Compensating Image Overlay 16QAM Using Dual Cameras for Rolling Shutter-Based Screen Camera Communication

Abstract

Image overlay uplink screen camera communication consisting of a small display with LED backlight modulation and an indoor rolling shutter camera has been studied. A previous study demonstrated that image overlay QPSK was achieved by compensating pixel values of the overlaid image using dual cameras. However, even after the compensation, variation in the pixel values remained, making it difficult to realize further M-ary modulation. In this study, a compensation method taking both the overlaid image and backlight modulation into account is proposed. Constellation, error vector magnitude, and bit error rate for image overlay 16QAM are experimentally evaluated using dual cameras.