Salient object detection with low-rank approximation and ℓ2,1-norm minimization

Abstract

Salient object detection is an important issue in computer vision and image procession in that it can facilitate humans to locate conspicuous visual regions in complex scenes rapidly and improve the performance of object detection and video tracking. In recent years, low-rank matrix approximation has been proved to be favorable in image saliency detection and gained a great deal of attention. An underlying assumption of low-rank recovery is that an image is a combination of background regions being low-rank and salient objects being sparse, which corresponds to tough non-smooth optimization problems. In this paper, by incorporating ℓ2,1-norm minimization, we obtain the corresponding smooth optimization problems and propose two effective algorithms with proved convergence. To guarantee the robustness of the proposed methods, the input image is divided into patches and each patch is approximately represented by its mean value. Besides, multi-scale visual features of each patch of the given image are extracted to capture common low-level features such as color, edge, shape and texture. The salient objects of a given image are indicated with sparse coefficients solved by the low-rank matrix approximation problem. Saliency maps are further produced with integration of the high-level prior knowledge. Finally, extensive experiments in four real-world datasets demonstrate that the proposed methods come with competitive performance over the eight compared state-of-the-arts.