  Removing multiple degradations, such as haze, rain, and blur, from real-world
images poses a challenging and illposed problem. Recently, unified models that
can handle different degradations have been proposed and yield promising
results. However, these approaches focus on synthetic images and experience a
significant performance drop when applied to realworld images. In this paper,
we introduce Uni-Removal, a twostage semi-supervised framework for addressing
the removal of multiple degradations in real-world images using a unified model
and parameters. In the knowledge transfer stage, Uni-Removal leverages a
supervised multi-teacher and student architecture in the knowledge transfer
stage to facilitate learning from pretrained teacher networks specialized in
different degradation types. A multi-grained contrastive loss is introduced to
enhance learning from feature and image spaces. In the domain adaptation stage,
unsupervised fine-tuning is performed by incorporating an adversarial
discriminator on real-world images. The integration of an extended
multi-grained contrastive loss and generative adversarial loss enables the
adaptation of the student network from synthetic to real-world domains.
Extensive experiments on real-world degraded datasets demonstrate the
effectiveness of our proposed method. We compare our Uni-Removal framework with
state-of-the-art supervised and unsupervised methods, showcasing its promising
results in real-world image dehazing, deraining, and deblurring simultaneously.
