Objective quality assessment of medical images and videos : review and challenges

Quality assessment is a key element for the evaluation of hardware and software involved in
image and video acquisition, processing, and visualization. In the medical field, user-based
quality assessment is still considered more reliable than objective methods, which allow the
implementation of automated and more efficient solutions. Regardless of increasing research
on this topic in the last decade, defining quality standards for medical content remains a nontrivial task, as the focus should be on the diagnostic value assessed by expert viewers rather
than the perceived quality from naïve viewers, and objective quality metrics should aim at
estimating the first rather than the latter. In this paper, we present a survey of methodologies
used for the objective quality assessment of medical images and videos, dividing them into
visual quality-based and task-based approaches. Visual quality-based methods compute a
quality index directly from visual attributes, while task-based methods, being increasingly
explored, measure the impact of quality impairments on the performance of a specific task. A
discussion on the limitations of state-of-the-art research on this topic is also provided, along
with future challenges to be addressed.