SmartGrid: Video Retargeting With Spatiotemporal Grid Optimization

We propose SmartGrid, a new video-retargeting method that preserves a shape of the salient object and maintains a temporal coherence for the static background regions in the video. Previous methods mainly focus on preserving the shape of the salient object or maintaining the temporal coherence for each region. However, these methods do not explicitly adjust the sizes of the grids corresponding to the salient objects and the static background regions. Thus, they have difficulty in maintaining the consistency of the salient object shape and the temporal coherence for the static background regions. The basic idea of SmartGrid is to maintain the consistency of the contents in consecutive frames by analyzing the degree of the spatiotemporal consistency. Compared to the best results obtained using eight previous methods, SmartGrid achieved improvements of 1.19× in Bidirectional Similarity Measure, 7.59× in Jittery Metric 1, and 13.16× in Jittery Metric 2, and reduced the average computation time per pixel by 6.14×.