ResNeRF-PCAC: Super Resolving Residual Learning NeRF for High Efficiency Point Cloud Attributes Coding

A point cloud (PC) is a popular 3D data representation that poses challenges due to its size, dimensionality, and unstructured nature. This paper introduces the Residual Neural Radiance Field for Point Cloud Attribute Coding (ResNeRFPCAC), a novel approach for point cloud attribute compression. ResNeRF-PCAC combines sparse convolutions with neural radiance fields, to create a highly efficient attribute coding solution. It initially downscales the point cloud to generate a coarse thumbnail point cloud and encodes it using the G-PCC attribute encoder. The thumbnail PC is upsampled using a super-resolution network to generate a recolored PC. Color attribute residuals are then computed between the original and the super-resolved recolored PC. A ResNeRF network is employed to predict these residuals. The trained ResNeRF weights are compressed into a bitstream. The thumbnail bitstream and the compressed model weights are then transmitted to the decoder. Sparse convolution-based super-resolving network weights are shared and common across all content and need not to be signaled. Experiments on the MPEG-8i dataset demonstrate superior performance in terms of reconstruction quality and compression ratio compared to G-PCCRAHT and G-PCC-Predlift for both v14 and v21.