GaussianOcc3D: A Gaussian-Based Adaptive Multi-modal 3D Occupancy Prediction
A. Enes Doruk, Hasan F. Ates
TL;DR
GaussianOcc3D addresses dense 3D semantic occupancy prediction by fusing camera semantics and LiDAR geometry within a memory-efficient shared Gaussian space. It introduces four modules—LDFA for LiDAR lifting, EBFS for cross-modal smoothing, ACLF for adaptive fusion, and Gauss-Mamba Head for global context—to jointly learn Gaussian primitives and predict a voxelized occupancy grid. The approach achieves state-of-the-art mIoU on Occ3D (49.4%), SurroundOcc (28.9%), and SemanticKITTI (25.2%), while maintaining robustness under rain and nighttime conditions. By operating on continuous Gaussian primitives rather than voxel grids, GaussianOcc3D reduces computational burden and preserves high-fidelity geometry and semantics, enabling reliable 3D scene understanding for autonomous driving.
Abstract
3D semantic occupancy prediction is a pivotal task in autonomous driving, providing a dense and fine-grained understanding of the surrounding environment, yet single-modality methods face trade-offs between camera semantics and LiDAR geometry. Existing multi-modal frameworks often struggle with modality heterogeneity, spatial misalignment, and the representation crisis--where voxels are computationally heavy and BEV alternatives are lossy. We present GaussianOcc3D, a multi-modal framework bridging camera and LiDAR through a memory-efficient, continuous 3D Gaussian representation. We introduce four modules: (1) LiDAR Depth Feature Aggregation (LDFA), using depth-wise deformable sampling to lift sparse signals onto Gaussian primitives; (2) Entropy-Based Feature Smoothing (EBFS) to mitigate domain noise; (3) Adaptive Camera-LiDAR Fusion (ACLF) with uncertainty-aware reweighting for sensor reliability; and (4) a Gauss-Mamba Head leveraging Selective State Space Models for global context with linear complexity. Evaluations on Occ3D, SurroundOcc, and SemanticKITTI benchmarks demonstrate state-of-the-art performance, achieving mIoU scores of 49.4%, 28.9%, and 25.2% respectively. GaussianOcc3D exhibits superior robustness across challenging rainy and nighttime conditions.
