We present an effective image boundary processing for M-channel (M ∈ IN, M ≥ 2) lifting-based linear-phase filter banks that are applied to unified lossy and lossless image compression (coding), i.e., lossy-to-lossless image coding. The reversible symmetric extension we propose is achieved by manipulating building blocks on the image boundary and reawakening the symmetry of each building block that has been lost due to rounding error on each lifting step. In addition, complexity is reduced by extending nonexpansive convolution, called reversible symmetric nonexpansive convolution, because the number of input signals does not even temporarily increase. Our method not only achieves reversible boundary processing, but also is comparable with irreversible symmetric extension in lossy image coding and outperformed periodic extension in lossy-to-lossless image coding.

中文翻译：

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可逆对称非膨胀卷积：基于M通道提升的线性相位滤波器组的有效图像边界处理。

我们提出了一种针对基于M通道（M∈IN，M≥2）提升的线性相位滤波器组的有效图像边界处理，该滤波器组适用于统一的有损和无损图像压缩（编码），即有损至无损图像编码。我们提出的可逆对称扩展是通过在图像边界上操纵构造块并重新唤醒由于每个提升步骤中的舍入误差而丢失的每个构造块的对称性来实现的。另外，由于输入信号的数量甚至不会暂时增加，因此通过扩展称为可逆对称非膨胀卷积的非膨胀卷积可以降低复杂度。我们的方法不仅实现了可逆边界处理，