3D object watermarking by a 3D hidden object.

In this paper we present a method to watermark a 3D object with another hidden 3D object using digital holography. The watermark or the hidden information is a 3D object that is embedded in the digital hologram of a 3D host object. The digital holograms are obtained optically by phase shift interferometery. The hologram of the hidden 3D object is double phase encoded before embedding it to the host 3D object hologram. Then, the watermarked hologram is double phase encoded again using different set of codes. The resultant watermarked hologram is very secure because of the multi-key nature of the watermarking process. We discuss the effect of distortion caused by hologram quantization and occlusion of some of the hologram pixels. We present tests to illustrate the effect of using a window of the hologram to reconstruct the hidden 3D object and the host 3D object. Both mathematical analysis and simulations are presented to illustrate the system performance. To the best of our knowledge, this is the first report of embedding a 3D objects within another 3D object.