Learning to Align Generative Appearance Priors for Fine-grained Image Retrieval

Fuente: arXiv
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Main Authors: Wang, Shijie, Luo, Yadan, Wang, Zijian, Yu, Xin, Huang, Zi
Format: Preprint
Published: 2026
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author Wang, Shijie
Luo, Yadan
Wang, Zijian
Yu, Xin
Huang, Zi
author_facet Wang, Shijie
Luo, Yadan
Wang, Zijian
Yu, Xin
Huang, Zi
contents Fine-grained image retrieval (FGIR) typically relies on supervision from seen categories to learn discriminative embeddings for retrieving unseen categories. However, such supervision often biases retrieval models toward the semantics of seen categories rather than the underlying appearance characteristics that generalize across categories, thereby limiting retrieval performance on unseen categories. To tackle this, we propose GAPan, a Generative Appearance Prior alignment network that reformulates the learning objective from category prediction toward appearance modeling. Technically, GAPan treats retrieval features with an invertible density model based on normalizing flows. In the forward direction, the flow maps all instance features into a latent density space, where each seen category is modeled by a class-conditional Gaussian prior and optimized via exact likelihood estimation. This formulation preserves richer appearance details by leveraging the invertible property of the flows. In the reverse direction, samples from the high-density regions of these learned priors are mapped back to the feature space to produce appearance-aware anchors that reflect intra-category variation. These anchors supervise a prior-driven alignment objective that aligns retrieval embeddings with category-specific appearance distributions, thereby improving generalization to unseen categories. Evaluations demonstrate that our GAPan achieves state-of-the-art performance on both widely-used fine- and coarse-grained benchmarks.
format Preprint
id arxiv_https___arxiv_org_abs_2605_09859
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Learning to Align Generative Appearance Priors for Fine-grained Image Retrieval
Wang, Shijie
Luo, Yadan
Wang, Zijian
Yu, Xin
Huang, Zi
Computer Vision and Pattern Recognition
Fine-grained image retrieval (FGIR) typically relies on supervision from seen categories to learn discriminative embeddings for retrieving unseen categories. However, such supervision often biases retrieval models toward the semantics of seen categories rather than the underlying appearance characteristics that generalize across categories, thereby limiting retrieval performance on unseen categories. To tackle this, we propose GAPan, a Generative Appearance Prior alignment network that reformulates the learning objective from category prediction toward appearance modeling. Technically, GAPan treats retrieval features with an invertible density model based on normalizing flows. In the forward direction, the flow maps all instance features into a latent density space, where each seen category is modeled by a class-conditional Gaussian prior and optimized via exact likelihood estimation. This formulation preserves richer appearance details by leveraging the invertible property of the flows. In the reverse direction, samples from the high-density regions of these learned priors are mapped back to the feature space to produce appearance-aware anchors that reflect intra-category variation. These anchors supervise a prior-driven alignment objective that aligns retrieval embeddings with category-specific appearance distributions, thereby improving generalization to unseen categories. Evaluations demonstrate that our GAPan achieves state-of-the-art performance on both widely-used fine- and coarse-grained benchmarks.
title Learning to Align Generative Appearance Priors for Fine-grained Image Retrieval
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2605.09859