard tool in modern signal analysis.
{"title":"Correct estimation of higher-order spectra: From theoretical challenges to practical multi-channel implementation in SignalSnap","authors":"Markus Sifft, Armin Ghorbanietemad, Fabian Wagner, Daniel Hägele","doi":"10.1016/j.dsp.2026.105893","DOIUrl":"10.1016/j.dsp.2026.105893","url":null,"abstract":"<div><div>Higher-order spectra (Brillinger’s polyspectra) offer powerful methods for solving critical problems in signal processing and data analysis. Despite their significant potential, their practical use has remained limited due to unresolved mathematical issues in spectral estimation, including the absence of unbiased and consistent estimators and the high computational cost associated with evaluating multidimensional spectra. Consequently, existing tools frequently produce artifacts-no existing software library correctly implements Brillinger’s cumulant-based trispectrum-or fail to scale effectively to real-world data volumes, leaving crucial applications like multi-detector spectral analysis largely unexplored.</div><div>In this paper, we revisit higher-order spectra from a modern perspective, addressing the root causes of their historical underuse. We reformulate higher-order spectral estimation using recently derived multivariate k-statistics, yielding unbiased and consistent estimators that eliminate spurious artifacts and precisely align with Brillinger’s theoretical definitions. Our methodology covers single- and multi-channel spectral analysis up to the bispectrum (third order) and trispectrum (fourth order), enabling robust investigations of inter-frequency coupling, non-Gaussian behavior, and time-reversal symmetry breaking. Additionally, we introduce quasi-polyspectra to uncover non-stationary, time-dependent higher-order features. We implement these new estimators in SignalSnap, an open-source GPU-accelerated library capable of efficiently analyzing datasets exceeding hundreds of gigabytes within minutes.</div><div>In applications such as continuous quantum measurements, SignalSnap’s rigorous estimators enable precise quantitative matching between experimental data and theoretical models. With detailed derivations and illustrative examples, this work provides the theoretical and computational foundation necessary for establishing higher-order spectra as a reliable, standard tool in modern signal analysis.</div></div>","PeriodicalId":51011,"journal":{"name":"Digital Signal Processing","volume":"173 ","pages":"Article 105893"},"PeriodicalIF":3.0,"publicationDate":"2026-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981797","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Small object detection remains a critical challenge due to limited pixel representation and uneven spatial distribution. In the absence of sufficient contextual information, it is difficult to extract discriminative and complete features for accurate detection. By analyzing multi-scale feature fusion within modern detectors, we proposed a Multi-stage Path Aggregation module(MPAM) composed of the Parallel Residual Fusion Module(PRFM) and the Differential Path Channel Aggregation Module(DPCAM). Through decomposing the path aggregation operation into multiple stages, MPAM significantly enhanced the feature maps’ capacity to accommodate and process contextual information. PRFM captured texture and semantic information from the multi-scale feature maps through skip connections. Moreover, a channel branch was added to enable the dynamic distribution of attention weights across both the channel and spatial dimensions. DPCAM is proposed to balance channel and spatial information from different feature maps through channel expansion operation. Additionally, Deep-wise Partial Attention(DPA) is designed to enhance the ability of representing features for small objects within complex backgrounds by balancing weights between local and global information. Integrated into popular detectors, our method delivers consistent gains. Compared with yolov8s, mAP50:95 of our method improved by 3.7% on VisDrone and 3.2% on MS COCO, respectively. Experimental results validate the effectiveness of the proposed module in significantly enhancing small object detection accuracy.
{"title":"A multi-stage path aggregation module for small object detection on drone-captured scenarios","authors":"Wenyuan Fan , Xuemei Xu , Zhaohui Jiang , Zehan Zhu","doi":"10.1016/j.dsp.2026.105901","DOIUrl":"10.1016/j.dsp.2026.105901","url":null,"abstract":"<div><div>Small object detection remains a critical challenge due to limited pixel representation and uneven spatial distribution. In the absence of sufficient contextual information, it is difficult to extract discriminative and complete features for accurate detection. By analyzing multi-scale feature fusion within modern detectors, we proposed a Multi-stage Path Aggregation module(MPAM) composed of the Parallel Residual Fusion Module(PRFM) and the Differential Path Channel Aggregation Module(DPCAM). Through decomposing the path aggregation operation into multiple stages, MPAM significantly enhanced the feature maps’ capacity to accommodate and process contextual information. PRFM captured texture and semantic information from the multi-scale feature maps through skip connections. Moreover, a channel branch was added to enable the dynamic distribution of attention weights across both the channel and spatial dimensions. DPCAM is proposed to balance channel and spatial information from different feature maps through channel expansion operation. Additionally, Deep-wise Partial Attention(DPA) is designed to enhance the ability of representing features for small objects within complex backgrounds by balancing weights between local and global information. Integrated into popular detectors, our method delivers consistent gains. Compared with yolov8s, mAP50:95 of our method improved by 3.7% on VisDrone and 3.2% on MS COCO, respectively. Experimental results validate the effectiveness of the proposed module in significantly enhancing small object detection accuracy.</div></div>","PeriodicalId":51011,"journal":{"name":"Digital Signal Processing","volume":"173 ","pages":"Article 105901"},"PeriodicalIF":3.0,"publicationDate":"2026-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981078","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-10DOI: 10.1016/j.dsp.2026.105904
Hao Ming , Hanping Hu , Jun Zheng
For chaotic cryptography to advance toward practical deployment, it is necessary to pay attention not only to the security issues of chaotic systems but also to problems such as the actual degradation of digital performance and system synchronization. Regarding the security of the chaotic system itself, its characteristic information (including parameters, the structure of coupled chaotic systems, etc.) provides critical entry points for attackers. If these characteristics remain static, chaotic cryptography becomes increasingly vulnerable to cryptanalysis. In this paper, a time-variant stream cipher based on a nondegenerate and coupled chaotic system is proposed. The analog-digital hybrid technique is employed to solve the dynamical degradation in the digital field, and digital adaptive pulse control for synchronization. The coupling structure, delay, and parameter of the coupled chaos are dynamically varied following a time-variant mechanism to enhance the security. The practical effectiveness is demonstrated by FPGA-FPAA collaborative hardware design, wherein an event-triggered synchronization scheme is also presented for hardware implementation. Experimental results and theoretical analyses show that the proposed cipher can provide high-quality and robust keystreams for wide cryptographic applications. The construction strategy and components of the proposed cryptosystem are beneficial to motivate chaotic cipher designs and applications.
{"title":"Design and hardware implementation of a dynamically variable chaotic stream cipher system with analog-Digital hybrid control and synchronization","authors":"Hao Ming , Hanping Hu , Jun Zheng","doi":"10.1016/j.dsp.2026.105904","DOIUrl":"10.1016/j.dsp.2026.105904","url":null,"abstract":"<div><div>For chaotic cryptography to advance toward practical deployment, it is necessary to pay attention not only to the security issues of chaotic systems but also to problems such as the actual degradation of digital performance and system synchronization. Regarding the security of the chaotic system itself, its characteristic information (including parameters, the structure of coupled chaotic systems, etc.) provides critical entry points for attackers. If these characteristics remain static, chaotic cryptography becomes increasingly vulnerable to cryptanalysis. In this paper, a time-variant stream cipher based on a nondegenerate and coupled chaotic system is proposed. The analog-digital hybrid technique is employed to solve the dynamical degradation in the digital field, and digital adaptive pulse control for synchronization. The coupling structure, delay, and parameter of the coupled chaos are dynamically varied following a time-variant mechanism to enhance the security. The practical effectiveness is demonstrated by FPGA-FPAA collaborative hardware design, wherein an event-triggered synchronization scheme is also presented for hardware implementation. Experimental results and theoretical analyses show that the proposed cipher can provide high-quality and robust keystreams for wide cryptographic applications. The construction strategy and components of the proposed cryptosystem are beneficial to motivate chaotic cipher designs and applications.</div></div>","PeriodicalId":51011,"journal":{"name":"Digital Signal Processing","volume":"173 ","pages":"Article 105904"},"PeriodicalIF":3.0,"publicationDate":"2026-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146039208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-09DOI: 10.1016/j.dsp.2026.105902
Pengpeng Xie, Ziyang Ding, Qianfan Li, Cong Shi, Shibo Bin
Current image fusion algorithms often face modality preference issues: they either excessively depend on the thermal radiation features of infrared images, leading to the loss of visible light texture details, or they prioritize visible light images, which undermines infrared target detection. This makes it challenging to achieve a dynamic balance and collaborative optimization of information from both modalities in complex scenarios. This asymmetric fusion approach makes it difficult for the system to simultaneously preserve sensitivity to thermal radiation targets while maintaining the ability to resolve texture details under extreme lighting conditions. To address this, the paper proposes an infrared and visible light fusion model that incorporates a gradient-pixel joint constraint. Our approach eliminates the complexity and uncertainty associated with manual feature extraction, while effectively leveraging shallow features through multiple shortcut connections. Within the framework of Generative Adversarial Networks, we design a gradient-pixel joint loss function that strikes a balance between preserving significant targets in the infrared image and maintaining the texture structure in the visible light image, thereby enhancing image detail and retaining high-contrast information. To thoroughly evaluate the performance of the proposed method, we conducted systematic experiments using the TNO and RoadScene benchmark datasets, comparing it with eleven state-of-the-art fusion algorithms. The experimental results demonstrate that the proposed method offers significant advantages in both subjective visual quality and objective evaluation metrics. In terms of qualitative evaluation, the fusion results not only preserve natural lighting transitions but, more importantly, accentuate thermal radiation targets in the infrared image while fully retaining the texture details of the visible light image. Quantitative analysis reveals that the proposed method significantly improves metrics such as Mutual Information (MI) and Spatial Frequency (SF). This provides new insights in the field of multimodal image fusion and contributes to balancing the complementary advantages of different modality features.
{"title":"GPF-GAN: An unsupervised generative adversarial network for joint gradient and pixel-constrained fusion of infrared and visible images","authors":"Pengpeng Xie, Ziyang Ding, Qianfan Li, Cong Shi, Shibo Bin","doi":"10.1016/j.dsp.2026.105902","DOIUrl":"10.1016/j.dsp.2026.105902","url":null,"abstract":"<div><div>Current image fusion algorithms often face modality preference issues: they either excessively depend on the thermal radiation features of infrared images, leading to the loss of visible light texture details, or they prioritize visible light images, which undermines infrared target detection. This makes it challenging to achieve a dynamic balance and collaborative optimization of information from both modalities in complex scenarios. This asymmetric fusion approach makes it difficult for the system to simultaneously preserve sensitivity to thermal radiation targets while maintaining the ability to resolve texture details under extreme lighting conditions. To address this, the paper proposes an infrared and visible light fusion model that incorporates a gradient-pixel joint constraint. Our approach eliminates the complexity and uncertainty associated with manual feature extraction, while effectively leveraging shallow features through multiple shortcut connections. Within the framework of Generative Adversarial Networks, we design a gradient-pixel joint loss function that strikes a balance between preserving significant targets in the infrared image and maintaining the texture structure in the visible light image, thereby enhancing image detail and retaining high-contrast information. To thoroughly evaluate the performance of the proposed method, we conducted systematic experiments using the TNO and RoadScene benchmark datasets, comparing it with eleven state-of-the-art fusion algorithms. The experimental results demonstrate that the proposed method offers significant advantages in both subjective visual quality and objective evaluation metrics. In terms of qualitative evaluation, the fusion results not only preserve natural lighting transitions but, more importantly, accentuate thermal radiation targets in the infrared image while fully retaining the texture details of the visible light image. Quantitative analysis reveals that the proposed method significantly improves metrics such as Mutual Information (MI) and Spatial Frequency (SF). This provides new insights in the field of multimodal image fusion and contributes to balancing the complementary advantages of different modality features.</div></div>","PeriodicalId":51011,"journal":{"name":"Digital Signal Processing","volume":"173 ","pages":"Article 105902"},"PeriodicalIF":3.0,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145950131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}