Publication Type

Journal Article

Version

publishedVersion

Publication Date

2-2020

Abstract

We propose a novel deep example-based image colourization method called dense encoding pyramid network. In our study, we define the colourization as a multinomial classification problem. Given a greyscale image and a reference image, the proposed network leverages large-scale data and then predicts colours by analysing the colour distribution of the reference image. We design the network as a pyramid structure in order to exploit the inherent multi-scale, pyramidal hierarchy of colour representations. Between two adjacent levels, we propose a hierarchical decoder–encoder filter to pass the colour distributions from the lower level to higher level in order to take both semantic information and fine details into account during the colourization process. Within the network, a novel parallel residual dense block is proposed to effectively extract the local–global context of the colour representations by widening the network. Several experiments, as well as a user study, are conducted to evaluate the performance of our network against state-of-the-art colourization methods. Experimental results show that our network is able to generate colourful, semantically correct and visually pleasant colour images. In addition, unlike fully automatic colourization that produces fixed colour images, the reference image of our network is flexible; both natural images and simple colour palettes can be used to guide the colourization. © 2019 The Authors Computer Graphics Forum

Keywords

Computational photography, Computing methodologies, Computing methodology, neural network, Example based, I.3.3 [computer graphics], I.3.3 [computer graphic], picture/image, Image and video processing, Images processing, Neural-networks, Reference image

Discipline

Graphics and Human Computer Interfaces

Research Areas

Information Systems and Management

Publication

Computer Graphics Forum

Volume

39

Issue

1

First Page

20

Last Page

33

ISSN

0167-7055

Identifier

10.1111/cgf.13659

Publisher

Wiley

Additional URL

https://doi.org/10.1111/cgf.13659

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