Recently, several models based on deep neural networks have achieved great success in terms of both reconstruction accuracy and computational performance for single image super-resolution. In these methods, the low resolution (LR) input image is upscaled to the high resolution (HR) space using a single filter, commonly bicubic interpolation, before reconstruction. This means that the super-resolution (SR) operation is performed in HR space. We demonstrate that this is sub-optimal and adds computational complexity. In this paper, we present the first convolutional neural network (CNN) capable of real-time SR of 1080p videos on a single K2 GPU. To achieve this, we propose a novel CNN architecture where the feature maps are extracted in the LR space. In addition, we introduce an efficient sub-pixel convolution layer which learns an array of upscaling filters to upscale the final LR feature maps into the HR output. By doing so, we effectively replace the handcrafted bicubic filter in the SR pipeline with more complex upscaling filters specifically trained for each feature map, whilst also reducing the computational complexity of the overall SR operation. We evaluate the proposed approach using images and videos from publicly available datasets and show that it performs significantly better (+0.15dB on Images and +0.39dB on Videos) and is an order of magnitude faster than previous CNN-based methods.

本文提出一种卷积神经网络，该网络的特征图在低分辨率空间中提取，使用高效的子像素卷积层将最终的低分辨率特征图升级到高分辨率输出，从而有效地将手工设计的双三次滤波器替换为针对每个特征图训练的更复杂的上采样滤波器，同时降低总体超分辨率操作的计算复杂度。该方法的实验结果表明，它在图像和视频方面的表现都比以前的基于CNN的方法好得多，并且速度快了一个数量级。

使用高效子像素卷积神经网络的实时单图像和视频超分辨率