Learning quality assessment of retargeted images

Content-aware image resizing (or image retargeting) enables images to be fit to different display devices having different aspect ratios while preserving salient image content. There are many approaches to retargeting, although no “best” method has been agreed upon. Therefore, finding ways to assess the quality of image retargeting has become a prominent challenge. Traditional image quality assessment methods are not directly applicable to image retargeting because the retargeted image size is not same as the original one. In this paper, we propose an open framework for image retargeting quality assessment, where the quality prediction engine is a trained Radial Basis Function (RBF) neural network. Broadly, our approach is motivated by the observation that no single method can be expected to perform well on all types of content. We train the network on ten perceptually relevant features, including a saliency-weighted, SIFT-directed complex wavelet structural similarity (CW-SSIM) index, and a new image aesthetics evaluation method. These two features and eight other features are used by the neural network to learn to assess the quality of retargeted images. The accuracy of the new model is extensively verified by simulations.