Semantics-Guided Multimodal Masked Autoencoder Pretraining for 3D BEV Object Detection

Fuente: arXiv
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Auteurs principaux: Wariyapperuma, Prabuddhi, de Silva, Rajitha, Hanheide, Marc, Bohné, Thomas, Guevara, Leonardo
Format: Preprint
Publié: 2026
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author Wariyapperuma, Prabuddhi
de Silva, Rajitha
Hanheide, Marc
Bohné, Thomas
Guevara, Leonardo
author_facet Wariyapperuma, Prabuddhi
de Silva, Rajitha
Hanheide, Marc
Bohné, Thomas
Guevara, Leonardo
contents Accurate 3D bird's-eye view (BEV) object detection is essential for autonomous driving, and depends strongly on effective multimodal representations from complementary sensors such as cameras and LiDAR. Multimodal masked autoencoders have shown strong potential for learning such representations for downstream 3D BEV object detection. However, existing methods typically apply uniform random masking to camera and LiDAR inputs, treating all regions equally, and learn representations only through masked reconstruction. We propose a semantics-guided multimodal masked autoencoder framework that introduces semantic information during pretraining through two separate components: (i) semantics-guided LiDAR voxel masking, which preserves semantically important LiDAR regions more strongly, and (ii) an auxiliary point-wise LiDAR semantic decoder branch that injects semantic guidance in addition to reconstruction. On BEVFusion 3D object detection, our semantics-guided pretraining strategy improves performance on the nuScenes mini validation set compared to the standard UniM2AE baseline: semantics-guided LiDAR voxel masking yields +1.49% mean Average Precision (mAP) and +1.66% nuScenes Detection Score (NDS), while decoder-side point semantic supervision yields +1.39% mAP and +3.22% NDS over the baseline.
format Preprint
id arxiv_https___arxiv_org_abs_2605_25262
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Semantics-Guided Multimodal Masked Autoencoder Pretraining for 3D BEV Object Detection
Wariyapperuma, Prabuddhi
de Silva, Rajitha
Hanheide, Marc
Bohné, Thomas
Guevara, Leonardo
Computer Vision and Pattern Recognition
Accurate 3D bird's-eye view (BEV) object detection is essential for autonomous driving, and depends strongly on effective multimodal representations from complementary sensors such as cameras and LiDAR. Multimodal masked autoencoders have shown strong potential for learning such representations for downstream 3D BEV object detection. However, existing methods typically apply uniform random masking to camera and LiDAR inputs, treating all regions equally, and learn representations only through masked reconstruction. We propose a semantics-guided multimodal masked autoencoder framework that introduces semantic information during pretraining through two separate components: (i) semantics-guided LiDAR voxel masking, which preserves semantically important LiDAR regions more strongly, and (ii) an auxiliary point-wise LiDAR semantic decoder branch that injects semantic guidance in addition to reconstruction. On BEVFusion 3D object detection, our semantics-guided pretraining strategy improves performance on the nuScenes mini validation set compared to the standard UniM2AE baseline: semantics-guided LiDAR voxel masking yields +1.49% mean Average Precision (mAP) and +1.66% nuScenes Detection Score (NDS), while decoder-side point semantic supervision yields +1.39% mAP and +3.22% NDS over the baseline.
title Semantics-Guided Multimodal Masked Autoencoder Pretraining for 3D BEV Object Detection
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2605.25262