ChromaCode: A Fully Imperceptible Screen-Camera Communication System

Authors:
Kai Zhang School of Software and TNList, Tsinghua University
Chenshu Wu University of Maryland, College Park
Chaofan Yang School of Software and TNList, Tsinghua University
Yi Zhao School of Software and TNList, Tsinghua University
Kehong Huang School of Software and TNList, Tsinghua University
Chunyi Peng Department of Computer Science, Purdue University
Yunhao Liu School of Software and TNList, Tsinghua University
Zheng Yang School of Software and TNList, Tsinghua University

Introduction:

this paper studies Hidden screen-camera communication techniques . In this paper, the authors present the design and implementation of ChromaCode, a screen-camera communication system that achieves all three goals simultaneously.

Abstract:

Hidden screen-camera communication techniques emerge as a new paradigm that embeds data imperceptibly into regular videos while remaining unobtrusive to human viewers. Three key goals on imperceptible, high rate, and reliable communication are desirable but conflicting, and existing solutions usually made a trade-of among them. In this paper, we present the design and implementation of ChromaCode, a screen-camera communication system that achieves all three goals simultaneously. In our design, we consider for the first time color space for perceptually uniform lightness modifications. On this basis, we design an outcome-based adaptive embedding scheme, which adapts to both pixel lightness and regional texture. Last, we propose a concatenated code scheme for robust coding and devise multiple techniques to overcome various screen-camera channel errors. Our prototype and experiments demonstrate that ChromaCode achieves remarkable raw throughputs of >700 kbps, data goodputs of 120 kbps with BER of 0.05, and with fully imperceptible flicker for viewing proved by user study, which significantly outperforms previous works.

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