Summary
The 2018 International Symposium on Information Theory and Its Applications　(ISITA2018)
2018
Session Number:Tu-AM-1-2
Session:
Number:Tu-AM-1-2.4
A Watermarking Method for Embedding into the External Shapes of Objects
Hiroshi Yamamoto, Kazuki Sano,
pp.321-325
Publication Date:2018/10/18
Online ISSN:2188-5079
DOI:10.34385/proc.55.Tu-AM-1-2.4
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Summary:
In recent years, low-cost 3D printing has rapidly spread among general consumers. On the other hand, the fact that once an adversary obtains the data, he can produce any number of reproductions has been pointed out as one of the critical issues confronting 3D printing. There is existing research in which cavities that express embedded information are made in the interior of 3D objects. This method aims at embedding information into a legitimately created object, however, it is not robust against an attack where an adversary obtains the external shape of the object by 3D scanning and reproduces the object, or an attack where an adversary simply makes a mold of the object and produces copies by casting. In this paper, we propose a scheme whereby information is embedded into the external shapes of objects. Attackers cannot change the information without changing the external shapes of the objects when they make copies of the original 3D objects. In the proposed scheme, we define the pseudo rotation axis for a 3D object and cutting planes that are orthogonal to the axis, and then we embed information into the maximum values of the radii of the cross sections. To modify the maximum values of the radii, we scale x coordinates and y coordinates of vertices of polygons. The scale factor continuously varies according to the z coordinate of the vertex in order to reduce the distortion of the object. We conduct experiments in which actual 3D objects are made and into which information is embedded using the proposed method and extracting the information from only the object without any metadata.We show that transmission of information with only the printed 3D object is possible using the proposed scheme without notable distortion of the object.