( )Engineering Information Abstracts Part I454

Ž .In English Author abstract 2 Refs. EI Order Number:98054183901Keywords: Speech processing; Speech transmission; Fre-quency shift keying; Adaptive filtering; Signal to noise ratio;Signal detection

Title: NEW APPROACH TO PITCH AND VOICING DETEC-TION THROUGH SPECTRUM PERIODICITY MEASURE-MENT

( )Author s : Ghaemmaghami, S.; Deriche, M.; Boashash, B.Source: Proceedings of the 1997 IEEE TENCON Conference.

Ž .Part 2 of 2 Dec 2-4 1997 v 2 Brisbane, Australia. Sponsoredby: IEEE Piscataway NJ USA. p 743-746 CODEN: 85QXAAPublication Year: 1997Abstract: A new method for detecting pitch and voicing infor-mation of speech with a high accuracy is addressed. Themethod is based on a novel approach to using the concept of

Ž .Instantaneous Frequency IF . In this method, an IF estima-tion technique in frequency domain is employed to exposeharmonic structure of the signal using a periodicity measure.This measure is based on the flatness of the IF, which de-scribes the spectrum periodicity within a certain frequencyband where the pitch harmonics are most likely found. Theflatness measurement also yields voicing information extractedusing an auto-thresholding technique. The proposed methodwas evaluated through comparison with cepstral pitch andvoicing detection considering accuracy and reconstructed

Ž .speech quality. In English Author abstract 8 Refs. EI OrderNumber: 98054183898Keywords: Speech analysis; Speech recognition; Speech pro-cessing; Signal processing; Speech coding

Title: ROBUST MOTION ESTIMATION USING COMPLEXWAVELETS

( )Author s : Magarey, Julian; Kingsbury, NickSource: Proceedings of the 1997 IEEE TENCON Conference.

Ž .Part 2 of 2 Dec 2-4 1997 v 2 Brisbane, Australia. Sponsoredby: IEEE Piscataway NJ USA. p 655-658 CODEN: 85QXAAPublication Year: 1997Abstract: This paper describes a new approach to the problemof estimating motion in video image sequences. The algorithmoperates on the complex coefficients obtained by applying thenew Complex Discrete Wavelet Transform to each frame. Thistransform implements an efficient analysis by an ensemble ofGabor-like filters of different orientation and scales. TheGabor-like form of the filters means that local translationsinduce phase rotations in the corresponding complex coeffi-cients. This relationship is used to estimate motion at eachsubpixel of each scale. The estimates are combined over allorientations and scales using a coarse-to-fine refinement strat-egy to produce a fractional-pel accurate motion field with adirectional confidence measure. Compared with intensity-based algorithms, the new algorithm is robust to simple image

Ž .formation perturbations. In English Author abstract 6 Refs.EI Order Number: 98054183877Keywords: Algorithms; Wavelet transforms; Perturbationtechniques; Video signal processing; Mathematical models;Vectors

Title: ROBUST SPEECH RECOGNITION USING SINGU-LAR VALUE DECOMPOSITION BASED SPEECH EN-HANCEMENT

( )Author s : Lilly, B.T.; Paliwal, K.K.Source: Proceedings of the 1997 IEEE TENCON Conference.

Ž .Part 1 of 2 Dec 2-4 1997 v 1 Brisbane, Australia. Sponsoredby: IEEE Piscataway NJ USA. p 257-260 CODEN: 85QXAAPublication Year: 1997Abstract: Speech recognition systems work reasonably well inlaboratory conditions, but their performance deterioratesdrastically when they are deployed in practical situations wherethe speech is corrupted by additive noise. One way to improvethe performance of a speech recognition system in the pres-ence of noise, is to enhance the speech prior to its recogni-tion. Two singular value decomposition based techniques havebeen recently proposed for speech enhancement. In thesetechniques, singular value decomposition has been applied toan over-determined, over-extended data matrix formed fromthe noisy speech signal. A noise-free, low rank approximationwas obtained by retaining a specific number of singular values.This technique was applied here as a preprocessor for recog-nizing speech in the presence of noise. It was found toimprove the recognition performance significantly for signal-

Ž .to-noise ratios less than 15 dB. In English Author abstract 9Refs. EI Order Number: 98054179720Keywords: Speech recognition; Speech processing; Signal tonoise ratio

Title: TIME-FREQUENCY PLANE WIENER FILTERINGFOR ROBUST PROCESSING OF SPEECH SIGNALS

( )Author s : Ang, Adrian; Ang, Ee-Luang; Premkumar, A.B.;Madhukumar, A.S.Source: Proceedings of the 1997 IEEE TENCON Conference.

Ž .Part 1 of 2 Dec 2-4 1997 v 1 Brisbane, Australia. Sponsoredby: IEEE Piscataway NJ USA. p 35-38 CODEN: 85QXAAPublication Year: 1997Abstract: This paper uses discrete wavelet transforms togetherwith Wiener filtering to enhance noisy speech for furtherprocessing. The speech signal is mixed with various levels ofwhite and coloured noises and decomposed into several levelsusing wavelet analysis. The output signal at each level isprocessed separately using iterative Wiener filtering. An effi-cient speech coding system is developedfor the enhanced

Ž .speech bands. In English Author abstract 5 Refs. EI OrderNumber: 98054179666Keywords: Speech coding; Signal filtering and prediction; Timedomain analysis; Frequency domain analysis; Wavelet trans-forms; White noise; Iterative methods; Speech analysis

Title: FULLY DIGITAL AUTO-FOCUSING SYSTEM BASEDON IMAGE RESTORATION

( )Author s : Kim, Sang Ku; Kim, Tae Keun; Paik, Joon KiSource: Proceedings of the 1997 IEEE TENCON Conference.

Ž .Part 1 of 2 Dec 2-4 1997 v 1 Brisbane, Australia. Sponsoredby: IEEE Piscataway NJ USA. p 13-15 CODEN: 85QXAA