Normalization-Equivariant Neural Networks with Application to Image Denoising

Fuente: arXiv
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Autori principali: Herbreteau, Sébastien, Moebel, Emmanuel, Kervrann, Charles
Natura: Preprint
Pubblicazione: 2023
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author Herbreteau, Sébastien
Moebel, Emmanuel
Kervrann, Charles
author_facet Herbreteau, Sébastien
Moebel, Emmanuel
Kervrann, Charles
contents In many information processing systems, it may be desirable to ensure that any change of the input, whether by shifting or scaling, results in a corresponding change in the system response. While deep neural networks are gradually replacing all traditional automatic processing methods, they surprisingly do not guarantee such normalization-equivariance (scale + shift) property, which can be detrimental in many applications. To address this issue, we propose a methodology for adapting existing neural networks so that normalization-equivariance holds by design. Our main claim is that not only ordinary convolutional layers, but also all activation functions, including the ReLU (rectified linear unit), which are applied element-wise to the pre-activated neurons, should be completely removed from neural networks and replaced by better conditioned alternatives. To this end, we introduce affine-constrained convolutions and channel-wise sort pooling layers as surrogates and show that these two architectural modifications do preserve normalization-equivariance without loss of performance. Experimental results in image denoising show that normalization-equivariant neural networks, in addition to their better conditioning, also provide much better generalization across noise levels.
format Preprint
id arxiv_https___arxiv_org_abs_2306_05037
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Normalization-Equivariant Neural Networks with Application to Image Denoising
Herbreteau, Sébastien
Moebel, Emmanuel
Kervrann, Charles
Computer Vision and Pattern Recognition
In many information processing systems, it may be desirable to ensure that any change of the input, whether by shifting or scaling, results in a corresponding change in the system response. While deep neural networks are gradually replacing all traditional automatic processing methods, they surprisingly do not guarantee such normalization-equivariance (scale + shift) property, which can be detrimental in many applications. To address this issue, we propose a methodology for adapting existing neural networks so that normalization-equivariance holds by design. Our main claim is that not only ordinary convolutional layers, but also all activation functions, including the ReLU (rectified linear unit), which are applied element-wise to the pre-activated neurons, should be completely removed from neural networks and replaced by better conditioned alternatives. To this end, we introduce affine-constrained convolutions and channel-wise sort pooling layers as surrogates and show that these two architectural modifications do preserve normalization-equivariance without loss of performance. Experimental results in image denoising show that normalization-equivariant neural networks, in addition to their better conditioning, also provide much better generalization across noise levels.
title Normalization-Equivariant Neural Networks with Application to Image Denoising
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2306.05037