Encoding Auxiliary Information to Restore Compressed Point Cloud Geometry

摘要

The standardized Geometry-based Point Cloud Compression (G-PCC) suffers from limited coding performance and low-quality reconstruction. To address this, we propose AuxGR, a performance-complexity tradeoff solution for point cloud geometry restoration: leveraging auxiliary bitstream to enhance the quality of G-PCC compressed point cloud geometry. This auxiliary bitstream efficiently encapsulates spatio-temporal information. For static coding, we perform paired information embedding (PIE) on the G-PCC decoded frame by employing target convolutions from its original counterpart, producing an auxiliary bitstream containing abundant original information. For dynamic coding, in addition to PIE, we propose temporal information embedding (TIE) to capture motion information between the previously restored and the current G-PCC decoded frames. TIE applies target kNN attention between them, which ensures the temporal neighborhood construction for each point and implicitly represents motions. Due to the similarity across temporal frames, only the residuals between TIE and PIE outputs are compressed as auxiliary bitstream. Experimental results demonstrate that AuxGR notably outperforms existing methods in both static and dynamic coding scenarios. Moreover, our framework enables the flexible incorporation of auxiliary information under computation constraints, which is attractive to real applications.