ViTNT-FIQA: Training-Free Face Image Quality Assessment with Vision Transformers

Fuente: arXiv
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Autori principali: Ozgur, Guray, Caldeira, Eduarda, Chettaoui, Tahar, Kolf, Jan Niklas, Huber, Marco, Damer, Naser, Boutros, Fadi
Natura: Preprint
Pubblicazione: 2026
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author Ozgur, Guray
Caldeira, Eduarda
Chettaoui, Tahar
Kolf, Jan Niklas
Huber, Marco
Damer, Naser
Boutros, Fadi
author_facet Ozgur, Guray
Caldeira, Eduarda
Chettaoui, Tahar
Kolf, Jan Niklas
Huber, Marco
Damer, Naser
Boutros, Fadi
contents Face Image Quality Assessment (FIQA) is essential for reliable face recognition systems. Current approaches primarily exploit only final-layer representations, while training-free methods require multiple forward passes or backpropagation. We propose ViTNT-FIQA, a training-free approach that measures the stability of patch embedding evolution across intermediate Vision Transformer (ViT) blocks. We demonstrate that high-quality face images exhibit stable feature refinement trajectories across blocks, while degraded images show erratic transformations. Our method computes Euclidean distances between L2-normalized patch embeddings from consecutive transformer blocks and aggregates them into image-level quality scores. We empirically validate this correlation on a quality-labeled synthetic dataset with controlled degradation levels. Unlike existing training-free approaches, ViTNT-FIQA requires only a single forward pass without backpropagation or architectural modifications. Through extensive evaluation on eight benchmarks (LFW, AgeDB-30, CFP-FP, CALFW, Adience, CPLFW, XQLFW, IJB-C), we show that ViTNT-FIQA achieves competitive performance with state-of-the-art methods while maintaining computational efficiency and immediate applicability to any pre-trained ViT-based face recognition model.
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institution arXiv
publishDate 2026
record_format arxiv
spellingShingle ViTNT-FIQA: Training-Free Face Image Quality Assessment with Vision Transformers
Ozgur, Guray
Caldeira, Eduarda
Chettaoui, Tahar
Kolf, Jan Niklas
Huber, Marco
Damer, Naser
Boutros, Fadi
Computer Vision and Pattern Recognition
Machine Learning
Face Image Quality Assessment (FIQA) is essential for reliable face recognition systems. Current approaches primarily exploit only final-layer representations, while training-free methods require multiple forward passes or backpropagation. We propose ViTNT-FIQA, a training-free approach that measures the stability of patch embedding evolution across intermediate Vision Transformer (ViT) blocks. We demonstrate that high-quality face images exhibit stable feature refinement trajectories across blocks, while degraded images show erratic transformations. Our method computes Euclidean distances between L2-normalized patch embeddings from consecutive transformer blocks and aggregates them into image-level quality scores. We empirically validate this correlation on a quality-labeled synthetic dataset with controlled degradation levels. Unlike existing training-free approaches, ViTNT-FIQA requires only a single forward pass without backpropagation or architectural modifications. Through extensive evaluation on eight benchmarks (LFW, AgeDB-30, CFP-FP, CALFW, Adience, CPLFW, XQLFW, IJB-C), we show that ViTNT-FIQA achieves competitive performance with state-of-the-art methods while maintaining computational efficiency and immediate applicability to any pre-trained ViT-based face recognition model.
title ViTNT-FIQA: Training-Free Face Image Quality Assessment with Vision Transformers
topic Computer Vision and Pattern Recognition
Machine Learning
url https://arxiv.org/abs/2601.05741