Multi-modal fusion of sensors is a commonly used approach to enhance the
performance of odometry estimation, which is also a fundamental module for
mobile robots. However, the question of \textit{how to perform fusion among
different modalities in a supervised sensor fusion odometry estimation task?}
is still one of challenging issues remains. Some simple operations, such as
element-wise summation and concatenation, are not capable of assigning adaptive
attentional weights to incorporate different modalities efficiently, which make
it difficult to achieve competitive odometry results. Recently, the Transformer
architecture has shown potential for multi-modal fusion tasks, particularly in
the domains of vision with language. In this work, we propose an end-to-end
supervised Transformer-based LiDAR-Inertial fusion framework (namely
TransFusionOdom) for odometry estimation. The multi-attention fusion module
demonstrates different fusion approaches for homogeneous and heterogeneous
modalities to address the overfitting problem that can arise from blindly
increasing the complexity of the model. Additionally, to interpret the learning
process of the Transformer-based multi-modal interactions, a general
visualization approach is introduced to illustrate the interactions between
modalities. Moreover, exhaustive ablation studies evaluate different
multi-modal fusion strategies to verify the performance of the proposed fusion
strategy. A synthetic multi-modal dataset is made public to validate the
generalization ability of the proposed fusion strategy, which also works for
other combinations of different modalities. The quantitative and qualitative
odometry evaluations on the KITTI dataset verify the proposed TransFusionOdom
could achieve superior performance compared with other related works.

本研究中，我们提出了一个基于 Transformer 的 LiDAR-Inertial 融合（即 TransFusionOdom）的端到端受监督的 odom 估计框架，用于解决传感器融合中的挑战性问题。我们提出的多注意力融合模块可展示多种同构和异构融合策略，以解决盲目增加模型复杂性带来的过拟合问题，而且使用了一种通用的可视化方法来说明基于 Transformer 的多模态交互学习过程。我们公开了一个综合多模态数据集以验证传感器融合贡献的通用性，并在 KITTI 数据集上进行了定量和定性 odom 评估，结果表明与其他相关工作相比，我们提出的 TransFusionOdom 具有更好的性能。