  We present a multimodal traffic light state detection using vision and sound,
from the viewpoint of a quadruped robot navigating in urban settings. This is a
challenging problem because of the visual occlusions and noise from robot
locomotion. Our method combines features from raw audio with the ratios of red
and green pixels within bounding boxes, identified by established vision-based
detectors. The fusion method aggregates features across multiple frames in a
given timeframe, increasing robustness and adaptability. Results show that our
approach effectively addresses the challenge of visual occlusion and surpasses
the performance of single-modality solutions when the robot is in motion. This
study serves as a proof of concept, highlighting the significant, yet often
overlooked, potential of multi-modal perception in robotics.
