Ji Lu, Chen Chao
College of Aeronautics, Nanjing University of Aeronautics and Astronautics, Nanjing 210006, China.
Sensors (Basel). 2025 Aug 15;25(16):5088. doi: 10.3390/s25165088.
The aim of this study was to address the issue of significant performance degradation in existing defogging algorithms under extreme fog conditions. Traditional Taylor series-based deformable convolutions are limited by local approximation errors, while the heavy-tailed characteristics of the Cauchy distribution can more successfully model outliers in fog images. The following improvements are made: (1) A displacement generator based on the inverse cumulative distribution function (ICDF) of the Cauchy distribution is designed to transform uniform noise into sampling points with a long-tailed distribution. A novel double-peak Cauchy ICDF is proposed to dynamically balance the heavy-tailed characteristics of the Cauchy ICDF, enhancing the modeling capability for sudden changes in fog concentration. (2) An innovative Cauchy-Gaussian fusion module is proposed to dynamically learn and generate hybrid coefficients, combining the complementary advantages of the two distributions to dynamically balance the representation of smooth regions and edge details. (3) Tree-based multi-path and cross-resolution feature aggregation is introduced, achieving local-global feature adaptive fusion through adjustable window sizes (3/5/7/11) for parallel paths. Experiments on the RESIDE dataset demonstrate that the proposed method achieves a 2.26 dB improvement in the peak signal-to-noise ratio compared to that obtained with the TaylorV2 expansion attention mechanism, with an improvement of 0.88 dB in heavily hazy regions (fog concentration > 0.8). Ablation studies validate the effectiveness of Cauchy distribution convolution in handling dense fog and conventional lighting conditions. This study provides a new theoretical perspective for modeling in computer vision tasks, introducing a novel attention mechanism and multi-path encoding approach.
本研究的目的是解决现有去雾算法在极端雾天条件下性能显著下降的问题。传统的基于泰勒级数的可变形卷积受局部近似误差的限制,而柯西分布的重尾特性能够更成功地对雾图像中的异常值进行建模。为此进行了以下改进:(1)设计了一种基于柯西分布逆累积分布函数(ICDF)的位移生成器,将均匀噪声转换为具有长尾分布的采样点。提出了一种新颖的双峰柯西ICDF,以动态平衡柯西ICDF的重尾特性,增强对雾浓度突然变化的建模能力。(2)提出了一种创新的柯西 - 高斯融合模块,用于动态学习和生成混合系数,结合两种分布的互补优势,动态平衡平滑区域和边缘细节的表示。(3)引入基于树的多路径和跨分辨率特征聚合,通过为并行路径设置可调窗口大小(3/5/7/11)实现局部 - 全局特征自适应融合。在RESIDE数据集上的实验表明,与使用泰勒V2扩展注意力机制相比,该方法的峰值信噪比提高了2.26 dB,在浓雾区域(雾浓度>0.8)提高了0.88 dB。消融研究验证了柯西分布卷积在处理浓雾和传统光照条件下的有效性。本研究为计算机视觉任务中的建模提供了新的理论视角,引入了一种新颖的注意力机制和多路径编码方法。