The BCC Matte Choker filter is a tool for the often frustrating task of adjusting mattes that are not quite right. A first-pass matte often has unwanted holes in areas that should be opaque, and/or unwanted spots in areas that should be transparent. These problems can usually be fixed with Matte Choker.
BCC Matte Choker uses an iterative technique to process the source alpha channel. In other words, the filter applies one stage of the process to the source image, then applies a second stage to the output of the first stage, and repeats the process using the output of each iteration as the input of the next.