Construction of Autostereograms Taking into Account Object Colors and Its Applications for Steganography

Information on appearances of three-dimensional objects are transmitted via the Internet, and displaying objects plays an important role in a lot of areas such as movies and video games. An autostereogram is one of the ways to represent three-dimensional objects taking advantage of binocular parallax, by which depths of objects are perceived. In previous methods, the colors of objects were ignored when constructing autostereogram images. In this paper, we propose a method to construct autostereogram images taking into account color variation of objects, such as shading. We also propose a technique to embed color information in autostereogram images. Using our technique, autostereogram images shown on a display change, and viewers can enjoy perceiving three-dimensional object and its colors in two stages. Color information is embedded in a monochrome autostereogram image, and colors appear when the correct color table is used. Our technique can also be used for steganography to hide color information. Moreover, file size gets smaller than that of an original autostereogram image because indexed colors are used. Therefore, the 3D images constructed using our method are useful for transmission through the cyberworld.