ProtoTTA: Prototype-Guided Test-Time Adaptation

Fuente: arXiv
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Main Authors: Abootorabi, Mohammad Mahdi, Mousavi, Parvin, Abolmaesumi, Purang, Shelhamer, Evan
Format: Preprint
Published: 2026
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author Abootorabi, Mohammad Mahdi
Mousavi, Parvin
Abolmaesumi, Purang
Shelhamer, Evan
author_facet Abootorabi, Mohammad Mahdi
Mousavi, Parvin
Abolmaesumi, Purang
Shelhamer, Evan
contents Deep networks that rely on prototypes-interpretable representations that can be related to the model input-have gained significant attention for balancing high accuracy with inherent interpretability, which makes them suitable for critical domains such as healthcare. However, these models are limited by their reliance on training data, which hampers their robustness to distribution shifts. While test-time adaptation (TTA) improves the robustness of deep networks by updating parameters and statistics, the prototypes of interpretable models have not been explored for this purpose. We introduce ProtoTTA, a general framework for prototypical models that leverages intermediate prototype signals rather than relying solely on model outputs. ProtoTTA minimizes the entropy of the prototype-similarity distribution to encourage more confident and prototype-specific activations on shifted data. To maintain stability, we employ geometric filtering to restrict updates to samples with reliable prototype activations, regularized by prototype-importance weights and model-confidence scores. Experiments across four prototypical backbones on four diverse benchmarks spanning fine-grained vision, histopathology, and NLP demonstrate that ProtoTTA improves robustness over standard output entropy minimization while restoring correct semantic focus in prototype activations. We also introduce novel interpretability metrics and a vision-language model (VLM) evaluation framework to explain TTA dynamics, confirming ProtoTTA restores human-aligned semantic focus and correlates reliably with VLM-rated reasoning quality. Code is available at: https://github.com/DeepRCL/ProtoTTA.
format Preprint
id arxiv_https___arxiv_org_abs_2604_15494
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle ProtoTTA: Prototype-Guided Test-Time Adaptation
Abootorabi, Mohammad Mahdi
Mousavi, Parvin
Abolmaesumi, Purang
Shelhamer, Evan
Machine Learning
Computer Vision and Pattern Recognition
Deep networks that rely on prototypes-interpretable representations that can be related to the model input-have gained significant attention for balancing high accuracy with inherent interpretability, which makes them suitable for critical domains such as healthcare. However, these models are limited by their reliance on training data, which hampers their robustness to distribution shifts. While test-time adaptation (TTA) improves the robustness of deep networks by updating parameters and statistics, the prototypes of interpretable models have not been explored for this purpose. We introduce ProtoTTA, a general framework for prototypical models that leverages intermediate prototype signals rather than relying solely on model outputs. ProtoTTA minimizes the entropy of the prototype-similarity distribution to encourage more confident and prototype-specific activations on shifted data. To maintain stability, we employ geometric filtering to restrict updates to samples with reliable prototype activations, regularized by prototype-importance weights and model-confidence scores. Experiments across four prototypical backbones on four diverse benchmarks spanning fine-grained vision, histopathology, and NLP demonstrate that ProtoTTA improves robustness over standard output entropy minimization while restoring correct semantic focus in prototype activations. We also introduce novel interpretability metrics and a vision-language model (VLM) evaluation framework to explain TTA dynamics, confirming ProtoTTA restores human-aligned semantic focus and correlates reliably with VLM-rated reasoning quality. Code is available at: https://github.com/DeepRCL/ProtoTTA.
title ProtoTTA: Prototype-Guided Test-Time Adaptation
topic Machine Learning
Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2604.15494