Multiuser Two-Dimensional Display Field Communication Using Orthogonal Frequency Subband Partitioning

Display field communication (DFC) enables an electronic display to transmit hidden data to a camera while preserving the displayed visual content, but existing two-dimensional (2D) DFC studies have focused on single display–camera links. This paper proposes a simple multiuser 2D-DFC scheme in which one display conveys independent data streams to multiple camera users through nonoverlapping rectangular frequency subbands. User data are modulated using quadrature amplitude modulation, and are multiplicatively embedded into the 2D discrete Fourier transform coefficients of the input image. A reference-frame receiver with frequency-domain estimation is evaluated by using Monte Carlo simulation under equal and heterogeneous camera-noise conditions. For two users sharing a fixed total subband, the proposed scheme achieves nearly the same aggregate uncoded goodput and symbol-error performance as single-user 2D-DFC while dividing the available rate between the users. When a fixed subband is assigned to each user, the aggregate goodput increases from approximately 3 to 12 kbps as the user count increases from one to four. The corresponding mean peak signal-to-noise ratio decreases from about 50.9 to 45.8 dB, and the structural similarity index measure is higher than 0.9996. These results demonstrate a low-complexity multiple-access extension of 2D-DFC and quantify the tradeoff between throughput and visual quality.