ABSTRACT
This chapter presents work on a no-reference objective quality metric (NROQM) that has resulted from extensive research on impairment metrics, image feature metrics, and subjective image quality in several projects in Philips Research, and participation in the International Telecommunication Union Video Quality Experts Group. It provides a summary of the state-of-the-art and discusses the objective image quality metric design process and its components. The components of the NROQM are measures of image features which can be computed directly without using the original image. The combined assessment of desirable and non-desirable features is expected to be a reasonable indicator of overall image quality as perceived on the average by human subjects. Clipping is a truncation in the number of bits of the image values imposed by the arithmetic precision of the process being used. Noise is a random variation in the spatial or temporal dimension, which appears in video images as a result of random processes linked to transmission and generation techniques.
