Title
EMScore: Evaluating Video Captioning via Coarse-Grained and Fine-Grained Embedding Matching
Abstract
Current metrics for video captioning are mostly based on the text-level comparison between reference and candidate captions. However, they have some insuperable drawbacks, e.g., they cannot handle videos without references, and they may result in biased evaluation due to the one-to-many nature of video-to-text and the neglect of visual relevance. From the human evaluator's viewpoint, a high-quality caption should be consistent with the provided video, but not necessarily be similar to the reference in literal or semantics. Inspired by human evaluation, we propose EMScore (Embedding Matching-based score), a novel reference-free metric for video captioning, which directly measures similarity between video and candidate captions. Benefiting from the recent development of large-scale pre-training models, we exploit a well pre-trained vision-language model to extract visual and linguistic embeddings for computing EMScore. Specifically, EMScore combines matching scores of both coarse-grained (video and caption) and fine-grained (frames and words) levels, which takes the overall understanding and detailed characteristics of the video into account. Furthermore, considering the potential information gain, EMScore can be flexibly extended to the conditions where human-labeled references are available. Last but not least, we collect VATEX-EVAL and ActivityNet-FOIl datasets to systematically evaluate the existing metrics. VATEX-EVAL experiments demonstrate that EMScore has higher human correlation and lower reference dependency. ActivityNet-FOIL experiment verifies that EMScore can effectively identify “hallucinating” captions. Code and datasets are available at https://github.com/shiyaya/emscore.
Year
DOI
Venue
2022
10.1109/CVPR52688.2022.01740
IEEE Conference on Computer Vision and Pattern Recognition
Keywords
DocType
Volume
Vision + language
Conference
2022
Issue
Citations 
PageRank 
1
0
0.34
References 
Authors
0
7
Name
Order
Citations
PageRank
Yaya Shi100.34
Xu Yang200.34
Haiyang Xu362.48
Chunfeng Yuan441830.84
Bing Li521760.28
Weiming Hu65300261.38
Zheng-Jun Zha700.34