HiLM-D: Towards High-Resolution Understanding in Multimodal Large Language Models for Autonomous Driving

Autonomous driving systems generally employ separate models for different tasks resulting in intricate designs. For the first time, we leverage singular multimodal large language models (MLLMs) to consolidate multiple autonomous driving tasks from videos, i.e., the Risk Object Localization and Intention and Suggestion Prediction (ROLISP) task. ROLISP uses natural language to simultaneously identify and interpret risk objects, understand ego-vehicle intentions, and provide motion suggestions, eliminating the necessity for task-specific architectures. However, lacking high-resolution (HR) information, existing MLLMs often miss small objects (e.g., traffic cones) and overly focus on salient ones (e.g., large trucks) when applied to ROLISP. We propose HiLM-D (Towards High-Resolution Understanding in MLLMs for Autonomous Driving), an efficient method to incorporate HR information into MLLMs for the ROLISP task. Especially, HiLM-D integrates two branches: (i) the low-resolution reasoning branch, can be any MLLMs, processes low-resolution videos to caption risk objects and discern ego-vehicle intentions/suggestions; (ii) the high-resolution perception branch (HR-PB), prominent to HiLM-D,, ingests HR images to enhance detection by capturing vision-specific HR feature maps and prioritizing all potential risks over merely salient objects. Our HR-PB serves as a plug-and-play module, seamlessly fitting into current MLLMs. Experiments on the ROLISP benchmark reveal HiLM-D's notable advantage over leading MLLMs, with improvements of 4.8% in BLEU-4 for captioning and 17.2% in mIoU for detection.