Compression at low bitrates in modern codecs often introduces banding artifacts, especially in smooth regions such as skies. These artifacts degrade visual quality and are common in user-generated content due to repeated transcoding. We propose a banding restoration method that employs the Wavelet State Space Model and a frequency masking map to preserve high-frequency details. Furthermore, we provide a benchmark of open-source banding restoration methods and evaluate their performance on two public banding image datasets. Experimentation on the available datasets suggests that the proposed post-processing approach effectively suppresses banding compared to the state-of-the-art method (a DBI value of 0.082 on BAND-2k) while preserving image textures. Visual inspections of the results confirm this. Code and supplementary material are available at: https://github.com/xinyiW915/Debanding-PCS2025.

翻译：现代编解码器在低比特率压缩时，尤其在天空等平滑区域中，常引入条带伪影。这些伪影会降低视觉质量，并且由于重复转码，在用户生成内容中十分常见。我们提出了一种条带恢复方法，该方法利用小波状态空间模型和频率掩码图来保留高频细节。此外，我们建立了一个开源条带恢复方法的基准，并在两个公开的条带图像数据集上评估了它们的性能。在现有数据集上的实验表明，与最先进的方法相比（在BAND-2k数据集上DBI值为0.082），所提出的后处理方案能有效抑制条带，同时保留图像纹理。结果的可视化检查证实了这一点。代码及补充材料可在以下网址获取：https://github.com/xinyiW915/Debanding-PCS2025。