gammatone filter cochlear model

Folded Architecture for Digital Gammatone Filter Used in ... 131, no. Based on the work of Roy Patterson and John Holdsworth, a good fit for this data is provided by a Gammatone function. The Gammatone Auditory Filterbank - CNBH Acoustic Scale Wiki This auditory front-end combines a Gammatone filter bank with a model of hair cell dynamics proposed by Ray Meddis. [PDF] An Efficient Implementation of the Patterson ... 2.1. Example: sound_localisation_model (hears)¶ Example demonstrating the use of many features of Brian hears, including HRTFs, restructuring filters and integration with Brian. Three different auditory representations—Lyon's cochlear model, Patterson's gammatone filter bank combined with Meddis' inner hair cell model, and mel-frequency cepstral coefficients—are analyzed in connection with self-organizing maps to evaluate their suitability for a perceptually justified classification of sounds. The presented level-dependent parameterization of All-Pole (APGTF) and One-Zero (OZGTF) gammatone filters is derived from Slaney's implementation [18] of a cochlear model proposed by Patterson [19]. To give an idea of how this tool facilitates auditory modeling and the integration with neural modeling, Figure 1 shows an auditory model consisting of a gammatone filterbank with half-wave rectification, compression, and spiking with integrate-and-fire models (but note that the toolbox can also be used independently of Brian). In . It uses a causal impulse response function to describe the characteristics of the filter. approaches to speech analysis and with a simpler auditory model from a wavelet-ﬂlterbank perspective. It provides a simple linear filter , which is therefore easy to implement, but cannot by itself account for nonlinear aspects of the auditory system; it is nevertheless used in a variety of models of the auditory system . US20060072766A1 - Reverberation removal - Google Patents A bandpass filter, as used in auditory modeling; approximates the frequency selectivity of a haircell site on the basilar membrane in the cochlea. Frontiers | Brian Hears: Online Auditory Processing Using ... The bandwidth of each gammatone filter increases with increasing frequency so that a high centre frequency filter has a higher bandwidth than a filter with low centre frequency as shown in Figure 1(a). In using a gammatone filterbank model for cochlear filtering it is suggested to design a filterbank using Make_GTbank routine (see below) in advance, store the filter coefficients into a .mat-file, and then define the cochlea field in the following way: An essential processing step in any cochlear implant is. Folded Architecture for Digital Gammatone Filter Used in ... Study on modulation spectrum feature extraction of ship ... The filters are tonotopically organized from high frequencies at the base of the cochlea, to low frequencies at the . Both digital digital gammatone filter bank is implemented using the filters were designed using the bilinear transform . The impulse response of a Gammatone filter centered at frequency f is: 12cos(2 ), 0 (,) 0, te ft tabt gft else ° = ® °¯. Noise Reduction in Acoustic Signals Using a Cochlear Model [13] Strahl, S. and Mertins, A., Analysis and design of gammatone signal models. Zero Gammatone Filter (OZGF) is presented together with its automatic gain control that models its level-dependent nonlinear behaviour. PDF An Auditory-based Feature for Robust Speech Recognition Ngamkham W, Sawigun C, Hiseni S, Serdijn WA (2010) Analog complex Gammatone filter for cochlear implant channels, pp 969-972 27. PDF An Efficient Implementation of the Patterson-Holdsworth ... 5, pp. Both Mel and Gammatone spectrograms are computed based on the STFT . To encompass the entire hearing range and to take into account common audio standards, the sampling rate is set to f s = 44,1 kHz. This paper describes a 16-channel non-uniformly spaced, high stop band attenuation (≅ -60dB) finite impulse response (FIR) filter bank model for cochlear implants and how speech intelligibility . In psychoacoustic modelling, two different approaches have been followed over the years. It can simulate the band-pass filter characteristics of the basement membrane. Journal of the Acoustical Society of America 2001,110(6):3107-3118. It implements a fitlerbank of IIR gammatone filters as described in Slaney, M., 1993, "An Efficient Implementation of the Patterson-Holdsworth Auditory Filter Bank". The gammatone impulse response is given by where (in Hz) is the center frequency, (in radians) is the phase of the carrier, is the amplitude, through a bank of fourth-order gammatone filters [29], which is a standard model for cochlear filtering. The impulse response of a gammatone lter centered at frequency f is: g(f,t)= The asymmetric function is excellently simulated with a minimum-phase IIR filter, named the "asymmetric compensation filter". (1) 10.1121/1.1416197. Specifically, a Gammatone feature (GF) is obtained from a bank of Gammatone filters, which was originally proposed to model human cochlear filtering. Digital implementations of linear gammatone filters are regularly part of auditory models and can be used in the sound processing in cochlear implants. Four different filters were implemented in an established model of CI hearing, the tone-excited vocoder, namely: GTF (Gammatone Filter), DAPGF (Differentiated All-Pole GTF), OZGF (One-Zero GTF) and BUTF (Butterworth). US20060072766A1 US10/959,408 US95940804A US2006072766A1 US 20060072766 A1 US20060072766 A1 US 20060072766A1 US 95940804 A US95940804 A US 95940804A US 2006072766 A1 US2006072766 A1 US 2006072766A1 Authority US United States Prior art keywords audio signal reverberation signal spectro band Prior art date 2004-10-05 Legal status (The legal status is an assumption and is not a legal conclusion. Gammatone Filter Bank The Gammatone filter bank is a standard cochlear auditory filter [ 29 , 30 ]. Gammatone filters¶ Example of the use of the class Gammatone available in the library. The bandwidth of each filter is set according to its equivalent rectangular bandwidth (ERB) and we use a bank of 128 gammatone filters with center frequencies equally distributedon the ERB scale between 80Hz and 5 kHz [5], [39]. Cochleagram analysis is a powerful tool to investigate musical noise. And then GFCC of original voice and distorted voice are calculated to find out the average distortion distance, and the mapping relationship between subjective MOS and normalized average distortion distance is established. candidate for asymmetric, level-dependent auditory filters. 2.2. The number of the filter channels is 64, with center frequencies spaced from 50 Hz to 8000 Hz. The asymmetric function is excellently simulated with a minimum-phase IIR filter, named the "asymmetric compensation filter". Cochlear models can be divided into two classes: transmission-lines (TL) and auditory filterbanks (Duifhuis, 2004).The TL models represent the cochlea partition as a coupled mass-spring-damper system to model wave propagation on the Basilar Membrane (BM) (Zweig et al., 1976).TL models are faithful to the physiology and are accurate in simulating wave propagation on the BM. We review several lines of develop- Cochlear filterbank Gammachirp and Gammatone filterbanks as typical cochlear filterbanks model the basilar membrane motion well. The auditory filter may be considered as a weighting function representing frequency selectivity at a particular centre frequency. Gammatone filters. 2.0 Ear Filters Patterson's cochlear model is based on an array of independent bandpass filters. Implements a simplified version of the "ideal" sound localisation model from Goodman and Brette (2010). Fig . Auditory Filterbank The filtering action of the basilar membrane is simulated as a bank of 512 gammatone filters which model the shape, bandwidth and centre frequencies from studies of . The auditory models generate the neuron firing signals called the cochleagram. This auditory model is implemented using the MakeERBFilters, ERBFilterBank , and MeddisHairCell commands. Thus, the Gammatone filter bank is widely adopted as the cochlear basement membrane model. This paper simulates the processing mechanism of the cochlear and the practical characteristics of ship radiated noise signals according to the integrated Gammatone auditory filter and the Meddis internal hair cell model, and it builds a Gamatone-Meddis auditory periphery model that is suitable for ship radiated noise signals. Its name is due to the nature of its impulse response, which is a gamma envelope modulated by a tone carrier centered at f c Hz [7] . Like a previous report [Slaney1988], this document is an electronic notebook . The Gamma-Tone Filter (GTF), introduced by Johannesma to describe cochlear nucleus response in 1972 [J72] and previously used as a basilar membrane model by Flanagan in 1960 [F60], has been adopted as the basis of a number of successful auditory modeling efforts [F62a, S85, P94, MH91, AS89]. Its shape can be derived using the power-spectrum model of masking which assumes: (1) in detecting a signal in a masker the observer uses the single auditory filter giving the highest signal-to-masker ratio; (2) threshold corresponds to a fixed signal-to-masker . For this purpose, the corrupted signal is decomposed into a number of sub-bands using complex Gammatone filter bank, and the sub . Gammatone filters There is a whole field of research devoted to cochlear modelling. The filter is a combination of a shaping filter above 1kHz and a high-pass filter below 1kHz, and was developed from the model designed by Martin Pflueger et al. transfer function (HRTF) was used for the outer ear model and gammatone filter bank model for the cochlear. We find that such features achieve Gammatone filtering models the cochlea by a bank of overlapping bandpass filters mimicking the structure of the peripheral auditory processing stage. Initially, the gammachirp filter is shown to be decomposed into a combination of a gammatone filter and an asymmetric function. 3.0 Gammatone Filters Roy Patterson's ear model is based on impulse responses of the form n - 1 Fig.2 (a) Modified gammatone filter banks based on Glasberg and Moore parameters (1990), EarQ =10 (b) Equivalent rectangular bandwidth (ERB) 2.2.2 Acoustic fovea modelling The narrowband filters are designed to reconstruct the processing in the acoustic fovea of the cochlear of CF bats. CiteSeerX - Document Details (Isaac Councill, Lee Giles, Pradeep Teregowda): Abstract — Auditory filter models have a history of over a hundred years, with explicit bio-mimetic inspiration at many stages along the way. Soc. psychology, and neurophysiology. and uses the activated dictionary atoms to create a time-varying filter to enhance the noisy speech. For the 20 kHz carrier frequency of the echolocating signal Gammatone filter banks Derived from psychophysical observations of the auditory periphery, the gammatone filter is a standard cochlea auditory filter. [2] The gammatoneFilterBank follows the algorithm described in [1]. From passive analogue electric delay line models, through digital filter models, active analogue VLSI models, and abstract filter shape models, these filters have both . The characteristic of the Gammatone filter bank is highly consistent with the auditory characteristic which can well simulate the basement membrane frequency selectivity and spectral analysis characteristics. Second, we propose a framework for incorporating the . A Gammatone filterbank which was introduced by Johannsma (1972) for the peripheral filtering in the cochlea and estimated by the reverse correlation function of neural firing times can be used for the frequency decomposition of the acoustic signal in hearing devices ( Holdsworth et al., 1988 ). 2. The gammatone is a linear filter and the magnitude characteristic is approximately symmetric on a linear frequency scale. The self-organizing maps are trained with a uniform set of test . The elevation and azimuth were then estimated by a neural network using IID's and ITD's. The neural network complemented by This notebook describes a new efficient implementation and includes C, Fortran, and Matlab implementations. To encompass the entire hearing range and to take into account common audio standards, the sampling rate is set to f, = 44,1 kHz. the basis of a number of successful auditory modeling efforts. Roy Patterson has proposed a model of psychoacoustic filtering based on critical bands. This notebook depends on the filter design functions contained in the . Gammatone lters are derived from psy-chophysical observations of the auditory periphery and this lter-bank is a standard model of cochlear ltering [17]. coded following: V Hohmann Frequency analysis and synthesis using a Gammatone filterbank Acta Acustica vol 88 (2002): 433--442. IID and ITD were extracted by subtracting and cross correlating the outputs from the both side cochlea. Previous work is extended by deriving an even more efficient implementation of the Gammatone filter bank, and by showing the MATLAB™ code to design and implement an ERB filter bank based on Gamm atone filters. produced by the auditory wavelet-like transforms produced by the gammatone and gammachirp ﬂlters. The Gammatone Filter, is one such filter. Block diagram of cochlear model used to extract the signal envelope in each auditory band . The transmission line cochlear models (Ambikairajah et al., 1989) which closely model the cochlea mechanics have the inherent advantage of reproducing the observed auditory filter shapes as illustrated in Fig. Cochleagram analysis is a powerful tool to investigate musical noise. Article Google Scholar 44. van Immerseel L, Peeters S: Digital implementation of linear gammatone filters: comparison of design methods. Time t is . Am., vol. Hence, the Gammachirp filter is used in this study. 1, which is compared against gammatone auditory filter.It is clear from the figure that the transmission line cochlear model has a very sharp frequency tuning compared with a gammatone . The impulse response of the gammatone is g tðtÞ¼atn 1 expð 2 bERB Nðf cÞtÞcosð2 f ct þ Þð1Þ where a, b, n, f c, and are parameters. Many people doing work with auditory perception use a simple linear model based on critical bands. Noise reduction in acoustic signals using a cochlear model Thesis submitted in partial fulfilment of the requirements of the University of London for the Degree of Master of Science Angeliki Bazigou August 2014 Department of Electronic Engineering and Computer Science, Queen Mary, University of London f I certify that this thesis, and the . Auditory models, such as the gammatone filter bank and the Meddis inner hair cell model, have been developed to simulate the acoustic to neuron transduction process. Then, This report describes an implementation of a cochlear model proposed by Roy Patterson [Patterson1992]. In this article, a human nonlinear filterbank is constructed by adapting a computational model of animal BM physiology to simulate human BM nonlinearity as measured by psychophysical pulsation-threshold . The aim can be to better understand the structure of the cochlea described above, by accurate mechanical modelling, or to reproduce its signal processing characteristics on a functional level. The PZFC analog cochlear model (Lyon and Mead, 1988) and the CAR-FAC model are such examples. A gammatone filter behaves like a bandpass filter. The auditory models generate the neuron ﬂring signals called the cochleagram. Gammatone filters Gabor feature processor Spectro-temporal modulation spectrogram (STMS) Neuron rate maps M. R. Schädler et al., "Spectro-temporal modulation subspace-spanning filter bank features for robust automatic speech recognition," J. Acoust. This paper uses the gammatone filter bank [ 9] to realize the cochlear model. Some published cochlear filterbanks are nonlinear but are fitted to animal basilar membrane (BM) responses. I. With gammatone filterbanks, the mixtures are This model consisted of a gammatone auditory filter bank that converted acoustic input into a multichannel representation of basilar membrane motion (27 . We review several lines of develop- The pass filter having a cutoff frequency of 5 kHz . Similar to the MFCC, the gammatone frequency cepstral coefficient (GFCC) is derived using gammatone filters with equivalent rectangular bandwidth bands (ERB) [47]. Approximate Gammatone filters Cochlear models Butterworth filters Artificial Vowels IIR filterbank Dual resonance nonlinear filter (DRNL) Time varying filter (1) Time varying filter (2) Sound localisation model Compressive Gammachirp filter (DCGC) Response area and phase response in the Tan&Carney model Spiking output of the Tan&Carney model A cochlear filterbank comprises multiple gammatone filters either in parallel or cascaded form. A standard model for T-F analysis in CASA system involves a bank of gammatone lters [24]. The design parameters for Gammatone function are introduced later in this document. The high correlation of this signal model with human speech and environmental sounds [E. Smith and M. Lewicki, Nature (London) 439, 978-982 (2006)], combined with the increased time-frequency resolution of sparse overcomplete signal models, makes the overcomplete gammatone . Google Scholar Cross Ref [14] Strahl, S. and Mertins, A., Sparse gammatone signal model optimized for English speech does not match the human auditory filters. The filter bandwidths are proportional to the auditory Equivalent Rectangular Bandwidth (ERB) function as described in [5], [6], [10]. It is a sufficient model in the spectral analysis of human speech signals at a moderate sound level, which makes it suitable to simulate the signal processing in the auditory system and for sound processing in the CI. Malcolm Slaney has coded each model with MATLAB so that given a signal input, the codes output a representation of hair cell responses. Its performance as speech recognition front-end was investigated in several papers and improvement over MFC baseline was demonstrated [ 36, 37, 38, 39 ]. Thus, the Gammatone filter bank is widely adopted as the cochlear basement membrane model. Gammatone filters are derived from psychophysical and physiological observations of the auditory periphery and this filterbank is a standard model of cochlear filtering [17]. The algorithm is an implementation of an idea proposed in [2]. candidate for asymmetric, level-dependent auditory filters. low or high tones were analyzed using a cochlear model to (i) determine frequencies that could be expected in the EEG re-sponse and (ii) estimate an early representation of the sound input. The gammatone filterbank could. INTRODUCTION Over about the last half century, many auditory ﬁlter models have been developed, analyzed, and applied to a variety of hearing-related problems. Magnitude frequency response of gammatone filters for normal . Motivations. Lopez-Poveda EA: A human nonlinear cochlear filterbank. Auditory filter models. Gammatone Filter Bank. Also shown in Figure 2 are two additional components of our complete auditory model: (1) Brain Research. The steps of the binaural model to calculate the result are the following (see also Dietz et al., 2011): Middle ear filtering (500-2000 Hz 1st order bandpass) Auditory bandpass filtering on the basilar membrane using a 4th-order all-pole gammatone filterbank, employing 23 filter bands between 200 and 5000 Hz, with a 1 ERB spacing. Gammatone sub-band magnitudedomain dereverberation for asr (2011) by K Kumar, R Singh, B Raj, R M Sterm . INTRODUCTION Over about the last half century, many auditory ﬁlter models have been developed, analyzed, and applied to a variety of hearing-related problems. A gammatone filter is a linear filter described by an impulse response that is the product of a gamma distribution and sinusoidal tone. . When the order of the filter is in the range 3-5, the shape of the magnitude characteristic of the gammatone filter is very similar to that of the roex(p) filter commonly used to represent the magnitude characteristic of the human auditory filter (Patterson and Moore, 1986). Fig . Auditory models, such as the gammatone ﬂlter bank and the Meddis inner hair cell model, have been developed to simulate the acoustic to neuron transduction process. Cochleagrams are obtained with a Gammatone filter bank, which is based on the cochlear model proposed in , which consists of an array of bandpass filters organized from high frequency at the base of the cochlea, to low frequencies at the apex (innermost part of the cochlea). The order of the gammatone filterbanks is 4 for usual implementation. These front-end components are illustrated in Figure 2 with the static gammatone filters, the level-dependent gammachip-filter rendition, and the hair cell model (to be subsequently discussed). The most commonly used auditory filter is the GTF, which provides the spectral analysis of the signals in the cochlea. 4134-4151, 2012. Gammatone filter bank that accords with human auditory system is used to extract characteristic parameters. The CAR-FAC model is a digital cascade auditory filter model proposed by Richard Lyon and described in detail in . Others, like the gammatone, are based on human psychophysical data, but are linear. The Gammatone Filter In time-domain auditory models, the spectral analysis performed by the basilar membrane is often simulated by a bank of gammatone auditory ﬁlters (e.g., [15]). • Cochlear filtering by the gammatone filterbank (or other models of cochlear filtering), followed by a stage of nonlinear rectification; the latter corresponds to hair cell transduction by either a hair cell model or simple compression operations (log and cube root) • Quasi-logarithmic frequency scale, and The presented level-dependent parameterization of All-Pule (APGTF) and One-Zero (OZGTF) gammatone filters is derived from Slancy's implementation [18] of a cochlear model proposed by Patterson [19]. absence of a compressive cochlear non-linear component, which is common to . It is a widely used model of auditory filters in the auditory system . Gammatone ( gammatoneProc.m) Dual-resonance non-linear filter bank ( drnlProc.m) One central processing element of the Auditory front-end is the separation of incoming acoustic signals into different spectral bands, as it happens in the human inner ear. Lei W, Yuan P, Lin ZQ, Jiang XH, Lin MU, Zhang FZ (2012) The application of computational auditory peripheral model in underwater target classification. we extend a previously proposed NMF-based technique for speech enhancement of noisy speech to exploit a Hidden Markov Model (HMM). v126. Initially, the gammachirp filter is shown to be decomposed into a combination of a gammatone filter and an asymmetric function. Gammatone filters [28]. It closely approximates the physiological elements that consist of the human cochlea and mimics its qualitative behavior. 1 . this was done using static auditory-like (gammatone) filters. Compared to the Gammatone filter, the Gammachirp filter is an asymmetric and nonlinear filter that has a similar shape to that of the cochlear filter [7]. How close digital impulse, magnitude, and phase responses match the corresponding properties of the analog gammatone filter is evaluated for one, finite-impulse response filter design, and for five, infinite-impulse response filter designs . An established model for the signal analysis performed by the human cochlea is the overcomplete gammatone filterbank. The gammatone auditory filterbank is particularly appropriate for simulating the cochlear filtering of broadband sounds like speech and music provided the sound level is in the broad middle range of hearing. US20060072766A1 US10/959,408 US95940804A US2006072766A1 US 20060072766 A1 US20060072766 A1 US 20060072766A1 US 95940804 A US95940804 A US 95940804A US 2006072766 A1 US2006072766 A1 US 2006072766A1 Authority US United States Prior art keywords audio signal reverberation signal spectro band Prior art date 2004-10-05 Legal status (The legal status is an assumption and is not a legal conclusion. Then, Gammatone frequency cepstral coefficients (GFCC) are derived from GF. In this paper, a gammatone cochlear model proposed by Roy Patterson is used as the auditory Filterbanks [7]. In this paper, an analysis/synthesis system based on the natural Cochlear model and the human auditory perception properties is presented that is capable of coding the speech signal under harsh acoustic conditions. The algorithm consists of the following stages: (1) cochlear filtering, by means of an ear model based on the gammatone filter-bank, (2) modulation filtering, by means of a constant-Q band-pass modulation filter-bank (3) peak detection and sensorimotor filtering; (4) feedforward control of a simple plant to simulate tapping. based on an auditory periphery model [13]. v1220. 2.1 Gammatone filterbank for cochlear modeling Gammatone filters are well know to fit basilar membrane response to an impulse stimuli [12]. 2.2. On the second hand, we propose an adaptation of this cochlear model for modeling a rat whiskers array. The purpose of this research is to compare Roy Patterson's gammatone filter-bank model of pitch perception with the Meddis-Lyon cochlear model that combines autocorrelation with automatic gain control. A gammatone filter bank is often used as the front end of a cochlea simulation, which transforms complex sounds into a multichannel activity pattern like that observed in the auditory nerve. 2379-2389. Zero Gammatone Filter (OZGF) is presented together with its automatic gain control that models its level-dependent nonlinear behaviour. 2 . Journal of the Acoustical Society of America. The free C implementation of gammatone filters provided by Ma3 is used in this paper. I. Apple Computer Technical Report #35. Cochlear implants (CIs) are devices capable of restoring hearing function in profoundly-deaf patients to an acceptable degree of performance.