A patch-based contraction process for the improvement of image matting
In this paper, we propose a patch-based contraction process for the improvement of image matting. Given an input image and a trimap, the proposed contraction process quickly refines the trimap by reclassifying the alpha values of the undetermined pixels into “foreground”, “background”, or “undetermined”, based on the feature similarity of the undetermined pixels with respect to the foreground/background regions. The refinement of trimap causes the shrinkage of undetermined regions and may reveal more foreground/background information across isolated regions. Based on the refined trimap, the image matting algorithm can better estimate the alpha values of the image. Experimental results show that the proposed patch-based process provides an effective and efficient way to obtain a refined trimap and the use of the trimap refinement improves the performance of image matting.