Papers › Blind Super-Resolution Kernel Estimation using an Internal-GAN

Blind Super-Resolution Kernel Estimation using an Internal-GAN

14 Sep 2019NeurIPS 2019 12arXiv:1909.06581archive 2025-07-28

Sefi Bell-Kligler, Assaf Shocher, Michal Irani

Super resolution (SR) methods typically assume that the low-resolution (LR) image was downscaled from the unknown high-resolution (HR) image by a fixed 'ideal' downscaling kernel (e.g. Bicubic downscaling). However, this is rarely the case in real LR images, in contrast to synthetically generated SR datasets. When the assumed downscaling kernel deviates from the true one, the performance of SR methods significantly deteriorates. This gave rise to Blind-SR - namely, SR when the downscaling kernel ("SR-kernel") is unknown. It was further shown that the true SR-kernel is the one that maximizes the recurrence of patches across scales of the LR image. In this paper we show how this powerful cross-scale recurrence property can be realized using Deep Internal Learning. We introduce "KernelGAN", an image-specific Internal-GAN, which trains solely on the LR test image at test time, and learns its internal distribution of patches. Its Generator is trained to produce a downscaled version of the LR test image, such that its Discriminator cannot distinguish between the patch distribution of the downscaled image, and the patch distribution of the original LR image. The Generator, once trained, constitutes the downscaling operation with the correct image-specific SR-kernel. KernelGAN is fully unsupervised, requires no training data other than the input image itself, and leads to state-of-the-art results in Blind-SR when plugged into existing SR algorithms.

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sefibk/KernelGAN officialmentioned on GitHubpytorchNOASSERTION report
BillOuyang/KernelGan-s3 mentioned on GitHubpytorch report
Lornatang/KernelGAN mentioned on GitHubpytorchApache-2.0 report
RomanovIgnat/KernelGAN mentioned on GitHubpytorchNOASSERTION report

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1ran · our draft was wrong
2ran · fixture could not drive it
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contributions Lornatang/KernelGAN/imresize.py community (archive-listed) ran Apache-2.0 (permissive) · b921438690ac017f · report
downscale BillOuyang/KernelGan-s3/datagenerator/generator.py community (archive-listed) ran · fixture could not drive it licence not identified · pointer only · 2c3537174371eb3d · report
fix_scale_and_size Lornatang/KernelGAN/imresize.py community (archive-listed) ran Apache-2.0 (permissive) · ee75635bb6c497f1 · report
gen_kernel BillOuyang/KernelGan-s3/datagenerator/generator.py community (archive-listed) ran · our draft was wrong licence not identified · pointer only · 2b6d632ae7409fb5 · report
kernel_shift BillOuyang/KernelGan-s3/datagenerator/generator.py community (archive-listed) ran · fixture could not drive it fingerprinted licence not identified · pointer only · 247be28fb1025380 · report
im2tensor Lornatang/KernelGAN/util.py community (archive-listed) unverified Apache-2.0 (permissive) · 9cb8c14a5a5d6d3b · report
imresize Lornatang/KernelGAN/imresize.py community (archive-listed) unverified Apache-2.0 (permissive) · 7b064b7f22f1a281 · report
kernel_shift Lornatang/KernelGAN/ZSSRforKernelGAN/zssr_utils.py community (archive-listed) unverified Apache-2.0 (permissive) · aebde4515b49a7ab · report
move2cpu Lornatang/KernelGAN/util.py community (archive-listed) unverified Apache-2.0 (permissive) · ae7a590467df97d5 · report
preprocess_kernels Lornatang/KernelGAN/ZSSRforKernelGAN/zssr_utils.py community (archive-listed) unverified Apache-2.0 (permissive) · ce5184edff18c76c · report
random_augment Lornatang/KernelGAN/ZSSRforKernelGAN/zssr_utils.py community (archive-listed) unverified Apache-2.0 (permissive) · 1b0a3179c34cf2e7 · report
tensor2im Lornatang/KernelGAN/util.py community (archive-listed) unverified Apache-2.0 (permissive) · 7a4d057c155883e4 · report

Tasks

Blind Super-ResolutionSuper-Resolution

Datasets

Introduced by this paper, per the archive.

DIV2KRK

Results from the paper archive 2025-07-28

TaskDatasetModelMetricValueRank at snapshotLeaderboardReport
Blind Super-Resolution DIV2KRK - 2x upscaling KernelGAN+ZSSR PSNR 30.36 #5 of 5 Archive leaderboard report
Blind Super-Resolution DIV2KRK - 2x upscaling KernelGAN+ZSSR SSIM 0.8669 #5 of 5 Archive leaderboard report

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