Color histogram equalization and fine-tuning to improve expression recognition of (partially occluded) faces on sign language datasets

Fuente: arXiv
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Hauptverfasser: Nunnari, Fabrizio, Singh, Alakshendra Jyotsnaditya Ramkrishna, Gebhard, Patrick
Format: Preprint
Veröffentlicht: 2025
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author Nunnari, Fabrizio
Singh, Alakshendra Jyotsnaditya Ramkrishna
Gebhard, Patrick
author_facet Nunnari, Fabrizio
Singh, Alakshendra Jyotsnaditya Ramkrishna
Gebhard, Patrick
contents The goal of this investigation is to quantify to what extent computer vision methods can correctly classify facial expressions on a sign language dataset. We extend our experiments by recognizing expressions using only the upper or lower part of the face, which is needed to further investigate the difference in emotion manifestation between hearing and deaf subjects. To take into account the peculiar color profile of a dataset, our method introduces a color normalization stage based on histogram equalization and fine-tuning. The results show the ability to correctly recognize facial expressions with 83.8% mean sensitivity and very little variance (.042) among classes. Like for humans, recognition of expressions from the lower half of the face (79.6%) is higher than that from the upper half (77.9%). Noticeably, the classification accuracy from the upper half of the face is higher than human level.
format Preprint
id arxiv_https___arxiv_org_abs_2507_20197
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Color histogram equalization and fine-tuning to improve expression recognition of (partially occluded) faces on sign language datasets
Nunnari, Fabrizio
Singh, Alakshendra Jyotsnaditya Ramkrishna
Gebhard, Patrick
Computer Vision and Pattern Recognition
Artificial Intelligence
The goal of this investigation is to quantify to what extent computer vision methods can correctly classify facial expressions on a sign language dataset. We extend our experiments by recognizing expressions using only the upper or lower part of the face, which is needed to further investigate the difference in emotion manifestation between hearing and deaf subjects. To take into account the peculiar color profile of a dataset, our method introduces a color normalization stage based on histogram equalization and fine-tuning. The results show the ability to correctly recognize facial expressions with 83.8% mean sensitivity and very little variance (.042) among classes. Like for humans, recognition of expressions from the lower half of the face (79.6%) is higher than that from the upper half (77.9%). Noticeably, the classification accuracy from the upper half of the face is higher than human level.
title Color histogram equalization and fine-tuning to improve expression recognition of (partially occluded) faces on sign language datasets
topic Computer Vision and Pattern Recognition
Artificial Intelligence
url https://arxiv.org/abs/2507.20197