Deep Underwater Image Quality Assessment with Explicit Degradation Awareness Embedding

Underwater Image Quality Assessment (UIQA) is currently an area of intensive research interest. Existing deep learning-based UIQA models always learn a deep neural network to directly map the input degraded underwater image into a final quality score via end-to-end training. However, a wide variety of image contents or distortion types may correspond to the same quality score, making it challenging to train such a deep model merely with a single subjective quality score as supervision. An intuitive idea to solve this problem is to exploit more detailed degradation-aware information as supplementary guidance to facilitate model learning. In this paper, we devise a novel deep UIQA model with Explicit Degradation Awareness embedding, i.e., EDANet. To train the EDANet, a two-stage training strategy is adopted. First, a tailored Degradation Information Discovery subnetwork (DIDNet) is pre-trained to infer a residual map between the input degraded underwater image and its pseudoreference counterpart. The inferred residual map explicitly characterizes the local degradation of the input underwater image. The intermediate feature representations on the decoder side of DIDNet are then embedded into the Degradation-guided Quality Evaluation subnetwork (DQENet), which significantly enhances the feature characterization capability with higher degradation awareness for quality prediction. The superiority of our EDANet against 18 state-of-the-art methods has been well demonstrated by extensive comparisons on two benchmark datasets. The source code of our EDANet is available at https://github.com/yia-yuese/EDANet.