Hybrid Water-Filling: Simultaneous Shadow and Reflection Removal with adaptive luminance mask
概要
Digitizing documents such as business cards with mobile devices often results in degraded images due to shadows and specular reflections caused by uncontrolled illumination and varied capturing angles. Such artifacts significantly reduce visual quality and compromise the accuracy of downstream applications such as Optical character recognition (OCR). Although existing illumination-aware shadow removal approaches mitigate shadows in textual documents, they often suppress low-luminance non-textual elements such as logos and portraits, and, more critically, fail to handle shadows and reflections simultaneously. To address these challenges, we propose the Hybrid-Water-Filling method, an enhanced variant of the Water-Filling algorithm incorporating an inverted reflection-suppression step and an adaptive luminance masking strategy. Experimental results demonstrate that Hybrid-Water-Filling significantly enhances the visual quality without compromising shadow removal effectiveness.