How does image content affect the added value of visual attention in objective image quality assessment?

Our previous research has demonstrated that adding natural scene saliency (NSS) obtained from eye-tracking data may improve an objective metric's performance in predicting perceived image quality. In this letter, we further investigate the image content dependency of this improvement. Results show that the variation in saliency between observers highly depends on image content, and that this variation predicts the extent to which a certain image may profit from adding saliency in the objective image quality assessment