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Spatial Acoustic Loudspeaker Measurements With a Moving Microphone

AES: Journal of the Audio engineering Society 2025年第1-2期73卷 24-42页

作者： Herzog, Stephan Department of Electrical and Computer Engineering Digital Signal Processing Group RPTU University Kaiserslautern Landau Kaiserslautern Germany

Acoustic loudspeaker measurements are an essential aspect in loudspeaker development and design. Established setups usually require acoustic measurement rooms or chambers where the speaker under test has to be installed for conducting the tests. Furthermore, typical spatial measurements require that the speaker has to be rotated on one or two axes. In addition to the traditional approach, there are different methods that use near-field measurements where the microphone is usually moved and the loudspeaker remains at a fixed position. Both techniques commonly make measurements at discrete points or angles in the spatial domain. In this article, the idea of making impulse response measurements in the near-field while the microphone is in movement is proposed and described. This approach leads to much faster results that can be comparable to the results of fixed-point measurements. The focus here is on the properties and the resulting processing of appropriate test signals and on the experimental verification of the method. This method will be applied to the measurement of line arrays, where directivity is of high interest, but it can also be used for other loudspeaker configurations. © 2025 Audio engineering Society. All rights reserved.

关键词： Strain measurement

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Seeing the light: Hyperspectral retinal imaging as a surrogate marker for early stage Alzheimer's disease

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ACTA OPHTHALMOLOGICA 2025年第S284期103卷

作者： Ghesquiere, Michiel Christinaki, Eirini Van Eijgen, Jan Vandenbulcke, Mathieu Vandenberghe, Rik De Vos, Maarten Stalmans, Ingeborg Department of Neurosciences – Research Group Ophthalmology KU Leuven Leuven Belgium Department of Neurosciences – Research Group Psychiatry KU Leuven Leuven Belgium Department of Neurosciences – Research Group Experimental Neurology KU Leuven Leuven Department of Electrical Engineering (ESAT) – Dynamical Systems Signal Processing and Data Analytics (STADIUS) KU Leuven Leuven Belgium

Aims/Purpose: Alzheimer's disease (AD), the leading cause of dementia, affects millions, underscoring the need for early diagnostic methods. The retina, which can exhibit AD-related pathological processes, offers a promising diagnostic site. This study aims to utilize Hyperspectral Retinal Imaging (HSRI) to differentiate between positive (+) and negative (-) PET-amyloid beta (Aβ) status. Within this cohort, a subset is Aβ+ while remaining cognitively healthy, indicating preclinical amyloid accumulation. Unlike most research targeting later symptomatic stages, our approach could facilitate interventions before clinically apparent neurodegeneration occurs. Methods: Data was used from 37 Aβ- and 25 Aβ+ individuals of which 8 with mild cognitive impairment (MCI). HSRI were captured using an easy-to-use hyperspectral snapshot camera, covering a spectral range of 460–630 nm. Images were taken from primary, inferior, and superior views of the retina, with further regions of interest (ROI) defined in the primary view. After preprocessing, these spectra were used to train machine learning classifiers [1]. Results: The best classifier performance was observed using XGBoost with the superior spectra (AUC = 0.72), and using a Linear Discriminant Analysis classifier in superior quadrants (S1 AUC = 0.74, S2 AUC = 0.68). Lower performance in other ROI underscored the variability in amyloid deposition across the retina, correlating with previous findings that retinal Aβ deposits in AD patients are frequently concentrated in the superior quadrants. Conclusions: We were able to achieve similar performance of previous research in AD patients [1], but in a preclinical cohort of cognitively normal participants up to MCI patients. Consistent with the literature, the superior retinal regions seem most discriminative for Aβ status. Further exploration of the specificity of the HSRI signal will pave the way for early AD detection, potentially improving outcomes through earlier therapeutic i

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Complete coverage path planning strategy for reconfigurable robot with variable footprint

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IEEE Access 2025年 13卷 74446-74456页

作者： Tang, Q.R. Yi, Lim Wan, Ash Yaw Sang Hayat, Abdullah Aamir Le, Anh Vu Elara, Mohan Rajesh Singapore University of Technology and Design ROAR Lab Engineering Product Development Pillar Singapore487372 Singapore United Arab Emirates University Department of Mechanical and Aerospace Engineering United Arab Emirates Ton Duc Thang University Communication and Signal Processing Research Group Faculty of Electrical and Electronics Engineering Ho Chi Minh City700000 Viet Nam

Autonomous mobile robots (AMRs) face challenges in navigating complex environments efficiently. To manoeuvre through both narrow and wide spaces, AMRs require two essential design features: a compact form for tight areas as well as a large configuration with omnidirectional movement for wide spaces. This study utilizes inhouse designed Expand and Collapse Variable Width Robot (ECVWR) to demonstrate effective area coverage. These ECVWR can contract to navigate constrained spaces and expand to optimize coverage in open areas. Existing methods for achieving complete area coverage do not account for the reconfiguration or the change in footprint. To address this issue, we propose the Depth-First Search (DFS) for Complete Coverage Path Planning Strategy (CCPPS) for ECVWRs. This method allows adjustments to the generation of waypoints in CCPPS, minimizing the path length. The simulation study shows that our proposed CCPPS outperforms contemporary state-of-the-art CCPPS, namely, GBNN, exhibiting superior expanded area coverage, reduced travel distance, and enhanced computational efficiency. Moreover real-world experiment to further benchmark the efficacy of our proposed algorithm. The proposed CCPPS is generic and can be extended to other variable footprint robots. © 2013 IEEE.

关键词： Robot programming

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One-bit Compressed Sensing using Generative Models

arXiv

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arXiv 2025年

作者： Kafle, Swatantra Joseph, Geethu Varshney, Pramod K. ANDRO Computational Solutions NY United States Electrical Engineering and Computer Science Department Syracuse University NY United States Signal Processing Systems group Electrical Engineering Mathematics and Computer Science faculty the Delft University of Technology Netherlands

This paper addresses the classical problem of one-bit compressed sensing using a deep learning-based reconstruction algorithm that leverages a trained generative model to enhance the signal reconstruction performance. The generator, a pretrained neural network, learns to map from a low-dimensional latent space to a higher-dimensional set of sparse vectors. This generator is then used to reconstruct sparse vectors from their one-bit measurements by searching over its range. The presented algorithm provides an excellent reconstruction performance because the generative model can learn additional structural information about the signal beyond sparsity. Furthermore, we provide theoretical guarantees on the reconstruction accuracy and sample complexity of the algorithm. Through numerical experiments using three publicly available image datasets, MNIST, Fashion-MNIST, and Omniglot, we demonstrate the superior performance of the algorithm compared to other existing algorithms and show that our algorithm can recover both the amplitude and the direction of the signal from one-bit measurements. © 2025, CC BY.

关键词： Compressed sensing

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Complete coverage path planning for omnidirectional self-reconfigurable cleaning robot using aGBNN

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IEEE Transactions on Automation Science and engineering 2025年

作者： Yi, Lim Hayat, A.A. Wan, Ash Yaw Sang Le, Anh Vu Tang, Q.R. Elara, Mohan Rajesh Singapore University of Technology and Design ROAR LabEngineering Product Development 487372 Singapore Department of Mechanical and Aerospace Engineering Abu Dhabi15551 United Arab Emirates Ton Duc Thang University Communication and Signal Processing Research Group Faculty of Electrical and Electronics Engineering Ho Chi Minh City700000 Viet Nam

Complete coverage path planning (CCPP) is essential for autonomous cleaning robots, particularly in complex and variable environments where traditional, fixed-footprint designs may fall short. This paper presents adaptive Glasius bio-inspired neural network (aGBNN) approach to CCPP, specifically tailored for an omnidirectional self-reconfigurable cleaning robot (OSCR). The aGBNN method dynamically generates a complete coverage path by leveraging the ability to change sweeping footprint of the robot (SFR) assisted by reconfiguring brushes design. The sweeping is carried out both longitudinally and laterally, thereby complementing the omnidirectional locomotion with cleaning. Unlike conventional CCPP algorithms that assume a fixed robot footprint, the proposed aGBNN adapts in real-time to spatial and moving obstacles, significantly enhancing coverage efficiency. Experimental and simulation results demonstrate the advantage of the aGBNN approach, in terms of path length, and total time to complete area coverage compared to state-of-the-art methods. © 2004-2012 IEEE.

关键词： Robot programming

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Fast Surface Error Diagnosis for Radiotelescopes Using Linearized Microwave Holography

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IEEE Transactions on Antennas and Propagation 2025年

作者： Romero, Celia Fonta Varela, Fernando Rodriguez Iraguen, Belen Galocha Lopez-Perez, Jose-Antonio Universidad Politécnica de Madrid Information Processing and Telecommunications Center Radiation Group Department of Signals Systems and Radiocommunications MadridE-28040 Spain Universidad Rey Juan Carlos Group of Microwave Engineering and Radiocommunication Systems Department of Signal Theory and Communications and Telematic Systems and Computing MadridE-28942 Spain Centro Astronómico de Yebes Dirección General del Instituto Geográfico Nacional Guadalajara19001 Spain

Radiotelescopes are typically composed of large reflector antennas located outdoors. These antennas are designed to achieve high levels of gain, which is possible due to their large size and RF systems designed for working at high frequencies. However, various sources of error (such as mounting imperfection or deformations caused by gravity and weather effects) are difficult to identify and can significantly degrade the performance of the radiotelescope, reducing its gain. The correct diagnosis of these errors has been a challenge in radioastronomy. The most widely used technique is microwave holography, in which mechanical errors are detected through long electromagnetic acquisitions. The measured far-field is processed to obtain the aperture field and thus the errors affecting the surface or the phase distribution. In this paper, a novel methodology is proposed to diagnose reflector errors using holography. The proposed approach defines a system that models all possible aperture errors as a combination of basis functions, directly relating the errors to the acquired far-field and reducing the number of samples required for analysis. © 1963-2012 IEEE.

关键词： Reflection

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A BAYESIAN-APPROACH TO THE RESTORATION OF DEGRADED AUDIO signalS

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IEEE TRANSACTIONS ON SPEECH AND AUDIO processing 1995年第4期3卷 267-278页

作者： GODSILL, SJ RAYNER, PJW Signal Processing and Communications Group Engineering Department University of Cambridge Cambridge UK

In this paper we derive the a posteriori probability for the location of bursts of noise additively superimposed on a Gaussian AR process. The theory is developed to give a sequentially based restoration algorithm suitable for real-time applications. The algorithm is particularly appropriate for digital audio restoration, where clicks and scratches may be modelled as additive bursts of noise. Experiments are carried out on both real audio data and synthetic AR processes and significant improvements are demonstrated over existing restoration techniques.

关键词： Bayesian methods signal restoration Degradation Audio recording Acoustic noise signal processing CD recording Additive noise Digital recording Noise level

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FAST INTERPOLATION BY FFT WITH GREATLY INCREASED ACCURACY

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ELECTRONICS LETTERS 1993年第13期29卷 1200-1201页

作者： MACLEOD, MD Signal Processing and Communications Group Engineering Department Cambridge University Cambridge UK

When the FFT (or DCT or DST) is used for fast interpolation, errors arise due to the assumed periodicity in the data, and the resulting implied discontinuities of the function and its derivatives at the block edges. By adding simple functions before interpolation and subtracting them again afterwards, these interpolation errors can be removed.

关键词： FOURIER TRANSFORMS TRANSFORMS

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NONLINEAR RECURSIVE SMOOTHING FILTERS AND THEIR USE FOR NOISE FLOOR ESTIMATION

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ELECTRONICS LETTERS 1992年第21期28卷 1952-1953页

作者： MACLEOD, MD Signal Processing and Communications Group Engineering Department Cambridge University Cambridge UK

Nonlinear recursive (NLR) digital smoothing filters are introduced and their use for spectrum noise floor estimation described. NLR filters outperform linear filters, achieving comparable results to median filters. an... 详细信息

关键词： DIGITAL FILTERS FILTERS SPECTRUM ESTIMATION SMOOTHING CIRCUITS

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A NONCOHERENT CORRELATION TECHNIQUE AND FOCUSED BEAMFORMING FOR ULTRASONIC UNDERWATER IMAGING - A COMPARATIVE-ANALYSIS

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IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL 1994年第5期41卷 621-630页

作者： MURINO, V REGAZZONI, CS TRUCCO, A VERNAZZA, G Signal Processing and Understanding Group Department of Biophysical and Electronic Engineering University of Genoa Genoa Italy

The purpose of this paper is to describe a noncoherent correlation technique for the formation of 3-D acoustic images, mainly for underwater applications. This technique is applied to the envelope of signals received by a 2-D array. The performances of the technique are compared with those of the coherent technique of focused beamforming in terms of angular resolution, depth of field, beam pattern, and accuracy in range determination. Moreover, special attention is given to the modalities for an efficient implementation on a digital computer. The complete absence of grating lobes, for whatever arrangement of the transducers, and the much higher speed of the imaging process, as compared with that of beamforming in the time domain, are the two major advantages of this technique. A reduction in the speckle effect, the possibility of creating a virtual depth of field, the feasibility of using square-law transducers, and the implementation simplicity are additional interesting characteristics. The results of some simulations are reported and compared with those obtained by the beamforming process.

关键词： Array signal processing Focusing Transducers Acoustic applications Underwater acoustics signal resolution Acoustic beams Gratings High-resolution imaging Speckle

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