Learning to zoom-in via learning to zoom-out: real-world super-resolution by generating and adapting degradation

dc.contributor.authorSun, W.
dc.contributor.authorGong, D.
dc.contributor.authorShi, Q.
dc.contributor.authorvan den Hengel, A.
dc.contributor.authorZhang, Y.
dc.date.issued2021
dc.description.abstractMost learning-based super-resolution (SR) methods aim to recover high-resolution (HR) image from a given low-resolution (LR) image via learning on LR-HR image pairs. The SR methods learned on synthetic data do not perform well in real-world, due to the domain gap between the artificially synthesized and real LR images. Some efforts are thus taken to capture real-world image pairs. However, the captured LR-HR image pairs usually suffer from unavoidable misalignment, which hampers the performance of end-to-end learning. Here, focusing on the real-world SR, we ask a different question: since misalignment is unavoidable, can we propose a method that does not need LR-HR image pairing and alignment at all and utilizes real images as they are? Hence we propose a framework to learn SR from an arbitrary set of unpaired LR and HR images and see how far a step can go in such a realistic and “unsupervised” setting. To do so, we firstly train a degradation generation network to generate realistic LR images and, more importantly, to capture their distribution (i.e., learning to zoom out). Instead of assuming the domain gap has been eliminated, we minimize the discrepancy between the generated data and real data while learning a degradation adaptive SR network (i.e., learning to zoom in). The proposed unpaired method achieves state-of-the-art SR results on real-world images, even in the datasets that favour the paired-learning methods more
dc.description.statementofresponsibilityWei Sun, Dong Gong, Qinfeng Shi, Anton van den Hengel and Yanning Zhang
dc.identifier.citationIEEE Transactions on Image Processing, 2021; 30:1-16
dc.identifier.doi10.1109/TIP.2021.3049951
dc.identifier.issn1057-7149
dc.identifier.issn1941-0042
dc.identifier.orcidShi, Q. [0000-0002-9126-2107]
dc.identifier.orcidvan den Hengel, A. [0000-0003-3027-8364]
dc.identifier.urihttp://hdl.handle.net/2440/130132
dc.language.isoen
dc.publisherInstitute of Electrical and Electronics Engineers
dc.rights© 2021 IEEE. Personal use is permitted, but republication/redistribution requires IEEE permission.
dc.source.urihttps://doi.org/10.1109/tip.2021.3049951
dc.subjectSuper resolution (SR); domain adaptation; unpaired learning
dc.titleLearning to zoom-in via learning to zoom-out: real-world super-resolution by generating and adapting degradation
dc.typeJournal article
pubs.publication-statusPublished

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