Subjective and Objective Quality Evaluation of Super-Resolution Enhanced Broadcast Images on a Novel SR-IQA Dataset

TL;DR

This paper introduces a new dataset for assessing the quality of super-resolution broadcast images, conducts human evaluations to understand perceived quality factors, and evaluates existing IQA metrics, revealing their limitations.

Contribution

The work presents a novel SR-IQA dataset for 2K and 4K broadcast images, along with a comprehensive human study and an evaluation of current IQA metrics on this dataset.

Findings

Current IQA metrics have limitations in assessing SR broadcast images.

Human perception is influenced by specific factors identified in the study.

Existing metrics do not fully align with subjective quality assessments.

Abstract

To display low-quality broadcast content on high-resolution screens in full-screen format, the application of Super-Resolution (SR), a key consumer technology, is essential. Recently, SR methods have been developed that not only increase resolution while preserving the original image information but also enhance the perceived quality. However, evaluating the quality of SR images generated from low-quality sources, such as SR-enhanced broadcast content, is challenging due to the need to consider both distortions and improvements. Additionally, assessing SR image quality without original high-quality sources presents another significant challenge. Unfortunately, there has been a dearth of research specifically addressing the Image Quality Assessment (IQA) of SR images under these conditions. In this work, we introduce a new IQA dataset for SR broadcast images in both 2K and 4K resolutions. We conducted a subjective quality evaluation to obtain the Mean Opinion Score (MOS) for these SR images and performed a comprehensive human study to identify the key factors influencing the perceived quality. Finally, we evaluated the performance of existing IQA metrics on our dataset. This study reveals the limitations of current metrics, highlighting the need for a more robust IQA metric that better correlates with the perceived quality of SR images.