基于阴影浓度提取与引导的文档图像阴影去除算法
Shadow Density Extraction and Guidancebased Document Image Shadow RemovalAlgorithm
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摘要: 针对已有文档图像阴影去除方法没有考虑软阴影特征导致的阴影边缘残留和偏色等问题, 提出一种基于阴影浓度提取与引导的文档图像阴影去除算法. 首先在文档图像去阴影数据集中设计阴影浓度计算模型, 生成准确的阴影浓度图, 用于单独训练阴影浓度提取网络; 然后冻结阴影浓度提取网络, 通过设计阴影浓度融合模块融合阴影浓度特征和文档阴影图像特征, 并引导文档阴影去除网络的单独训练过程, 得到初始的阴影去除效果; 最后联合训练阴影浓度提取网络和文档阴影去除网络, 通过参数微调优化实现更佳的阴影去除效果. 实验结果表明, 在RDD数据集上, 与主流方法相比, 所提算法的SSIM, PSNR提升0.73%和6.25%, RMSE降低21.00%; 在SD7K数据集上, 该算法的SSIM, PSNR提升0.16%和11.35%, RMSE降低36.22%.Abstract: Existing document image shadow removal methods neglect soft shadow characteristics, causing residual shadow edges and color distortion. A novel algorithm is proposed based on shadow density extraction and guidance. First, precise shadow density maps are generated in the document image shadow removal dataset through a designed shadow density calculation model to independently train shadow density extraction network (SDENet). Subsequently, with SDENet frozen, shadow density fusion module (SDFM) fuses shad-ow density features and document shadow image features to guide the separate training process of the document shadow removal network (DSRNet) for initial shadow removal. Finally, joint training of SDENet and DSRNet with parameter fine-tuning achieves improved performance. Experimental results demonstrate that compared to state-of-the-art methods, the proposed algorithm improves SSIM and PSNR by 0.73% and 6.25% respectively while reducing RMSE by 21.00% on the RDD dataset, and improves SSIM and PSNR by 0.16% and 11.35% respectively while reducing RMSE by 36.22% on the SD7K dataset.