  Banding artifacts, which manifest as staircase-like color bands on pictures
or video frames, is a common distortion caused by compression of low-textured
smooth regions. These false contours can be very noticeable even on
high-quality videos, especially when displayed on high-definition screens. Yet,
relatively little attention has been applied to this problem. Here we consider
banding artifact removal as a visual enhancement problem, and accordingly, we
solve it by applying a form of content-adaptive smoothing filtering followed by
dithered quantization, as a post-processing module. The proposed debanding
filter is able to adaptively smooth banded regions while preserving image edges
and details, yielding perceptually enhanced gradient rendering with limited
bit-depths. Experimental results show that our proposed debanding filter
outperforms state-of-the-art false contour removing algorithms both visually
and quantitatively.
