Motion Layer Segmentation and Matting
Given a video sequence, obtaining accurate layer segmentation and alpha matting is very important for various applications. However, when a non-textured or smooth area is present in the scene, the segmentation based on only single motion cue usually cannot provide satisfactory results. Conversely, the most matting approaches require a smooth assumption on foreground and background to obtain a good result. In this paper, we combine the merits of motion segmentation and alpha matting technique together to simultaneously achieve high-quality layer segmentation and alpha mattes. First, we explore a general occlusion constraint and design a novel graph cuts framework to solve the layer-based motion segmentation problem for the textured regions using multiple frames. Then, an alpha matting technique is further used to refine the segmentation and resolve the non-textured ambiguities by determining proper alpha values for the foreground and background respectively.
Figure 1: Multi-frame segmentation for a two-layer synthetic image sequence. Top: several black lines, two ellipses, and one triangle is moving form top-right to bottom-left on a random fixed background. (a) The results obtained using our previous algorithm with the occlusion order constraint, where the pixels (red) occluded between frame 1 and 2 will be always occluded between frame 1 and j (j > 2). (b) The correct results by our approach using frame 1 as the reference image. (c) The correct results by our approach using frame 3 as the reference image.
Figure 1: The results of flower-garden sequence. (a) Original images. (b) Segmentation results before applying matting process. (c) Alpha matting results. (d) Segmentation results after matting process. (e) Object transfer after superimposing
the foreground of flower-garden in another video sequence.
Jiangjian Xiao and Mubarak Shah, “Accurate Motion Layer Segmentation and Matting”, IEEE Conference on Computer Vision and Pattern Recognition, June 20-26, San Diego, 2005.
Jiangjian Xiao and Mubarak Shah, “Motion Layer Extraction in the Presence of Occlusion using Graph Cut”, IEEE transactions on Pattern Analysis and Machine Intelligence, Vol. 27, No. 10, pp. 1644-1659, 2005