miun.sePublications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Temporal filter with bilinear interpolation for ROI video coding
Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media. (Realistic3D, SensibleReality, MUCOM)
Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media. (Realistic3D, SensibleReality, MUCOM)
Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media. (Realistic3D, SensibleReality, MUCOM)ORCID iD: 0000-0003-3751-6089
Responsible organisation
2006 (English)Report (Other academic)
Abstract [en]

In videoconferencing and video over the mobile phone, themain visual information is found within limited regions ofthe video. This enables improved perceived quality byregion-of-interest coding. In this paper we introduce atemporal preprocessing filter that reuses values of theprevious frame, by which changes in the background areonly allowed for every second frame. This reduces the bitrateby 10-25% or gives an increase in average PSNR of0.29-0.98 dB. Further processing of the video sequence isnecessary for an improved re-allocation of the resources.Motion of the ROI causes absence of necessary backgrounddata at the ROI border. We conceal this by using a bilinearinterpolation between the current and previous frame at thetransition from background to ROI. This results in animprovement in average PSNR of 0.44 – 1.05 dB in thetransition area with a minor decrease in average PSNRwithin the ROI.

Place, publisher, year, edition, pages
Sundsvall: Mid Sweden Univ. Dept. of Information Technology and Media , 2006.
Series
MUCOM technical report
National Category
Computer Sciences
Identifiers
URN: urn:nbn:se:miun:diva-5879Local ID: 4073OAI: oai:DiVA.org:miun-5879DiVA, id: diva2:30912
Projects
STC - Sensible Things that CommunicateAvailable from: 2009-07-29 Created: 2009-02-02 Last updated: 2018-01-12Bibliographically approved
In thesis
1. Spatio-Temporal Pre-Processing Methods for Region-of-Interest Video Coding
Open this publication in new window or tab >>Spatio-Temporal Pre-Processing Methods for Region-of-Interest Video Coding
2007 (English)Licentiate thesis, monograph (Other academic)
Abstract [en]

In video transmission at low bit rates the challenge is to compress the video with a minimal reduction of the percieved quality. The compression can be adapted to knowledge of which regions in the video sequence are of most interest to the viewer. Region of interest (ROI) video coding uses this information to control the allocation of bits to the background and the ROI. The aim is to increase the quality in the ROI at the expense of the quality in the background. In order for this to occur the typical content of an ROI for a particular application is firstly determined and the actual detection is performed based on this information. The allocation of bits can then be controlled based on the result of the detection.

In this licenciate thesis existing methods to control bit allocation in ROI video coding are investigated. In particular pre-processing methods that are applied independently of the codec or standard. This makes it possible to apply the method directly to the video sequence without modifications to the codec. Three filters are proposed in this thesis based on previous approaches. The spatial filter that only modifies the background within a single frame and the temporal filter that uses information from the previous frame. These two filters are also combined into a spatio-temporal filter. The abilities of these filters to reduce the number of bits necessary to encode the background and to successfully re-allocate these to the ROI are investigated. In addition the computational compexities of the algorithms are analysed.

The theoretical analysis is verified by quantitative tests. These include measuring the quality using both the PSNR of the ROI and the border of the background, as well as subjective tests with human test subjects and an analysis of motion vector statistics.

The qualitative analysis shows that the spatio-temporal filter has a better coding efficiency than the other filters and it successfully re-allocates the bits from the foreground to the background. The spatio-temporal filter gives an improvement in average PSNR in the ROI of more than 1.32 dB or a reduction in bitrate of 31 % compared to the encoding of the original sequence. This result is similar to or slightly better than the spatial filter. However, the spatio-temporal filter has a better performance, since its computational complexity is lower than that of the spatial filter.

Place, publisher, year, edition, pages
Sundsvall: Mid Sweden Univ, 2007. p. 112
Series
Mid Sweden University licentiate thesis, ISSN 1652-8948 ; 21
Keywords
Region-of-interest, video coding, pre-processing, spatio-temporal filters
National Category
Information Systems
Identifiers
urn:nbn:se:miun:diva-51 (URN)5113 (Local ID)978-91-85317-45-5 (ISBN)5113 (Archive number)5113 (OAI)
Presentation
2007-04-27, L111, L, Mittuniversitetet, Sundsvall, 13:00 (English)
Opponent
Supervisors
Available from: 2007-12-20 Created: 2007-12-20 Last updated: 2018-01-13Bibliographically approved

Open Access in DiVA

fulltext(191 kB)360 downloads
File information
File name FULLTEXT01.pdfFile size 191 kBChecksum SHA-512
b3951a99a5d0bcad37a18ae1a7c271086595be7e228671e3843cde04c102bd39d7b63efbea9187dc243c9af04f5e6464c44f3926616eb73aded4b0a2ab3f677b
Type fulltextMimetype application/pdf

Authority records BETA

Karlsson, LindaOlsson, RogerSjöström, Mårten

Search in DiVA

By author/editor
Karlsson, LindaOlsson, RogerSjöström, Mårten
By organisation
Department of Information Technology and Media
Computer Sciences

Search outside of DiVA

GoogleGoogle Scholar
Total: 360 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

urn-nbn

Altmetric score

urn-nbn
Total: 957 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf