Combining the Advantages of Local and Global Optic Flow Methods

Differential methods are frequently used techniques for optic flow computations. They can be classified into local methods such as the Lucas–Kanade technique or Bigün’s structure tensor method, and into global methods such as the Horn–Schunck approach and its modifications. Local methods are known to be more robust under noise, while global techniques yield 100% dense flow fields. No clear attempts to combine the advantages of these two classes of methods have been made in the literature so far. This problem is addressed in our paper. First we juxtapose the role of smoothing processes that are required in local and global differential methods for optic flow computation. This discussion motivates us to introduce and evaluate a novel method that combines the advantages of local and global approaches: It yields dense flow fields that are robust against noise. Finally experiments with different sequences are performed demonstrating its excellent results.