A low complexity wavelet transform with point-symmetric extension at tile boundaries

This paper presents a low-complexity wavelet transform that utilizes the point-symmetric extension at the image tile boundaries. The proposed solution preserves the perfect reconstruction property of the filter banks and deals efficiently with the blocking artifacts when images are lossy compressed. It is shown that the point-symmetric extension at the tile boundaries does not need to be applied explicitly, but instead the equivalent boundary filters can be derived. The lifting-based implementation of the filters provides a very simple way of changing filter parameters at the boundaries that suits both hardware and software platforms A new architecture is proposed to perform wavelet transform of large images. It minimizes the DSPs internal memory requirements as well as the external buffer bandwidth without producing sharp discontinuities between tiles.