Amin Saremi | Linköping University (original) (raw)

Papers by Amin Saremi

Remote Sensing of Clouds and the Atmosphere XXVIII

EURASIP Journal on Audio, Speech, and Music Processing

Acoustic echo cancelation (AEC) is a system identification problem that has been addressed by var... more Acoustic echo cancelation (AEC) is a system identification problem that has been addressed by various techniques and most commonly by normalized least mean square (NLMS) adaptive algorithms. However, performing a successful AEC in large commercial vehicles has proved complicated due to the size and challenging variations in the acoustic characteristics of their cabins. Here, we present a wideband fully linear time domain NLMS algorithm for AEC that is enhanced by a statistical double-talk detector (DTD) and a voice activity detector (VAD). The proposed solution was tested in four main Volvo truck models, with various cabin geometries, using standard Swedish hearing-in-noise (HINT) sentences in the presence and absence of engine noise. The results show that the proposed solution achieves a high echo return loss enhancement (ERLE) of at least 25 dB with a fast convergence time, fulfilling ITU G.168 requirements. The presented solution was particularly developed to provide a practical ...

How differently noise exposure and metabolic presbyacusis affect the cochlear response. A simulat... more How differently noise exposure and metabolic presbyacusis affect the cochlear response. A simulation approach using a physiologically-based model of the human cochlea

Objective: This study includes a battery of psychoacoustical and electrophysiological tests to qu... more Objective: This study includes a battery of psychoacoustical and electrophysiological tests to quantitatively investigate the changes in the frequency and the temporal features of the human auditor ...

A physiologically-based electromechanical model of the human cochlea is used in this study to exp... more A physiologically-based electromechanical model of the human cochlea is used in this study to explicitly simulate the effects of acoustical overstimulation, and the associated cellular deficiencies ...

$Research paper thumbnail of Temperature Sensing in Space and Transparent Media: Advancements in Off-Axis Digital Holography and the Temperature Coefficient of Refractive Index$

Applied Sciences

An off-axis digital holographic interferometry technique integrated with a Mach–Zehnder interfero... more An off-axis digital holographic interferometry technique integrated with a Mach–Zehnder interferometer based setup is demonstrated for measuring the temperature and temperature profile of a transparent medium. This technique offers several advantages: it does not require precise optomechanical adjustments or accurate definition of the frequency carrier mask, making it simple and cost-effective. Additionally, high-quality optics are not necessary. The methodology relies on measuring the phase difference between two digitally reconstructed complex wave fields and utilizing the temperature coefficient of the refractive index. In this way, we presented an equation of the temperature as a function of phase changes and the temperature coefficient of refractive index. This approach simplifies the calculation process and avoids the burden of complicated mathematical inversions, such as the inverse Abel transformation. It also eliminates the need for additional work with the Lorentz–Lorentz ...

Journal of Signal Processing Systems

In an open world with a long-tail distribution of input samples, Deep Neural Networks (DNNs) may ... more In an open world with a long-tail distribution of input samples, Deep Neural Networks (DNNs) may make unpredictable mistakes for Out-of-Distribution (OOD) inputs at test time, despite high levels of accuracy obtained during model training. OOD detection can be an effective runtime assurance mechanism for safe deployment of machine learning algorithms in safety–critical applications such as medical imaging and autonomous driving. A large number of OOD detection algorithms have been proposed in recent years, with a wide range of performance metrics in terms of accuracy and execution time. For real-time safety–critical applications, e.g., autonomous driving, timing performance is of great importance in addition to accuracy. We perform a comprehensive and systematic benchmark study of multiple OOD detection algorithms in terms of both accuracy and execution time on different hardware platforms, including a powerful workstation and a resource-constrained embedded device, equipped with bo...

Advances in Fundamental and Applied Research on Spatial Audio

Since the introduction of hands-free telephony applications and speech dialog systems in automoti... more Since the introduction of hands-free telephony applications and speech dialog systems in automotive industry in 1990s, microphones have been mounted in car cabins to capture, and route the driver’s speech signals to the corresponding telecommunication networks. A car cabin is a noisy and reverberant environment where engine activity, structural vibrations, road bumps, and cross-talk interferences can add substantial amounts of acoustic noise to the captured speech signal. To enhance the speech signal, a variety of real-time signal enhancement methods such as acoustic echo cancelation, noise reduction, de-reverberation, and beamforming are typically applied. Moreover, the recent introduction of AI-driven online voice assistants in automotive industry has resulted in new requirements on speech signal enhancement methods to facilitate accurate speech recognition. In this chapter, we focus on spatial filtering techniques that are designed to spatially enhance signals that arrive from ce...

International Journal for Numerical Methods in Biomedical Engineering, 2022

A biophysically-inspired signal processing model of the human cochlea is deployed to simulate the... more A biophysically-inspired signal processing model of the human cochlea is deployed to simulate the effects of specific noise-induced inner hair cell (IHC) and outer hair cell (OHC) lesions on hearing thresholds, cochlear compression, and the spectral and temporal features of the auditory nerve (AN) coding. The model predictions were evaluated by comparison with corresponding data from animal studies as well as human clinical observations. The hearing thresholds were simulated for specific OHC and IHC damages and the cochlear nonlinearity was assessed at 0.5 and 4 kHz. The tuning curves were estimated at 1 kHz and the contributions of the OHC and IHC pathologies to the tuning curve were distinguished by the model. Furthermore, the phase locking of AN spikes were simulated in quiet and in presence of noise. The model predicts that the phase locking drastically deteriorates in noise indicating the disturbing effect of background noise on the temporal coding in case of hearing impairment. Moreover, the paper presents an example wherein the model is inversely configured for diagnostic purposes using a machine learning optimization technique (Nelder-Mead method). Accordingly, the model finds a specific pattern of OHC lesions that gives the audiometric hearing loss measured in a group of noise-induced hearing impaired humans. Significance: The model is capable of closely reproducing the corresponding experimental data and also diagnosing the underlying biophysical origins of an observed hearing loss. The MATLAB source codes developed in this work are publicly available to enable researchers to simulate various types and configurations of cochlear lesions. This article is protected by copyright. All rights reserved.

Gated auditory speech perception: effects of listening

Simulation of presbyacusis by a physiological signal transmission model of the human cochlea

Canadian Acoustics, 2015

The Stria Vascularis regulates the electrical potentials inside the mammalian cochlea that are vi... more The Stria Vascularis regulates the electrical potentials inside the mammalian cochlea that are vital for the optimal operation of the ‘cochlear amplifier’. The effects of the age-related deficits of the endocochlear potential (EP) on the outer hair cell (OHC) motile forces have been investigated both theoretically and experimentally. Nevertheless, it is much less known how the age-related EP reduction explicitly affects the sensory inner hair cells (IHCs). This study analyzes the effects of the EP reduction on the IHC membrane potential and thereby the auditory nerve (AN) neurotransmitter release rate. This numerical analysis is performed using a biophysical lumped-element model of the IHC [Lopez-Poveda and Eustaque-Martin, JARO.7, 218-235 (2006)] and a computational model of the human AN [Zilany et al ., J. Acoust. Soc. Am.135, 283-286 (2014)] for frequencies from 0.25 to 6 kHz. The hearing threshold was defined as the minimum displacement of the IHC stereocilia which generates a f...

The Journal of the Acoustical Society of America, 2018

The cascade of asymmetric resonators with fast-acting compression (CARFAC) is a cascade filterban... more The cascade of asymmetric resonators with fast-acting compression (CARFAC) is a cascade filterbank model that performed well in a comparative study of cochlear models, but exhibited two anomalies in its frequency response and excitation pattern. It is shown here that the underlying reason is CARFAC's inclusion of quadratic distortion, which generates DC and low-frequency components that in a real cochlea would be canceled by reflections at the helicotrema, but since cascade filterbanks lack the reflection mechanism, these low-frequency components cause the observed anomalies. The simulations demonstrate that the anomalies disappear when the model's quadratic distortion parameter is zeroed, while other successful features of the model remain intact.

The Journal of the Acoustical Society of America, Sep 1, 2016

Auditory models have been developed for decades to simulate characteristics of the human auditory... more Auditory models have been developed for decades to simulate characteristics of the human auditory system, but it is often unknown how well auditory models compare to each other or perform in tasks they were not primarily designed for. This study systematically analyzes predictions of seven publicly-available cochlear filter models in response to a fixed set of stimuli to assess their capabilities of reproducing key aspects of human cochlear mechanics. The following features were assessed at frequencies of 0.5, 1, 2, 4, and 8 kHz: cochlear excitation patterns, nonlinear response growth, frequency selectivity, group delays, signal-in-noise processing, and amplitude modulation representation. For each task, the simulations were compared to available physiological data recorded in guinea pigs and gerbils as well as to human psychoacoustics data. The presented results provide application-oriented users with comprehensive information on the advantages, limitations and computation costs of...

AIP Conference Proceedings, 2015

The bottom-up signal pathway, which starts from the outer ear and leads to the brain cortices, gi... more The bottom-up signal pathway, which starts from the outer ear and leads to the brain cortices, gives the classic image of the human sound perception. However, there have been growing evidences in the last six decades for existence of a functional descending network whereby the central auditory system can modulate the early auditory processing, in a top-down manner. The medial olivocochlear efferent fibers project from the superior olivary complex at the brainstem into the inner ear. They are linked to the basal poles of the hair cells by forming synaptic cisterns. This descending network can activate nicotinic cholinergic receptors (nAChR) that increase the membrane conductance of the outer hair cells and thereby modify the magnitude of the active force generated inside the cochlea. The aim of the presented work is to quantitatively investigate how the changes in the biomechanics of the outer hair cells, caused by the efferent activation, manipulate the cochlear responses. This is done by means of a frequency-domain biophysical model of the cochlea [12] where the parameters of the model convey physiological interpretations of the human cochlear structures. The simulations manifest that a doubling of the outer hair cell conductance, due to efferent activation, leads to a frequency-dependent gain reduction along the cochlear duct with its highest effect at frequencies between 1 kHz and 3.5 kHz and a maximum of approximately 10 dB gain reduction at 2 kHz. This amount of the gain inhibition and its frequency dependence reasonably agrees with the experimental data recorded from guinea pig, cat and human cochleae where the medial olivococlear efferents had been elicited by broad-band stimuli. The simulations also indicate that the efferent-induced increase of the outer hair cell conductance increases the best frequency of the cochlear responses, in the basal region. The presented simulations quantitatively confirm that activation of the medial olivocochlear efferents can biomechanically manipulate the cochlear responses, in a top-down manner, by inhibiting the gain of the cochlear amplifier as well as altering the frequency-position map (tuning pattern) of the cochlea.

Canadian Acoustics, Sep 1, 2012

2009 Third UKSim European Symposium on Computer Modeling and Simulation, 2009

The role of context for better decision-making has been a topic of significant research effort ov... more The role of context for better decision-making has been a topic of significant research effort over the years. Context-aware systems are able to adapt their operations to the current context without explicit user intervention and thus aim at increasing usability and effectiveness by taking environmental context into account. These systems exploit information about the context of use, such as the