Abhijit Karmakar

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A criterion is proposed to obtain an optimal wavelet packet (WP) tree based on the critical band structure of the human auditory system for time-frequency decomposition of speech and audio signals. The criterion minimizes a perceptual cost function based on Zwicker's model of the critical band structure and allocates an optimal number of terminating nodes(More)
The spectral subtraction is a traditional approach for enhancing the quality of speech degraded by environmental noise. This algorithm is based on the subtraction of the estimated noise spectrum from the noisy speech spectrum and combines it with the phase of the noisy speech. Besides suppressing the noise, this method introduces an unnatural and unpleasant(More)
CORDIC is an iterative arithmetic computing algorithm capable of evaluating various elementary functions using a unified shift-and-add operations. Fast Fourier Transform processor based on CORDIC is implemented. The key ideas are replacing the sine and cosine twiddle factors in conventional FFT architecture by iterative CORDIC rotations which allow the(More)
This paper proposes a multiresolution model of auditory excitation pattern and applies it to the problem of objective evaluation of subjective wideband speech quality. The model uses wavelet packet transform for time-frequency decomposition of the input signal. The selection of the wavelet packet tree is based on an optimality criterion formulated to(More)
A simple method for the design of an optimal two-channel finite impulse response (FIR) orthogonal filterbank that minimizes the stopband energy of the filter's impulse response using semidefinite programming (SDP) is presented. The convex formulation is obtained by representing the optimality criterion and the orthogonality constraints in terms of the(More)
The spectral subtraction method is a conventional approach for single channel speech enhancement. The basic principle of this method is to estimate the short-time spectral magnitude of speech by subtracting estimated noise from the noisy speech spectrum and to combines it with the phase of the noisy speech. Besides reducing the noise, this method generates(More)
Emerging embedded system applications require low power, fast and area-efficient implementation of complex arithmetic operations. Modern field-programmable gate array (FPGA) is a suitable candidate for implementing any reasonably complex architecture within minimal design time. Apart from the logic resources, most of the FPGAs contain hard-macro elements.(More)
A method is proposed for synthesizing an optimal wavelet based on auditory perception criterion for dyadic filter bank implementation. The design method of this perceptually optimized wavelet is based on the critical band (CB) structure and the temporal resolution of human auditory system (HAS). The construction of this compactly supported wavelet is done(More)
Real-time numerically intensive image processing applications demand dedicated hardware for various complex arithmetic functions. These arithmetic functions can be efficiently implemented by employing a binary logarithmic circuit. In this paper a field-programmable gate array (FPGA) based architecture for the binary logarithm approximation unit is proposed.(More)
To achieve the goal of secure communication, cryptography is an essential operation. Many applications, including health-monitoring and biometric data based recognition system, need short-term data security. To design short-term security based applications, there is an essential need of high-performance, low cost and area-efficient VLSI implementation of(More)