Endre søk
RefereraExporteraLink to record
Permanent link

Direct link
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
On Enhancement and Quality Assessment of Audio and Video in Communication Systems
Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för tillämpad signalbehandling.
2014 (engelsk)Doktoravhandling, med artikler (Annet vitenskapelig)
Abstract [en]

The use of audio and video communication has increased exponentially over the last decade and has gone from speech over GSM to HD resolution video conference between continents on mobile devices. As the use becomes more widespread the interest in delivering high quality media increases even on devices with limited resources. This includes both development and enhancement of the communication chain but also the topic of objective measurements of the perceived quality. The focus of this thesis work has been to perform enhancement within speech encoding and video decoding, to measure influence factors of audio and video performance, and to build methods to predict the perceived video quality. The audio enhancement part of this thesis addresses the well known problem in the GSM system with an interfering signal generated by the switching nature of TDMA cellular telephony. Two different solutions are given to suppress such interference internally in the mobile handset. The first method involves the use of subtractive noise cancellation employing correlators, the second uses a structure of IIR notch filters. Both solutions use control algorithms based on the state of the communication between the mobile handset and the base station. The video enhancement part presents two post-filters. These two filters are designed to improve visual quality of highly compressed video streams from standard, block-based video codecs by combating both blocking and ringing artifacts. The second post-filter also performs sharpening. The third part addresses the problem of measuring audio and video delay as well as skewness between these, also known as synchronization. This method is a black box technique which enables it to be applied on any audiovisual application, proprietary as well as open standards, and can be run on any platform and over any network connectivity. The last part addresses no-reference (NR) bitstream video quality prediction using features extracted from the coded video stream. Several methods have been used and evaluated: Multiple Linear Regression (MLR), Artificial Neural Network (ANN), and Least Square Support Vector Machines (LS-SVM), showing high correlation with both MOS and objective video assessment methods as PSNR and PEVQ. The impact from temporal, spatial and quantization variations on perceptual video quality has also been addressed, together with the trade off between these, and for this purpose a set of locally conducted subjective experiments were performed.

sted, utgiver, år, opplag, sider
Karlskrona: Blekinge Institute of Technology , 2014.
Serie
Blekinge Institute of Technology Doctoral Dissertation Series, ISSN 1653-2090 ; 16
Emneord [en]
QoE, video quality assessment, video quality metric, multi-linear regression, artificial neural network, support vector machine, quality predictor, machine learning, temporal scaling, spatial scaling, video compression, deblocking filter, noise cancelling, synchronization, audio delay, video delay, GSM interference signal, noise cancellation, notch filtering
HSV kategori
Identifikatorer
URN: urn:nbn:se:bth-00604Lokal ID: oai:bth.se:forskinfoDE7E8BB7B60A3B4EC1257D820035F0B6ISBN: 978-91-7295-295-9 (tryckt)OAI: oai:DiVA.org:bth-00604DiVA, id: diva2:833999
Tilgjengelig fra: 2014-12-11 Laget: 2014-10-31 Sist oppdatert: 2017-03-14bibliografisk kontrollert

Open Access i DiVA

fulltekst(3373 kB)472 nedlastinger
Filinformasjon
Fil FULLTEXT01.pdfFilstørrelse 3373 kBChecksum SHA-512
e85008425fd65aa57f0362fa574545dfe250a3ac2aea95f16c0b523f35d0d63787c355ba43344729c1f448251b3f95e59757dcb5b530cb7c749c0dcc2899772c
Type fulltextMimetype application/pdf

Personposter BETA

Rossholm, Andreas

Søk i DiVA

Av forfatter/redaktør
Rossholm, Andreas
Av organisasjonen

Søk utenfor DiVA

GoogleGoogle Scholar
Totalt: 472 nedlastinger
Antall nedlastinger er summen av alle nedlastinger av alle fulltekster. Det kan for eksempel være tidligere versjoner som er ikke lenger tilgjengelige

isbn
urn-nbn

Altmetric

isbn
urn-nbn
Totalt: 248 treff
RefereraExporteraLink to record
Permanent link

Direct link
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf