Adaptive trimap propagation for video matting

摘要

Methods and apparatus for adaptive trimap propagation. Methods are described that allow a trimap to be propagated from one frame to the next in a temporally coherent way. A radius-based method propagates automatically computed local trimap radii from frame to frame. A mesh-based method employs pins on the binary segmentation boundary and a mesh generated for the unknown region; the pins are tracked from one frame to the next according to an optical flow technique, the mesh is deformed from one frame to the next according to the movement of the pins, and the adaptive trimap is then warped according to the deformed mesh. These methods can be used separately, or the first method can be used to propagate some regions of the adaptive trimap, and the second method can be used to propagate other regions of the adaptive trimap.

主权项

1. A method, comprising:
performing, by one or more computing devices: obtaining a trimap for a frame in an image sequence comprising a plurality of frames, the trimap indicating a segmentation of an image in the frame into a known foreground region, a known background region, and an unknown region comprising the area between the foreground region and the background region; propagating the unknown region for the frame to a next frame in the image sequence according to optical flow information indicating movement of image content between the frame and the next frame, the propagating of the unknown region according to optical flow information includes: determining, for each of a plurality of portions of the unknown region, which of a warp-based technique and a radius-based technique to use; and using, for each of the plurality of portions of the unknown region, the technique determined for the portion to propagate the portion from the frame to the next frame; and generating a trimap for the next frame according to the propagated unknown region.