Revelio: A Real-World Screen-Camera Communication System with Visually Imperceptible Data Embedding

2025-01-04

AI Summary

To address the trade-off between visual imperceptibility and decoding robustness in screen-to-camera covert communication, this paper proposes a temporal flicker fusion mechanism based on the OKLAB color space, enabling fully imperceptible data embedding to the human eye. We innovatively design a pixel-region shape coding scheme coupled with a spatially adaptive flicker modulation strategy to enhance embedding capacity and interference resilience. Furthermore, we introduce a two-stage CNN-based decoder and a weighted differential accumulation frame detector, significantly improving robustness against asynchronous sampling, motion blur, illumination variation, and display refresh rate mismatch. Evaluated in interactive television scenarios, the system supports real-time decoding on off-the-shelf smartphones, achieves zero visual artifacts, and outperforms state-of-the-art methods in both end-to-end communication throughput and stability.

Technology Category

• Computer Vision: Multi-modal Vision
• Cognitive Modeling & Cognitive Systems: Neural Spike Coding
• Machine Learning: Privacy

Application Category

• Security and Privacy: Large-scale security measurements
• Responsible Web: Measurement, analysis, and circumvention of Web censorship
• User Modeling, Personalization and Recommendation: User privacy protection in personalized systems

Abstract

We present `Revelio', a real-world screen-camera communication system leveraging temporal flicker fusion in the OKLAB color space. Using spatially-adaptive flickering and encoding information in pixel region shapes, Revelio achieves visually imperceptible data embedding while remaining robust against noise, asynchronicity, and distortions in screen-camera channels, ensuring reliable decoding by standard smartphone cameras. The decoder, driven by a two-stage neural network, uses a weighted differential accumulator for precise frame detection and symbol recognition. Initial experiments demonstrate Revelio's effectiveness in interactive television, offering an unobtrusive method for meta-information transmission.

Problem

• Stealth Communication
• Screen-Camera Link
• User Experience Preservation

Innovation

• OKLAB color space
• invisible screen flickering
• dual-step decoding algorithm