Marked ghost imaging

In recent years, ghost imaging has been widely applied in various areas, such as optical security. Here, we report how an object and multiple hidden marks can be simultaneously recovered by using only one rebuilt reference intensity sequence in ghost imaging. The reconstructed object can be clearly observed during the decoding, and multiple marks can be effectively hidden. This unique characteristic is established for ghost imaging system clue to random selections of pixels from each reference intensity pattern, which also guarantees high security. This finding may open up a different research perspective for ghost-imaging-based security system.