Spatial Frequency Modulation for Display-Camera Communication

Display-camera communication (DCC) is one of visible light communication (VLC) techniques using an LED display and a camera. Conventional methods hide data bits by dynamically changing luminance intensity of image blocks. However, this approach still suffers from noticeable flickering artifacts. In this paper, we proposed a novel spatial frequency modulation method for display-camera communication. The proposed method hides a bit by modulating spatial frequency of an image block, which is actually implemented by blurring and sharpening. Discrete Cosine Transform (DCT) is applied to an image block, and its high frequency coefficients are either boosted (sharpened) or zero-padded (blurred). Experimental results demonstrate that the proposed method can achieve larger throughput and higher transmission accuracy, compared to the existing luminance methods.