Hierarchical Adaptive Filtering Network for Text Image Specular Highlight Removal

Abstract

Despite significant advances in the field of specular highlight removal in recent years, existing methods predominantly focus on natural images, where highlights typically appear on raised or edged surfaces of objects. These highlights are often small and sparsely distributed. However, for text images such as cards and posters, the flat surfaces reflect light uniformly, resulting in large areas of highlights. Current methods struggle with these large-area highlights in text images, often producing severe visual artifacts or noticeable discrepancies between filled pixels and the original image in the central high-intensity highlight areas. To address these challenges, we propose the Hierarchical Adaptive Filtering Network (HAFNet). Our approach performs filtering at both the downsampled deep feature layer and the upsampled image reconstruction layer. By designing and applying the Adaptive Comprehensive Filtering Module (ACFM) and Adaptive Dilated Filtering Module (ADFM) at different layers, our method effectively restores semantic information in large-area specular highlight regions and recovers detail loss at various scales. The required filtering kernels are pre-generated by a prediction network, allowing them to adaptively adjust according to different images and their semantic content, enabling robust performance across diverse scenarios. Additionally, we utilize Unity3D to construct a comprehensive large-area highlight dataset featuring images with rich texts and complex textures. Experimental results on various datasets demonstrate that our method outperforms state-of-the-art approaches.