Faithful Extreme Image Rescaling with Learnable Reversible Transformation and Semantic Priors

Fuente: arXiv
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Main Authors: Wei, Hao, Zhou, Yanhui, Ge, Chenyang, Anwar, Saeed, Mian, Ajmal
Format: Preprint
Published: 2026
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author Wei, Hao
Zhou, Yanhui
Ge, Chenyang
Anwar, Saeed
Mian, Ajmal
author_facet Wei, Hao
Zhou, Yanhui
Ge, Chenyang
Anwar, Saeed
Mian, Ajmal
contents Most recent extreme rescaling methods struggle to preserve semantically consistent structures and produce realistic details, due to the severely ill-posed nature of low- to high-resolution mapping under scaling factors of $16\times$ or higher. To alleviate the above problems, we propose FaithEIR, a diffusion-based framework for extreme image rescaling. Inspired by singular value decomposition, we develop learnable reversible transformation that enables invertible downscaling and upscaling in the latent space. To compensate for information loss due to quantization, we propose an adaptive detail prior, a high-frequency dictionary that captures the empirical average of commonly occurring structures in the training data. Finally, we design a lightweight pixel semantic embedder to provide semantic conditioning for the pretrained diffusion model. We present extensive experimental results demonstrating that our FaithEIR consistently outperforms state-of-the-art methods, achieving superior reconstruction fidelity and perceptual quality. Our code, model weights, and detailed results are released at https://github.com/cshw2021/FaithEIR.
format Preprint
id arxiv_https___arxiv_org_abs_2605_00605
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Faithful Extreme Image Rescaling with Learnable Reversible Transformation and Semantic Priors
Wei, Hao
Zhou, Yanhui
Ge, Chenyang
Anwar, Saeed
Mian, Ajmal
Computer Vision and Pattern Recognition
Most recent extreme rescaling methods struggle to preserve semantically consistent structures and produce realistic details, due to the severely ill-posed nature of low- to high-resolution mapping under scaling factors of $16\times$ or higher. To alleviate the above problems, we propose FaithEIR, a diffusion-based framework for extreme image rescaling. Inspired by singular value decomposition, we develop learnable reversible transformation that enables invertible downscaling and upscaling in the latent space. To compensate for information loss due to quantization, we propose an adaptive detail prior, a high-frequency dictionary that captures the empirical average of commonly occurring structures in the training data. Finally, we design a lightweight pixel semantic embedder to provide semantic conditioning for the pretrained diffusion model. We present extensive experimental results demonstrating that our FaithEIR consistently outperforms state-of-the-art methods, achieving superior reconstruction fidelity and perceptual quality. Our code, model weights, and detailed results are released at https://github.com/cshw2021/FaithEIR.
title Faithful Extreme Image Rescaling with Learnable Reversible Transformation and Semantic Priors
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2605.00605