[OPTICAL REVIEW Vol. 19, No. 5 (2012) 349-354]
© 2012 The Japan Society of Applied Physics

Combined Image Similarity Index

Krzysztof OKARMA*

Department of Signal Processing and Multimedia Engineering, West Pomeranian University of Technology, Szczecin, ul. 26. Kwietnia 10, 71-126, Szczecin, Poland

(Received December 21, 2011; Accepted June 27, 2012)

In the paper the idea of the combined image quality metric based on the structural and feature similarity comparison is discussed. Since most of image quality assessment methods developed during last years require the nonlinear mapping to obtain high correlation with subjective quality scores, there is an important problem of choosing the proper mapping function and its optimal parameters in practical applications. The most common approach is the utilization of the logistic function but its parameters strongly depend on the specific image quality database. To avoid the necessity of such mapping the nonlinear combination of three known image quality metrics is proposed and verified for seven currently available image quality assessment databases in terms of the linear correlation with subjective scores.

Key words: image quality assessment, image similarity, structural similarity

*E-mail address: okarma@zut.edu.pl