SEGAN:基于边缘信息指导的无监督图像增强

SEGAN: Unsupervised Image Enhancement Based on Edge Information Guidance

  • 摘要: 对低照度增强中配对图像缺乏、图像细节保留不足等问题,本文基于边缘信息指导的无监督(Generative Adversarial Network,GAN)网络进行低照度图像增强算法研究,该算法可以在没有低光/正常光图像对情况下进行无监督训练。在生成器部分,在U-Net架构中引入混合边缘信息的自正则化注意力图(Self-Regularized Attention Map,SAM)和HaLoAttention局部自注意力机制,结构引导的自特征指导增强模块(Structure-guided Self-feature Guided Enhancement,SSGE)引入注意力权重融合的边缘信息提取模块(Edge Extraction,EX)以及基于动态卷积和(Spatially-Adaptive Normalization,SPADE)归一化的边缘信息增强模块(Edge Information Enhancement,EIE)。然后,判别器部分采用全局-局部判别器结构,从生成器的增强结果和非配对正常光图像中随机裁剪,两者均使用PatchGAN进行真/假识别。实验结果表明:在由LOL-v2和LSRW组成的参考测试集上,本文算法在PSNR、SSIM和NIQE指标上优于对比方法(相比最佳对比方法提升0.79dB、0.02和0.2956)。此外,在DICM等无参考数据集上,本方法在NIQE指标上同样取得最优表现,增强结果更接近真实效果。

     

    Abstract: To address issues such as the lack of paired images and insufficient preservation of image details in low-light enhancement, this paper investigates a low-light image enhancement algorithm based on an unsupervised Generative Adversarial Network (GAN) guided by edge information. This algorithm enables unsupervised training even in the absence of low-light/normal-light image pairs. In the generator component, a Self-Regularized Attention Map (SAM) incorporating mixed edge information and the HaLoAttention local self-attention mechanism are introduced into the U-Net architecture. The Structure-guided Self-feature Guided Enhancement (SSGE) module incorporates an edge information extraction module (Edge Extraction, EX) that fuses attention weights and an edge information enhancement module (Edge Information Enhancement, EIE) based on dynamic convolution and Spatially-Adaptive Normalization (SPADE). The discriminator component adopts a global-local discriminator structure, randomly cropping from the generator's enhanced results and unpaired normal light images, both of which are subjected to true/false identification using PatchGAN. Experimental results show that on the reference test set composed of LOLv2 and LSRW, the proposed algorithm outperforms competing methods in PSNR, SSIM, and NIQE (with improvements of 0.8 dB, 0.02, and 0.3 over the best baseline). In addition, on the unreferenced datasets DICM, our method also achieves the best performance in NIQE, producing enhancement results that are closer to real-world effects.

     

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