Grounding Plural Phrases: Countering Evaluation Biases by Individuation

Julia Suter, Letitia Parcalabescu, Anette Frank


Abstract
Phrase grounding (PG) is a multimodal task that grounds language in images. PG systems are evaluated on well-known benchmarks, using Intersection over Union (IoU) as evaluation metric. This work highlights a disconcerting bias in the evaluation of grounded plural phrases, which arises from representing sets of objects as a union box covering all component bounding boxes, in conjunction with the IoU metric. We detect, analyze and quantify an evaluation bias in the grounding of plural phrases and define a novel metric, c-IoU, based on a union box’s component boxes. We experimentally show that our new metric greatly alleviates this bias and recommend using it for fairer evaluation of plural phrases in PG tasks.
Anthology ID:
2021.alvr-1.4
Volume:
Proceedings of the Second Workshop on Advances in Language and Vision Research
Month:
June
Year:
2021
Address:
Online
Editors:
Xin, Ronghang Hu, Drew Hudson, Tsu-Jui Fu, Marcus Rohrbach, Daniel Fried
Venue:
ALVR
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
22–28
Language:
URL:
https://aclanthology.org/2021.alvr-1.4
DOI:
10.18653/v1/2021.alvr-1.4
Bibkey:
Cite (ACL):
Julia Suter, Letitia Parcalabescu, and Anette Frank. 2021. Grounding Plural Phrases: Countering Evaluation Biases by Individuation. In Proceedings of the Second Workshop on Advances in Language and Vision Research, pages 22–28, Online. Association for Computational Linguistics.
Cite (Informal):
Grounding Plural Phrases: Countering Evaluation Biases by Individuation (Suter et al., ALVR 2021)
Copy Citation:
PDF:
https://aclanthology.org/2021.alvr-1.4.pdf