YES NO Cartesian Update Update Feature Extraction Feature Extraction Phase Correlation Resample Min Eq . 3 ? Fourier spaceLog-Polar Cross Correlation Model Fourier space Model Sample Sample

Most of existing correlation filter-based tracking approaches only estimate simple axis-aligned bounding boxes, and very few of them is capable of recovering the underlying similarity transformation. To a large extent, such limitation restricts the applications of such trackers for a wide range of scenarios. In this paper, we propose a novel correlation filter-based tracker with robust estimation of similarity transformation on the large displacements to tackle this challenging problem. In order to efficiently search in such a large 4-DoF space in real-time, we formulate the problem into two 2-DoF sub-problems and apply an efficient Block Coordinates Descent solver to optimize the estimation result. Specifically, we employ an efficient phase correlation scheme to deal with both scale and rotation changes simultaneously in log-polar coordinates. Moreover, a fast variant of correlation filter is used to predict the translational motion individually. Our experimental results demonstrate that the proposed tracker achieves very promising prediction performance compared with the state-of-the-art visual object tracking methods while still retaining the advantages of efficiency and simplicity in conventional correlation filter-based tracking methods.