Yepeng Zhang
Author directory2026
Depth as Verifiable Geometric Feedback: Enhancing Spatial Reasoning in Multimodal Large Language Models
Yepeng Zhang | Ruohang Xu | Zihao Yue | Boshen Xu | Qin Jin
Findings of the Association for Computational Linguistics: EMNLP 2026
Yepeng Zhang | Ruohang Xu | Zihao Yue | Boshen Xu | Qin Jin
Findings of the Association for Computational Linguistics: EMNLP 2026
Multimodal large language models (MLLMs) still struggle with spatial reasoning, particularly on tasks requiring consistent geometric understanding across multiple image regions. While recent works incorporate depth supervision into MLLMs, it remains unclear what forms of geometric learning are most beneficial for spatial reasoning transfer. In this work, we propose Multi-point Geometric Consistency Alignment (MGCA), a geometry-guided post-training framework that uses depth annotations as verifiable geometric feedback without requiring depth input at inference time. MGCA samples multiple image regions and optimizes the model through a unified geometric reward that jointly captures metric grounding and relative geometric consistency. Specifically, the reward combines a metric depth objective with a margin-aware ranking objective and is optimized via Group Relative Policy Optimization (GRPO). Experiments on multiple spatial reasoning benchmarks show that MGCA consistently improves spatial understanding and outperforms comparable open-weight MLLMs of similar scale. More importantly, our analysis reveals that optimizing relative ordering alone can achieve high ranking accuracy while failing to learn transferable geometric representations due to the lack of metric grounding. In contrast, jointly optimizing metric depth and relational consistency leads to substantially stronger spatial reasoning performance. These findings suggest that effective spatial alignment in MLLMs requires metrically grounded relational learning, rather than relation-only supervision.
2025
Movie101v2: Improved Movie Narration Benchmark
Zihao Yue | Yepeng Zhang | Ziheng Wang | Qin Jin
Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Zihao Yue | Yepeng Zhang | Ziheng Wang | Qin Jin
Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Automatic movie narration aims to generate video-aligned plot descriptions to assist visually impaired audiences. Unlike standard video captioning, it involves not only describing key visual details but also inferring plots that unfold across multiple movie shots, presenting distinct and complex challenges. To advance this field, we introduce Movie101v2, a large-scale, bilingual dataset with enhanced data quality specifically designed for movie narration. Revisiting the task, we propose breaking down the ultimate goal of automatic movie narration into three progressive stages, offering a clear roadmap with corresponding evaluation metrics. Based on our new benchmark, we baseline a range of large vision-language models and conduct an in-depth analysis of the challenges in movie narration generation. Our findings highlight that achieving applicable movie narration generation is a fascinating goal that requires significant research.