Date

Place

[54-4]
11:50 ~ 12:05
Title:Decoding Waving-Hand Steganography by Use of an Optical Chopper
Masashi Takahashi and Hirotsugu Yamamoto (Utsunomiya Univ., Japan)
Abstract: We propose a kind of steganography, called by waving-hand steganography, by use of a high-frame-rate LED display. The proposed steganography employs a high-frame-rate LED display to embed a secret image in successive 4 fields that are changed at 480 fps. Secret characters are embedded so that they are unnoticeable under normal viewing. When the LED display is viewed through a waving hand, the embedded information become noticeable. In this study, we have investigated to clarify the frequency range of shuttering that decodes the embedded information by use of an optical chopper. We have used two types images displayed sequences. For the 120-Hz sequence, embedded information was clearly decoded within the range from 115 Hz to 130 Hz. Then, whole shape of the embedded information became visible at 90Hz, and contrast of the decoded image was reduced around 200 Hz. On the contrary, for the 240-Hz sequence, the embedded information was invisible around 120 Hz. The embedded information was clearly decoded at 240 Hz. Then, contrast of the decoded image was reduced around 270Hz. Thus, we have identified the frequency ranges of an optical chopper to decode the waving-hand steganography. The experimental results suggest possibility of time-domain multiple information embedding.
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