1. Introduction
Image saliency detection aims to effectively identify important and informative regions in images. Early approaches in this area focus mainly on predicting where humans look, and thus work only on human eye fixation data [1]–[3]. Recently, a large body of work concentrates on salient object detection [4]–[17], whose goal is to discover the most salient and attention-grabbing object in an image. This has a wide range of applications such as image retargeting [18], image classification [19], and image segmentation [20], [21]. Because it is difficult to define saliency analytically, the performance of salient object detection is evaluated on datasets containing human-labeled bounding boxes or foreground masks.