The seminal work of Gatys et al. demonstrated the power of Convolutional Neural Networks (CNNs) in creating artistic imagery by separating and recombining image content and style. This process of using CNNs to render a content image in different styles is referred to as Neural Style Transfer (NST). Since then, NST has become a trending topic both in academic literature and industrial applications. It is receiving increasing attention and a variety of approaches are proposed to either improve or extend the original NST algorithm. In this paper, we aim to provide a comprehensive overview of the current progress towards NST. We first propose a taxonomy of current algorithms in the field of NST. Then, we present several evaluation methods and compare different NST algorithms both qualitatively and quantitatively. The review concludes with a discussion of various applications of NST and open problems for future research. A list of papers discussed in this review, corresponding codes, pre-trained models and more comparison results are publicly available at: https://github.com/ycjing/Neural-Style-Transfer-Papers. IndexTerms-Neural style transfer (NST), convolutional neural network ! Neural Style Transfer Example-Based Techniques Colour Image Analogy Texture Model-Optimisation-Based Offline Neural Methods Multiple-Style-Per-Model Neural Methods Dumoulin'17 [53] Chen'17 [54] Li'17 [55] Zhang'17 [56] Luan'17 [84] Mechrez'17 [85]Photorealistic Liao'17 [88] Attribute Champandard'16 [65] Doodle Ruder'16 [74] Video Selim'16 [73] Portrait Castillo'17 [71] Instance Gatys'17 [60] Improvement Image Gatys'16 [10] Li'17 [42] Risser'17 [44] Li'17 [45] Li'16 [46] Image Champandard'16 [65] Chen'16 [68] Mechrez'18 [69]

The Fast Style Transfer methods have been recently proposed to transfer a photograph to an artistic style in real-time. This task involves controlling the stroke size in the stylized results, which remains an open challenge. In this paper, we present a stroke controllable style transfer network that can achieve continuous and spatial stroke size control. By analyzing the factors that influence the stroke size, we propose to explicitly account for the receptive field and the style image scales. We propose a StrokePyramid module to endow the network with adaptive receptive fields, and two training strategies to achieve faster convergence and augment new stroke sizes upon a trained model respectively. By combining the proposed runtime control strategies, our network can achieve continuous changes in stroke sizes and produce distinct stroke sizes in different spatial regions within the same output image.

Chemical reaction prediction, involving forward synthesis and retrosynthesis prediction, is a fundamental problem in organic synthesis. A popular computational paradigm formulates synthesis prediction as a sequence-to-sequence translation problem, where the...

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