I. Introduction
In recent years, artificial intelligence can process more complex computer vision tasks with the development of deep learning. Recently, scholars have started to use artificial intelligence to create art. By letting neural networks learn from past artworks, it was found that computers can analyze artworks and create new ones [1]. Regarding artistic creation, a recent popular technique is image style transfer. This technique extracts features from one or more images designated as reference styles and performs stylization on input images defined as content images whose structure remains unchanged. The style transfer neuron network outputs an image that combines the content of the input image and the styles of one or more reference images [2]. With this technique, the styles of world-famous artists can be transferred to any existing image.