Robust Watermarking Against Camera Shooting for PowerPoint Presentation

With the proliferation of smartphones, preserving the confidentiality of digital documents has become increasingly challenging. Document formats, such as PowerPoint (PPT), are particularly susceptible to unauthorized capture and leakage through smartphone cameras. In this letter, we propose a camera shooting resilient watermarking for PowerPoint presentation based on the PPT master layout backdrop, which exhibits two key properties. 1) Imperceptibility. We employ a difference-based embedding method on the PPT master layout backdrop to ensure good visual quality of the watermarked PPT. 2) Robustness. We design a distance-based selection method for embedding coefficients, ensuring the watermark's robustness under various shooting conditions. The experimental results demonstrate the robustness of our scheme against screen and projection shooting of PPT presentation, across diverse shooting distances, angles, and coverage levels of the PPT master layout backdrop.