A new end-to-end image dehazing algorithm based on residual attention mechanism

基于残差注意力机制的图像去雾算法

School of Computer and Information Engineering, Tianjin Chengjian University, Tianjin 300384, China

Received: 17 December 2020

Abstract

Traditional image dehazing algorithms based on prior knowledge and deep learning rely on the atmospheric scattering model and are easy to cause color distortion and incomplete dehazing. To solve these problems, an end-to-end image dehazing algorithm based on residual attention mechanism is proposed in this paper. The network includes four modules: encoder, multi-scale feature extraction, feature fusion and decoder. The encoder module encodes the input haze image into feature map, which is convenient for subsequent feature extraction and reduces memory consumption; the multi-scale feature extraction module includes residual smoothed dilated convolution module, residual block and efficient channel attention, which can expand the receptive field and extract different scale features by filtering and weighting; the feature fusion module with efficient channel attention adjusts the channel weight dynamically, acquires rich context information and suppresses redundant information so as to enhance the ability to extract haze density image of the network; finally, the encoder module maps the fused feature nonlinearly to obtain the haze density image and then restores the haze free image. The qualitative and quantitative tests based on SOTS test set and natural haze images show good objective and subjective evaluation results. This algorithm improves the problems of color distortion and incomplete dehazing effectively.

摘要

传统基于先验知识与基于学习的图像去雾算法依赖大气散射模型，容易出现颜色失真和去雾不彻底的现象。针对上述问题，提出一种端到端的基于残差注意力机制的图像去雾算法，该算法网络包括编码、多尺度特征提取、特征融合和解码4个模块。编码模块将输入的雾图编码为特征图像，便于后续特征提取并减少内存占用；多尺度特征提取模块包括残差平滑空洞卷积模块、残差块和高效通道注意力机制，能够扩大感受野并通过加权筛选提取的不同尺度特征以便融合；特征融合模块利用高效通道注意力机制，动态调整不同尺度特征的通道权重，学习丰富的上下文信息并抑制冗余信息，增强网络提取雾霾密度图像的能力从而使去雾更加彻底；解码模块对融合后的特征进行非线性映射得到雾霾密度图像，进而恢复无雾图像。通过在SOTS测试集和自然有雾图像上进行定量和定性的测试，所提方法取得了较好的客观和主观评价结果，并有效改善了颜色失真和去雾不彻底的现象。