Image database TID2013: Peculiarities, results and perspectives

TLDR

The paper introduces TID2013, an image database designed to evaluate full‑reference visual quality assessment metrics. TID2013 contains 3,000 distorted images derived from 25 reference images, covering 24 distortion types at five levels plus seven new types and an extra level, with mean opinion scores collected from 985 observers across five countries, and the database and scores are freely downloadable for metric testing and correlation analysis. The collected MOS enable the database to serve as a benchmark, and rank‑order correlation analysis reveals the strengths and weaknesses of existing metrics, while the authors propose methods to identify distortion types where metrics fail to match human perception.

Abstract

This paper describes a recently created image database, TID2013, intended for evaluation of full-reference visual quality assessment metrics. With respect to TID2008, the new database contains a larger number (3000) of test images obtained from 25 reference images, 24 types of distortions for each reference image, and 5 levels for each type of distortion. Motivations for introducing 7 new types of distortions and one additional level of distortions are given; examples of distorted images are presented. Mean opinion scores (MOS) for the new database have been collected by performing 985 subjective experiments with volunteers (observers) from five countries (Finland, France, Italy, Ukraine, and USA). The availability of MOS allows the use of the designed database as a fundamental tool for assessing the effectiveness of visual quality. Furthermore, existing visual quality metrics have been tested with the proposed database and the collected results have been analyzed using rank order correlation coefficients between MOS and considered metrics. These correlation indices have been obtained both considering the full set of distorted images and specific image subsets, for highlighting advantages and drawbacks of existing, state of the art, quality metrics. Approaches to thorough performance analysis for a given metric are presented to detect practical situations or distortion types for which this metric is not adequate enough to human perception. The created image database and the collected MOS values are freely available for downloading and utilization for scientific purposes.