scholarly journals De-Noising Process in Room Impulse Response with Generalized Spectral Subtraction

2021 ◽  
Vol 11 (15) ◽  
pp. 6858
Author(s):  
Min Chen ◽  
Chang-Myung Lee
Keyword(s):  
Noise Reduction ◽  
Impulse Response ◽  
Dynamic Range ◽  
Evaluation Criteria ◽  
Control Measures ◽  
Spectral Subtraction ◽  
Artificial Noise ◽  
Estimation Errors ◽  
Noise Compensation ◽  
Compensation Methods

The generalized spectral subtraction algorithm (GBSS), which has extraordinary ability in background noise reduction, is historically one of the first approaches used for speech enhancement and dereverberation. However, the algorithm has not been applied to de-noise the room impulse response (RIR) to extend the reverberation decay range. The application of the GBSS algorithm in this study is stated as an optimization problem, that is, subtracting the noise level from the RIR while maintaining the signal quality. The optimization process conducted in the measurements of the RIRs with artificial noise and natural ambient noise aims to determine the optimal sets of factors to achieve the best noise reduction results regarding the largest dynamic range improvement. The optimal factors are set variables determined by the estimated SNRs of the RIRs filtered in the octave band. The acoustic parameters, the reverberation time (RT), and early decay time (EDT), and the dynamic range improvement of the energy decay curve were used as control measures and evaluation criteria to ensure the reliability of the algorithm. The de-noising results were compared with noise compensation methods. With the achieved optimal factors, the GBSS contributes to a significant effect in terms of dynamic range improvement and decreases the estimation errors in the RTs caused by noise levels.

Performance Improvement of Digital Hearing Aid Systems

2015 ◽  
Vol 1 ◽  
pp. 27
Author(s):  
Isiaka Ajewale Alimi
Keyword(s):  
Noise Reduction ◽  
Hearing Aids ◽  
Digital Signal Processor ◽  
Speech Intelligibility ◽  
Communication Systems ◽  
Hearing Aid ◽  
Spectral Subtraction ◽  
Residual Spectrum ◽  
Digital Hearing Aids ◽  
Digital Hearing Aid

Digital hearing aids addresses the issues of noise and speech intelligibility that is associated with the analogue types. One of the main functions of the digital signal processor (DSP) of digital hearing aid systems is noise reduction which can be achieved by speech enhancement algorithms which in turn improve system performance and flexibility. However, studies have shown that the quality of experience (QoE) with some of the current hearing aids is not up to expectation in a noisy environment due to interfering sound, background noise and reverberation. It is also suggested that noise reduction features of the DSP can be further improved accordingly. Recently, we proposed an adaptive spectral subtraction algorithm to enhance the performance of communication systems and address the issue of associated musical noise generated by the conventional spectral subtraction algorithm. The effectiveness of the algorithm has been confirmed by different objective and subjective evaluations. In this study, an adaptive spectral subtraction algorithm is implemented using the noise-estimation algorithm for highly non-stationary noisy environments instead of the voice activity detection (VAD) employed in our previous work due to its effectiveness. Also, signal to residual spectrum ratio (SR) is implemented in order to control the amplification distortion for speech intelligibility improvement. The results show that the proposed scheme gives comparatively better performance and can be easily employed in digital hearing aid system for improving speech quality and intelligibility.

scholarly journals Regional robust secure precise wireless transmission design for multi-user UAV broadcasting system

2020 ◽  
Vol 2020 (1) ◽  
Author(s):  
Tong Shen ◽  
Tingting Liu ◽  
Yan Lin ◽  
Yongpeng Wu ◽  
Feng Shu ◽  
...  
Keyword(s):  
Estimation Error ◽  
Wireless Transmission ◽  
Artificial Noise ◽  
Target Area ◽  
Secrecy Rate ◽  
Estimation Errors ◽  
Transmission Design ◽  
Broadcasting System ◽  
Aerial Vehicle ◽  
Noise Ratio

Abstract In this paper, two regional robust secure precise wireless transmission (SPWT) schemes for multi-user unmanned aerial vehicle (UAV), (1)regional signal-to-leakage-and-noise ratio (SLNR) and artificial-noise-to-leakage-and-noise ratio (ANLNR) (R-SLNR-ANLNR) maximization and (2) point SLNR and ANLNR (P-SLNR-ANLNR) maximization, are proposed to tackle with the estimation errors of the target users’ location. In the SPWT system, the estimation error for SPWT cannot be ignored. However, the conventional robust methods in secure wireless communications optimize the beamforming vector in the desired positions only in statistical means and cannot guarantee the security for each symbol. The proposed regional robust schemes are designed for optimizing the secrecy performance in the whole error region around the estimated location. Specifically, with the known maximal estimation error, we define the target region and wiretap region. Then, we design an optimal beamforming vector and an artificial noise projection matrix, which achieve the confidential signal in the target area having the maximal power while only few signal power is conserved in the potential wiretap region. Instead of considering the statistical distributions of the estimated errors into optimization, we optimize the SLNR and ANLNR of the whole target area, which significantly decreases the complexity. Moreover, the proposed schemes can ensure that the desired users are located in the optimized region, which are more practical than the conventional methods. Simulation results show that our proposed regional robust SPWT design is capable of substantially improving the secrecy rate compared to the conventional non-robust method. The P-SLNR-ANLNR maximization-based method has the comparable secrecy performance with lower complexity than that of the R-SLNR-ANLNR maximization-based method.

Timing performance of large area SiPMs coupled to LYSO using dark noise compensation methods

2011 ◽  
Author(s):  
Claudio Piemonte ◽  
Alberto Gola ◽  
Antonio Picciotto ◽  
Tiziana Pro ◽  
Nicola Serra ◽  
...  
Keyword(s):  
Large Area ◽  
Dark Noise ◽  
Noise Compensation ◽  
Compensation Methods

SFDR Improvement Algorithms for Current-Steering DACs

2015 ◽  
Vol 643 ◽  
pp. 101-108 ◽  
Author(s):  
Shaiful Nizam Mohyar ◽  
Masahiro Murakami ◽  
Atsushi Motozawa ◽  
Haruo Kobayashi ◽  
Osamu Kobayashi ◽  
...  
Keyword(s):  
Dynamic Range ◽  
Current Source ◽  
Weighted Averaging ◽  
Current Steering ◽  
Switching Sequence ◽  
Digital To Analog Converters ◽  
Compensation Methods ◽  
Spurious Free Dynamic Range ◽  
Data Weighted Averaging ◽  
Combined Algorithm

This paper presents algorithms for improving spurious-free dynamic range (SFDR) of current-steering digital-to-analog converters (DACs) — targeted at communication applications — by minimizing both current-source mismatches and glitches. Conventional segmented current-steering DACs suffer from static mismatches among current sources which cause nonlinearity and degrade SFDR, though glitch energy is relatively small. The data-weighted averaging (DWA) algorithm can reduce static current source mismatch effects, but it increases the effects of glitch energy. Here we investigate the use of both conventional Switching-Sequence Post-Adjustment (SSPA) calibration and One–Element-Shifting (OES) methods in order to reduce the effects of both nonlinearity and glitch energy. For further improvement, we propose and investigate a fully-digital combined algorithm to reduce static current source mismatch effects with minimal increase in the glitch energy. We also did simulations of the effect of combining these two compensation methods. Our MATLAB simulations show that the combined algorithm can improve SFDR performance by 24 dB, 22dB and 2dB compared to conventional thermometer-coded, one-element-shifting and SSPA methods respectively in some conditions. When we take current mismatch into account, the combined algorithm causes glitch energy to increase by only 0.02 to 0.2 % compared to the other three methods alone.

Design and evaluation of a high-performance haptic interface

Robotica ◽  
1996 ◽  
Vol 14 (3) ◽  
pp. 321-327 ◽  
Author(s):  
R.E. Ellis ◽  
O.M. Ismaeil ◽  
M.G. Lipsett
Keyword(s):  
High Performance ◽  
Dynamic Range ◽  
Evaluation Criteria ◽  
Haptic Interface ◽  
Human Operator ◽  
Haptic Interfaces ◽  
Environment Design ◽  
Mechanical Constraints ◽  
Computer Controlled ◽  
The Many

SUMMARYA haptic interface is a computer-controlled mechanism designed to detect motion of a human operator without impeding that motion, and to feed back forces from a teleoperated robot or virtual environment. Design of such a device is not trivial, because of the many conflicting constraints the designer must face.As part of our research into haptics, we have developed a prototype planar mechanism. It has low apparent mass and damping, high structural stiffness, high force bandwidth, high force dynamic range, and an absence of mechanical singularities within its workspace. We present an analysis of the human-operator and mechanical constraints that apply to any such device, and propose methods for the evaluation of haptic interfaces. Our evaluation criteria are derived from the original task analysis, and are a first step towards a replicable methodology for comparing the performance of different devices.

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