Accession Number : ADA308262

Title :   Speech Compression Using Cosine Packet Decomposition.

Descriptive Note : Master's thesis,

Corporate Author : NAVAL POSTGRADUATE SCHOOL MONTEREY CA

Personal Author(s) : Vasconcellos, Joao R.

PDF Url : ADA308262

Report Date : MAR 1996

Pagination or Media Count : 157

Abstract : As digitization of data becomes more prevalent, the demands on existing communications networks and computer systems to cope with this increase in data become overwhelming. Currently, the speech compression problem is handled using the CELP( Code Excited Linear Prediction) scheme and its derivatives. Such techniques are the most frequently used for speech compression at medium-to-low rate ranges. Recent research conducted into the area of cosine packets has proven this field to be readily adaptable to speech compression and coding. In this thesis, speech compression schemes are developed using cosine-packet decomposition, minimum entropy basis selection, and an adaptive thresholding scheme for selecting coefficients. In addition, voiced-unvoiced segmentation and a denoising scheme were implemented. Test results showed high compression ratios (1:50) with a good quality of reconstructed speech.

Descriptors :   *DATA COMPRESSION, *ACOUSTIC DATA, *VOICE COMMUNICATIONS, *SPEECH COMPRESSION, DATA BASES, ALGORITHMS, SIGNAL PROCESSING, FOURIER TRANSFORMATION, OPTIMIZATION, THRESHOLD EFFECTS, RESOLUTION, SIGNAL TO NOISE RATIO, THESES, INPUT OUTPUT PROCESSING, COMMUNICATIONS NETWORKS, ACOUSTIC SIGNALS, SPEECH RECOGNITION, SPEECH TRANSMISSION, NOISE REDUCTION, ACOUSTIC FILTERS, BANDWIDTH, DIGITAL COMMUNICATIONS, BACKGROUND NOISE, HIGH PASS FILTERS, LOW PASS FILTERS, SOUND PITCH, AUDIO FREQUENCY, DECODING, PACKET SWITCHING, COMPRESSION RATIO, PHONEMES.

Subject Categories : Acoustics
      Voice Communications
      Computer Programming and Software

Distribution Statement : APPROVED FOR PUBLIC RELEASE