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Proceedings Paper

Subjective quality assessment and the effect of context in expert and nonexpert viewers
Author(s): Filippo Speranza; Taali Martin; Ron Renaud
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Paper Abstract

The perceived quality of video sequences is generally measured using standard subjective methods. It has been argued that these methods, which typically consist of scaling judgment tasks, are affected by context effects. Context effects are observed when the perceived quality of a video sequence is influenced by the perceived quality of the other video sequences included in the test. Several studies have confirmed the presence of context effects. However, the same studies are ambiguous with respect to the issue of which methods are affected the most. In addition, context effects have been investigated mainly with non-expert viewers. In this study, we investigated context effects in both expert and non-expert viewers. Two experiments were conducted to investigate the relationships between context effects, level of expertise, and type of subjective method. In Experiment 1, we measured range and frequency context effects for two different subjective assessment methods, a double stimulus method (i.e., DSCQS) and a comparison scaling method, using non-expert viewers. We found no frequency context effect with both methods, and a marginal range context effect with the DSCQS method. In Experiment 2, we obtained the same measurements with expert viewers. We found no context frequency effect for both subjective methods, and a very small range context effect for the comparison method only.

Paper Details

Date Published: 18 December 2003
PDF: 10 pages
Proc. SPIE 5294, Image Quality and System Performance, (18 December 2003); doi: 10.1117/12.526101
Show Author Affiliations
Filippo Speranza, Communications Research Ctr. Canada (Canada)
Taali Martin, Communications Research Ctr. Canada (Canada)
Ron Renaud, Communications Research Ctr. Canada (Canada)

Published in SPIE Proceedings Vol. 5294:
Image Quality and System Performance
Yoichi Miyake; D. Rene Rasmussen, Editor(s)

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