Vanishree Gopalakrishna

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This paper presents a wavelet-based speech coding strategy for cochlear implants. In addition, it describes the real-time implementation of this strategy on a personal digital assistant (PDA) platform. Three wavelet packet decomposition tree structures are considered and their performance in terms of computational complexity, spectral leakage, fixed-point(More)
This paper presents the real-time implementation of wavelet-based Advanced Combination Encoder on PDA platforms for cochlear implant studies. Three real-time implementations using the conventional FFT, our previous recursive DFT, and the wavelet transform are compared in terms of computational complexity, processing time and fixed-point accuracy. The(More)
This paper presents a real-time and interactive implementation of the recursive Fourier transform approach on PDA platforms for cochlear implant signal processing applications. PDA platforms provide a cost-effective and portable platform for cochlear implant studies. The computational complexities of the two commonly used signal processing strategies that(More)
The present paper describes the design of two stimulators (bench-top and portable) which can be used for animal studies in cochlear implants. The bench-top stimulator is controlled by a high-speed digital output board manufactured by National Instruments and is electrically isolated. The portable stimulator is controlled by a personal digital assistant(More)
Cochlear implant patients often complain about their difficulty in understanding speech in noisy environments. Currently a fixed noise suppression algorithm is used in cochlear implants regardless of the characteristics of the speech or noise environment. Access to an intelligent mechanism to determine the noise environment on-the-fly in order to(More)
A computationally efficient speech enhancement pipeline in noisy environments based on a single-processor implementation is developed for utilization in bilateral cochlear implant systems. A two-channel joint objective function is defined and a closed form solution is obtained based on the weighted-Euclidean distortion measure. The computational efficiency(More)
This paper presents the real-time implementation of an environment-adaptive noise suppression algorithm on an FDA-approved PDA platform for cochlear implant studies. This added capability involves identifying the background noise environment in real-time and adapting a data-driven noise suppression approach to that noise environment on-the-fly. Various(More)
The performance of cochlear implants deteriorates in noisy environments compared to quiet conditions. This paper presents an adaptive cochlear implant system, which is capable of classifying the background noise environment in real time for the purpose of adjusting or tuning its noise suppression algorithm to that environment. The tuning is done(More)