Radu Mihnea Udrea

Universitatea Națională de Știință și Tehnologie Politehnica București | UPB · Department of Telecommunications

This paper presents a robust system to improve speech signals processed by communication systems. The system includes multi-microphone techniques, for which both spectral and spatial characteristics of the signal sources can be used. Also a spectral subtraction algorithm for noise reduction is integrated into the system. The modified spectral subtr...

The normalized least-mean-square algorithm (NLMS) is frequently used in the context of acoustic echo cancellation (AEC). However, in order to meet the conflicting requirements of fast convergence and tracking versus low misadjustment, the variable step-size NLMS (VSS-NLMS) algorithms were found to be more suitable in practice. In this paper, we ana...

This paper proposes an algorithm for accurate detection of salient areas from a given scene. We used a complex model for the human visual system, in order to simulate the visual perception mechanisms. Human visual system modelling requires accurate knowledge about the entire visual pathways. This work focuses on the following features of the human...

We propose an improved spectral subtraction method for the reduction of colored acoustic noise added to the speech. Our implementation uses a time-recursive algorithm for estimation of the noise power spectral density and a multi-band spectral over subtraction method to reduce the colored noise. Simulations show a better quality in terms of Itakura...

This paper proposes an algorithm for accurate detection of salient areas from a given scene. We used a complex model for the human visual system, in order to simulate the visual perception mechanisms. Human visual system modelling requires accurate knowledge about the entire visual pathways. This work focuses on the following features of the human...

A new and improved visual-oriented grayscale frames interpolation method consists of partially changing, step by step using growing structuring elements, the morphological S transforms of the foreground content of an input frame with the morphological S transforms of the foreground content of an output frame. Better performance comes at the expense...

Video based applications and services usually require at some stage a reliable video quality evaluation method that can give an estimate for the human perceived video quality. While most research is performed in the area of human visual system modeling, we propose a quality metric which first estimates the perceptually important areas using the key...

We propose an improved spectral subtraction method for reducing acoustic noise added to speech in noisy environments like helicopter cockpit or car engine. This implementation uses oversubtraction method for spectral subtraction. Residual noise can be masked by exploiting the masking properties of the human auditory system. A psychoacoustically mot...

In this paper we present the multimedia content extraction method based on region and object segmentation. The process of content extraction represents one step in solving the problem of content adaptation. Adaptation means the preparation and delivery of content that matches the resources of the connected terminal or network in an optimal way. The...

We propose an improved spectral subtraction method for the reduction of colored acoustic noise added to the speech in a helicopter cockpit or in a car caused by the engine sound. Our implementation uses an over-estimation subtraction method for spectral subtraction. The noise signal does not affect uniformly the speech signal over the whole spectru...

A precise and efficient quantized multiple sinusoids signal estimation algorithm is presented. For different initial conditions obtained using classical spectral estimation algorithms the final solution of our algorithm is not unique. We start to minimize a nonlinear cost function. The accuracy of the initial values of iterations has a large influe...

In this paper we present new content analysis methods effective in multimedia based services. The problem of multimedia content delivery and retrieval has become more and more important due to the growing amount of video information that is delivered to consumers today. The classical searching and retrieval mode in multimedia databases is by name;...

We propose an improved spectral subtraction method for reducing acoustic noise added to speech in noisy environments like helicopter cockpit or car engine. This implementation uses over-subtraction method for spectral subtraction. Residual noise can be masked by exploiting the masking properties of the human auditory system. A psychoacoustically mo...

This paper addresses the representation of binary images using mathematical morphology, a nonlinear theory for image processing, based on set theory. The new image representation, called "five-step" skeleton representation, is an extension of the morphological binary skeleton. It consists of calculating the morphological digital binary skeleton usi...

The paper presents a new method for generating a class of S-type nonlinear current controlled negative resistances. The presented method can be used to obtain a large number of nonlinear resistances. We apply the method for a negative resistance device, using bipolar transistors, described by theoretical characteristics and we compare the results w...

The paper presents a new method for generating S-type nonlinear current controlled negative resistances. The presented method can be used to obtain a large number of nonlinear resistances. We apply the method for a negative resistance device, using bipolar transistors, described by theoretical characteristics and performances and we compare the res...

A precise and efficient new and improved multiple quantized sinusoid estimation algorithm is presented. This algorithm is more precise and efficient than existing algorithms. The metrological requests are studied.

In this paper we propose an improved method for reducing background noise added to speech in noisy environments like helicopter cockpit or car engine. This implementation uses over-subtraction method for spectral subtraction. Masking properties of the human ear are exploited to reduce the residual noise after spectral subtraction. A psychoacoustica...

We propose an improved spectral subtraction method for reducing acoustic noise added to speech in colored noise environments like helicopter cockpit or car engine. This implementation uses over-subtraction method for spectral subtraction. The noise signal does not affect the speech signal uniformly over the whole spectrum. A nonlinear multi-band Ba...

PSPICE has become one of the most well known circuit analysis programs. This work presents new methods of simulating the algebraic functions as well as the solving of non-linear differential equations. A new negative resistance oscillator model was used for the single and double mode LCR networks of ECAM. Analytic approximations are compared with t...

Abstract

In this paper, we propose an improved spectral subtraction method for enhancing noise-corrupted speech. This implementation uses over-subtraction method for power spectral subtraction and a modified residual noise reduction algorithm to eliminate musical noise. Performance of the algorithm was compared with previous spectral subtraction methods usi...

This paper presents an innovative solution of a mixed signal system on a chip that integrates all the electronic blocks of a hard disk drive in a single chip. This solution has been entirely designed, implemented and tested by LSI Design and Integration Corporation (LDIC), being the first integrated circuit of this complexity designated for the har...

A new and improved single quantized sinusoid estimation and generation algorithm is presented. This algorithm is more precise and efficient than existing algorithms. The metrological requests are studied. Finally the sinusoid is generated using DSP processors.

There are many situations where speech is affected by different kind of acoustic noise. We propose an improved spectral subtraction method for the reduction of colored acoustic noise added to the speech. Our implementation uses a multi-band spectral over subtraction method to reduce the colored noise. We use a non-linear Bark scale distribution to...