  Single image dehazing is a challenging ill-posed problem due to the severe
information degeneration. However, existing deep learning based dehazing
methods only adopt clear images as positive samples to guide the training of
dehazing network while negative information is unexploited. Moreover, most of
them focus on strengthening the dehazing network with an increase of depth and
width, leading to a significant requirement of computation and memory. In this
paper, we propose a novel contrastive regularization (CR) built upon
contrastive learning to exploit both the information of hazy images and clear
images as negative and positive samples, respectively. CR ensures that the
restored image is pulled to closer to the clear image and pushed to far away
from the hazy image in the representation space. Furthermore, considering
trade-off between performance and memory storage, we develop a compact dehazing
network based on autoencoder-like (AE) framework. It involves an adaptive mixup
operation and a dynamic feature enhancement module, which can benefit from
preserving information flow adaptively and expanding the receptive field to
improve the network's transformation capability, respectively. We term our
dehazing network with autoencoder and contrastive regularization as AECR-Net.
The extensive experiments on synthetic and real-world datasets demonstrate that
our AECR-Net surpass the state-of-the-art approaches. The code is released in
https://github.com/GlassyWu/AECR-Net.
