Papers by prabhakar agarwal
International Journal of System Assurance Engineering and Management
IJPAP Vol.59(03) [March 2021], Mar 1, 2021
With the advancement of engineering solutions in the medical domain, the patient's life can becom... more With the advancement of engineering solutions in the medical domain, the patient's life can become comfortable. This work recognizes the silent speech of three words. The decoding of silent speech can be useful for patients who are in a locked-in syndrome state. Moreover, it is also applicable to entertainment, cognitive biometrics, and brain-computer interfacing. Brain waves of these imagined words in the delta, theta, alpha, beta, gamma, and high gamma frequency bands are analysed. Covariance based connectivity features are extracted in each frequency band. The principal features which represent more than 95% of the variance are selected as a subset of the covariance connectivity matrix. This subset is tested on five classifiers. The maximum accuracy achieved is 76.4% in the theta band. Also, theta and high gamma band contain maximum information about imagined speech with average accuracies of 68.32% and 62.09% respectively.
Int. J. Speech Technol., 2021
For enhancing the performance of the quality of speech, this paper presents a novel, hybrid speec... more For enhancing the performance of the quality of speech, this paper presents a novel, hybrid speech enhancement technique based on the combination of two-step noise reduction (TSNR), harmonic regeneration noise reduction (HRNR), and a comb filter. This technique outperforms existing methods that are based on TSNR, HRNR, Wavelet, and hybrid TSNR-HRNR. The parameters such as spectrogram, average segmental SNR (ASSNR), mean square error (MSE), mean opinion score (MOS), perceptual evaluation of speech quality (PESQ), and diagnostic rhyme test (DRT) were obtained for the performance comparison. Results revealed that the proposed method outperforms in terms of ASSNR, MSE, speech quality, and intelligibility when compared to the TSNR, HRNR, wavelet, and TSNR-HRNR based speech enhancement methods.
FRFT is the abbreviation of fractional Fourier transform and it is generalization of the classica... more FRFT is the abbreviation of fractional Fourier transform and it is generalization of the classical Fourier transform. Fourier transform can only be used for stationary signals but FRFT can process non-stationary signals in real time. In this work, the closed form solutions of Dirichlet, Hamming and Hanning window functions are solved in FRFT domain. Then, simulations of the window functions are carried out in Maple 13 software. FRFT has an adjustable parameter $\beta$, which can be used to vary the main and side lobes width of the window function and the trade-off between them can be seen from the graphs. The range of $\beta$ lies between 0 and 1.
International Journal of Imaging Systems and Technology
2020 7th International Conference on Signal Processing and Integrated Networks (SPIN)
Envisioned speech captured by EEG signals is a fascinating area of research as this is useful in ... more Envisioned speech captured by EEG signals is a fascinating area of research as this is useful in bio-medical applications for the patients suffering from motor neuron diseases and also in those areas where silent speech is desirable. This work examines the possibility of better feature extraction techniques from which a robust model with the help of a classifier can be built. Results showed that Common Spatial Patterns (CSP) filter coefficients in a combination of statistical features with Random Forest as a classifier turn out to be a suitable choice. Three imagined tasks /a/, /u/ and /rest/ were discriminated with highest accuracy reaching up to 89%.
International Journal of System Assurance Engineering and Management
An electroencephalogram (EEG) based brain-computer interface (BCI) enables the control of some ex... more An electroencephalogram (EEG) based brain-computer interface (BCI) enables the control of some external activity directly from the brain, without any physical movement/overt action. The external activity can be the cursor control of a computer or it can provide commands to the devices to perform certain functions. This work proposes a movement imagery (MI) based graphical user interface (GUI) for typing 26 English alphabets and tasks like food, water, medicine along with cancel and confirm commands. Convolutional Neural Network (CNN) is used to extract the spatial features from the recorded EEG signals. These features are fed to an ensemble-based extreme gradient (XG) boost classifier in a five-classification framework. By varying the hyper-parameters of the classification model, the highest accuracy of 84.7% for CNN and 92.87% for the cascaded structure of CNN and the XG boost classifier is achieved. The minimum execution time taken is 1.18 s for CNN and 3.24 s using both CNN and XG boost classifier. The work shows that it is possible to classify the information embedded in MI signals and can serve as a basis for an alternate communication channel to patients in advanced stages of Amyotrophic lateral sclerosis.
International Journal of Speech Technology
In this paper, the performance comparison of three pitch detection algorithms (PDAs) has been pre... more In this paper, the performance comparison of three pitch detection algorithms (PDAs) has been presented by implementing them in a LPC based speech analysis-synthesis system. The PDAs considered for comparison is based on three paradigms. The paradigms are weighted autocorrelation function (WACF), Empirical Mode Decomposition based autocorrelation function (EMD-ACF) and Empirical Mode Decomposition based average magnitude difference function (EMD-AMDF). Speech quality measurement is an important and essential task to ensure and maintain the quality of services for speech processing applications like modern telecommunication. Hence, the performance of these methods has been compared through the output speech quality using objective (perceptual evaluation of speech quality test) and subjective quality assessment (Mean Opinion Score test, diagnostic rhyme test and synthesized speech waveforms). The results show that the speech quality for the EMD-ACF and EMD-AMDF based PDA’s are better than that for WACF based PDA. The works presented in this paper is beneficial to telecommunication and speech recognition research group.
2013 3rd IEEE International Advance Computing Conference (IACC), 2013
With the increasing need of spectrum, various computational methods and algorithms have been prop... more With the increasing need of spectrum, various computational methods and algorithms have been proposed in the literature. Keeping these views and facts of spectrum shaping capability by FRFT based windows we have proposed a closed form solution for Dirichlet window in fractional domain. This may be useful for analysis of different upcoming generations of mobile communication in better ways which are based on OFDM technique. Moreover, it is useful for real-time processing of nonstationary signals.
2014 International Conference on Medical Imaging, m-Health and Emerging Communication Systems (MedCom), 2014
We have presented closed form solution for Blackman window function in fractional Fourier transfo... more We have presented closed form solution for Blackman window function in fractional Fourier transform domain (FRFT). The closed form solution may be used for performance improvement in Orthogonal Frequency Division Multiplexing based communication system. Moreover, they may be useful for real-time processing of non-stationary signals. One can see from simulation results that as the value of the tunable parameter α of the FRFT is increased from 0 to 1, reduction in side-lobe levels takes place which in turn broadens the main-lobe width, thus trade-off is evident and one can chose the best window function according to the desired application.
2014 International Conference on Medical Imaging, m-Health and Emerging Communication Systems (MedCom), 2014
This paper deals with the application of the raw ECG signal and best window technique used to des... more This paper deals with the application of the raw ECG signal and best window technique used to design FIR filter by comparing the spectral densities and average power before filtration and after filtration. In this work we have used different ECG databases from Physionet for assessing the quality of the algorithms developed.
International Journal of System Assurance Engineering and Management
With the advent of new algorithms, brain-computer interfacing has been extensively used in medica... more With the advent of new algorithms, brain-computer interfacing has been extensively used in medical and non-medical fields. In this regard, an experiment was conducted by the authors to recognize the imagined speech, the results of which are reported in this paper. This work can act as a speech prosthesis for completely paralyzed patients who cannot communicate normally. Thirteen subjects imagined five English words (sos, stop, medicine, comehere, washroom) while their electroencephalogram (EEG) signals were recorded simultaneously. The word pairs were analyzed in six natural frequencies of the brain. The envelopes of analytical signals acquired from Hilbert transform were calculated for all the frequency bands and the resulting features were classified using seven classifiers. The maximum accuracy reached up to 88.36%. The experimental study showed that alpha and theta frequency bands were able to classify the highest amount of imagined speech with a maximum average accuracy of 72.73% and 69.41% respectively. The results were comparable to state-of-the-art methods. The findings reported in this work will encourage the research community to use non-invasive modalities like EEG for exploring more in this area.
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Papers by prabhakar agarwal