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Open Access

A Perceptually Relevant No-Reference Blockiness Metric Based on Local Image Characteristics

EURASIP Journal on Advances in Signal Processing20092009:263540

Received: 4 July 2008

Accepted: 21 January 2009

Published: 2 March 2009


A novel no-reference blockiness metric that provides a quantitative measure of blocking annoyance in block-based DCT coding is presented. The metric incorporates properties of the human visual system (HVS) to improve its reliability, while the additional cost introduced by the HVS is minimized to ensure its use for real-time processing. This is mainly achieved by calculating the local pixel-based distortion of the artifact itself, combined with its local visibility by means of a simplified model of visual masking. The overall computation efficiency and metric accuracy is further improved by including a grid detector to identify the exact location of blocking artifacts in a given image. The metric calculated only at the detected blocking artifacts is averaged over all blocking artifacts in the image to yield an overall blockiness score. The performance of this metric is compared to existing alternatives in literature and shows to be highly consistent with subjective data at a reduced computational load. As such, the proposed blockiness metric is promising in terms of both computational efficiency and practical reliability for real-life applications.


Quantum InformationComputational EfficiencySubjective DataHuman Visual SystemComputation Efficiency

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Authors’ Affiliations

Department of Mediamatics, Delft University of Technology, Delft, The Netherlands
Group Visual Experiences, Philips Research Laboratories, Eindhoven, The Netherlands


© H. Liu and I. Heynderickx. 2009

This article is published under license to BioMed Central Ltd. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.