Excavating the Most Critical Gaussians: Sparse Selection and Structural Optimization for Efficient 3DGS Compression

3D Gaussian Splatting (3DGS) has emerged as a promising framework for real-time radiance field rendering due to its high fidelity and explicit scene modeling. However, its practical deployment in the multimedia domain remains limited by excessive memory usage stemming from redundant and memory-inefficient Gaussian primitives. In this paper, we propose SOC-GS, a novel compression framework that enhances the anchor-based 3DGS representation through perceptually guided and structural optimization. Specifically, we begin by introducing the Perceptual Relevance Score (PRS), with a Gumbel noise perturbation applied to facilitate sparse Top-K selection of Gaussians critical for densification, significantly reducing the number of anchors. Further, we stabilize training and prevent premature overfitting the high-frequency noise using a Joint Resolution-Blur Training strategy, with guidance from Total Variation Loss, enabling coarse-to-fine learning with the consistency of spatial distribution throughout training. Finally, a Spatial Condition-based Prediction module is employed to further reduce storage while preserving comparable quality. Extensive experiments on three benchmark datasets demonstrate that our method achieves an average of 34% reduction in model size when compared to existing state-of-the-art compression method (126 × compression on vanilla 3DGS), while maintaining comparable--or even superior--rendering quality.