A new displaying technology for information hiding using temporally brightness modulated pattern

We propose a new display system technology that can hide secret information behind a displayed image, while simultaneously satisfying both high invisibility and readability requirements. The hidden information is a kind of binary image including characters, and various kinds of patterns, i.e., quadratic residue (QR) codes. This technique uses a temporally bright modulated invisible pattern in a moving image, or video. Frame images over some periods are summed up when read out, enhancing the contrast of the invisible pattern to make it visible. We also propose a new method to solve an issue that occurs due to asynchronous operations of the display and video camera, which is a technique that was achieved by using time shift sampling. The hidden binary image could be read out according to experiments that we conducted to confirm the results. Moreover, the patterns used in this technique were decidedly invisible when laid behind the main images, which suggested the proposed technology was highly feasible in practical applications according to this confirmation.