Iterative Spectral Image Reconstruction-Based Display Field Communication Using Advanced Receiver

Display field communication (DFC) is an imper-ceptible display-to-camera (D2C) communication paradigm in which data is conveyed by taking advantage of the spectral domain properties of individual video frames. The data are embedded in the frequency domain of an image frame and the data-embedded image is then displayed on an electronic screen. The display screen is subsequently been captured by a camera receiver and the data are decoded. Although DFC successfully transmits and decodes data from the frequency domain of images, it uses reference frames to reliably decode the data, which significantly degrades the achievable data rate of the system. In this paper, we propose a technique termed pilot-assisted iterative spectral image reconstruction, which eliminates the use of reference frames. In particular, a $256\times 256$ pixel grayscale image is used for embedding the data that consists of information bits and pilots. The pilot symbols were used for the reconstruction of the reference frames at the receiver. More importantly, the proposed method reconstructs the spectral image frames iteratively using the reliable information symbol estimates fed back by the camera decoder that are being used as fresh pilots in subsequent iterations. After successful reference image reconstruction, the data are decoded using an advanced minimum mean-square error (MMSE) receiver. From numerical simulations, we show that the proposed method significantly boosts the data transmission capacity of the DFC system over the conventional DFC that uses reference frames.