Meishvili, Givi (2022). Learning Representations for Controllable Image Restoration. (Thesis). Universität Bern, Bern

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Abstract

Deep Convolutional Neural Networks have sparked a renaissance in all the sub-fields of computer vision. Tremendous progress has been made in the area of image restoration. The research community has pushed the boundaries of image deblurring, super-resolution, and denoising. However, given a distorted image, most existing methods typically produce a single restored output. The tasks mentioned above are inherently ill-posed, leading to an infinite number of plausible solutions. This thesis focuses on designing image restoration techniques capable of producing multiple restored results and granting users more control over the restoration process. Towards this goal, we demonstrate how one could leverage the power of unsupervised representation learning. Image restoration is vital when applied to distorted images of human faces due to their social significance. Generative Adversarial Networks enable an unprecedented level of generated facial details combined with smooth latent space. We leverage the power of GANs towards the goal of learning controllable neural face representations. We demonstrate how to learn an inverse mapping from image space to these latent representations, tuning these representations towards a specific task, and finally manipulating latent codes in these spaces. For example, we show how GANs and their inverse mappings enable the restoration and editing of faces in the context of extreme face super-resolution and the generation of novel view sharp videos from a single motion-blurred image of a face. This thesis also addresses more general blind super-resolution, denoising, and scratch removal problems, where blur kernels and noise levels are unknown. We resort to contrastive representation learning and first learn the latent space of degradations. We demonstrate that the learned representation allows inference of ground-truth degradation parameters and can guide the restoration process. Moreover, it enables control over the amount of deblurring and denoising in the restoration via manipulation of latent degradation features.

Item Type:	Thesis
Granting Institution:	Faculty of Science, University of Bern
Dissertation Type:	Single
Date of Defense:	31 March 2022
Subjects:	000 Computer science, knowledge & systems 500 Science > 510 Mathematics
Institute / Center:	08 Faculty of Science 08 Faculty of Science > Institute of Computer Science (INF) > Computer Vision Group (CVG)
Depositing User:	Givi Meishvili
Date Deposited:	19 Aug 2022 14:45
Last Modified:	19 Aug 2022 14:50
URI:	https://boristheses.unibe.ch/id/eprint/3456

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