arXiv Computer Vision
Aug 31

NumBench: Diagnosing Counting Failures in Text-to-Image Models

NumBench is a large benchmark of 640,000 text‑to‑image prompts that tests how well models count objects, covering 1,600 categories and counts from 1 to 100. It uses a factorial design to vary composition, spatial guidance, and appearance while balancing counts, and introduces a process model that predicts a near‑quadratic collision deficit at low occupancy. The authors also propose the Confidence‑Weighted Numeric Precision Score for scalable evaluation and find that all tested systems perform poorly above 50 objects, with count range, layout, and composition having the largest effects.

By Sandeep Wadhwa, Mayank Vatsa, Richa Singh, Parrva Chirag Shah, Prakhar Galriya
arXiv Computer Vision
Oct 1

SYNCR: A Cross-Video Reasoning Benchmark with Synthetic Grounding

SYNCR is a synthetic benchmark designed to evaluate multimodal large language models on cross‑video reasoning. It contains 4,000 question‑answer pairs across 4,827 unique videos, covering tasks in temporal alignment, spatial tracking, comparative reasoning, and holistic synthesis. The benchmark reveals a significant performance gap between current models and humans, with models excelling at temporal ordering but struggling with precise physical and spatial reasoning.

By Sara Ghazanfari, Siddharth Garg, Prashanth Krishnamurthy, Farshad Khorrami
arXiv AI
Sep 21

VidOmni-Bench: A Benchmark for Fine-Grained Video Understanding via Spatio-Temporal Event Verification across Complexity and Duration

VidOmni-Bench is a new benchmark for fine‑grained video understanding that asks models to verify whether each event in dense video captions is supported by the video. It contains 500 videos covering five complexity types and durations from 4 seconds to 90 minutes, and uses human‑verified sentence‑level labels to create hard negatives. Experiments show that Video‑LLMs often hallucinate events, struggle to detect incorrect descriptions, and exhibit varying weaknesses depending on video complexity and duration.

By Changbeen Kim, Junwon Chang, Kipyo Kim, Risa Shinoda, Kuniaki Saito, Donghyun Kim