SeD: Semantic-Aware Discriminator for Image Super-Resolution
This work addresses texture quality issues in image super-resolution for applications like photography and computer vision, representing an incremental improvement over existing GAN methods.
The paper tackles the problem of coarse-grained distribution learning in GAN-based image super-resolution, which causes virtual textures and counter-intuitive results, by proposing a Semantic-aware Discriminator (SeD) that uses semantic conditions from pretrained vision models to guide fine-grained texture generation, achieving more photo-realistic images as demonstrated in experiments on SR and Real SR tasks.
Generative Adversarial Networks (GANs) have been widely used to recover vivid textures in image super-resolution (SR) tasks. In particular, one discriminator is utilized to enable the SR network to learn the distribution of real-world high-quality images in an adversarial training manner. However, the distribution learning is overly coarse-grained, which is susceptible to virtual textures and causes counter-intuitive generation results. To mitigate this, we propose the simple and effective Semantic-aware Discriminator (denoted as SeD), which encourages the SR network to learn the fine-grained distributions by introducing the semantics of images as a condition. Concretely, we aim to excavate the semantics of images from a well-trained semantic extractor. Under different semantics, the discriminator is able to distinguish the real-fake images individually and adaptively, which guides the SR network to learn the more fine-grained semantic-aware textures. To obtain accurate and abundant semantics, we take full advantage of recently popular pretrained vision models (PVMs) with extensive datasets, and then incorporate its semantic features into the discriminator through a well-designed spatial cross-attention module. In this way, our proposed semantic-aware discriminator empowered the SR network to produce more photo-realistic and pleasing images. Extensive experiments on two typical tasks, i.e., SR and Real SR have demonstrated the effectiveness of our proposed methods.