LPATR-Net: Learnable Piecewise Affine Transformation Regression Assisted Data-Driven Dehazing Framework

Nowadays, data-driven learning based deep neural network (DNN) is the most dominant SOTA image dehazing framework. Here, learning to perfectly simulate the underlying mapping rules (from hazy to clear) told by massive paired training data is its core driving force. However, under genuine scenarios, it is extremely hard to guarantee the 100% qualification of all collected ground truth (GT) haze-free data. That's because natural weather is hardly controlled, and many weathers are actually in a chaotic status existing between foggy and fog-free. Thus, unlike most supervised learning issues, the image dehazing society is born with the torture of part of faulty ground truth no-haze samples. Therefore, totally trusting training data and solely pursuing more fitting powerful data-driven model may not be a wise solution. To cope with this thorny challenge, in this paper, instead of faithfully pursuing for fitting capacity promotion, we on the contrary choose to intentionally cut down the fitting flexibility to achieve higher-level robustness. That is the LPATR-Net, a novel dehazing framework specially armed with fitting power suppression mechanism to resist intrinsic annoying faulty GT. This solution does not involve any extra manually labeling. Specifically, the LPATR-Net architecture is created completely around elaborately designed fitting-restrained learnable piecewise affine transformation regression. Since such low-order linear regression structure genetically can only fit for majority of data, the interference of minority of unqualified GT samples is expected to be effectively suppressed. Through further coupled with a highly customized multi-concerns high-accuracy dehazing fitting companion component, All-Mattering, proposed LPATR-Net elegantly achieves the seamless integration of traditional majority determining fixed-form regression and modern all freedom data-driven deep learning. Extensive experiments have been conducted on five commonly utilized public datasets to verify its effectiveness. In addition, the wide-range transplantability of the proposed core regression structure has also been experimentally confirmed. Source code is available at https://github.com/FeiChen829/LPATR-Net.