Embedding information in three-dimensional geometric model

Details Embedding information in three-dimensional geometric model Embedding information in three-dimensional geometric model

1998-05-22

2001-03-13

Johns, Andrew W. (Department: 2621)

Image analysis

Applications

C382S154000, C345S419000

Reexamination Certificate

active

06201881

ABSTRACT:

FIELD OF THE INVENTION
The present invention is directed to the field of information embedding. It is more specifically directed to hiding data in a geometric model.
BACKGROUND OF THE INVENTION
The providing image and voice signals on the internet as digital information has increased. Because this digital information can be easily reproduced, the embedding proprietary information and accounting information in the digital information is studied. The operation for such embedding of information is referred to as information embedding, information hiding, or watermarking.
A triangular mesh model is a three-dimensional-structure frequently used to transfer 3D data on the internet. Recently, 3D data can be displayed by browsers of various companies and therefore, it is estimated that this type of utilization of 3D data will increase. At the same time, it becomes an issue how to attach proprietary information and other accessory pieces of information (e.g. preparation date, preparer, and version) to the 3D data when distributing the 3D data.
Preparation of 3D data frequently requires the investment of a lot of time money and an aesthetic sensibility similar to that needed for photos and pictures. In the case of this type of data, the following copyright information is embedded in a 3D data file as a text comment.
COPYRIGHT (C) BY IBM JAPAN, LTD. 1996
IBM Japan, Ltd. has been authorized to freely distribute these Datasets. They are provided for unlimited use in existing or modified form. The actual Dataset (i.e. geometry) may not, however, be resold in existing or modified form.
However, the above copyright indication method is defenseless against a wicked revision by a third party. Because copyright information is erased or becomes invalid by performing the following.
First, it is possible to easily erase information written in a file as a text by text editing. Even if a text comment is enciphered by the PGP or DES method, it is easy to remove the enciphered information as if the information was not enciphered. Therefore, it is impossible to prevent modification of a copyright notice.
Moreover, when using a format conversion program for converting certain 3D source data into an object form for the three-dimensional geometric model a copyright notice is erased in the conversion and only the following character string is left.
# Fri Jul 14 12:44:19 1997
#
# Object converted by XXX-to-obj
#
At present, there is not any effective method for embedding proprietary information such as the signature of a proprietor or preparer in a model. Therefore it is an object of the present invention to embed various pieces of information in a three-dimensional geometric model.
Another object of the present invention is to embed information in a three-dimensional model for one or more of the following purposes:
Authentication of preparer
Confirmation of proprietor
Confirmation of receiver
Prevention of onerous reception
Control of preparation date
Stock control
Prevention of prohibited copy
Restraint of prohibited copy
Recording of secret information
A further object of the invention is to accurately disembed the information embedded in the above three-dimensional geometric model.
SUMMARY OF THE INVENTION
The present invention uses a method for embedding various pieces of information in the three-dimensional geometric model under a visible or invisible state by changing geometric parameters of the three-dimensional geometric model. A three-dimensional geometric model normally comprises a polyhedron, a line, a set of points, or a curved surface which is a primitive (component) of the model. Moreover, each primitive is defined by geometric parameters. Therefore, the entire geometric shape of a three-dimensional geometric model is defined by a set of many geometric parameters.
In the case of the present invention, information is embedded by changing the geometric parameters of a plurality of primitives constituting a three-dimensional geometric model. Moreover, the present invention provides a method for embedding information by dividing geometric parameters into numerical parameters and topology.
A numerical parameter includes two nondimensional values for defining a vertex coordinate value, the length of a line, the area of a polygon, the volume of a polyhedron, or a triangle. Information is embedded by changing these values.
It is also possible to use the ratio between these two nondimensional values for defining a vertex coordinate value, the length of a line, the area of a polygon, the volume of a polyhedron, or a triangle as a numerical parameter.
The embedded information is disembedded by detecting the above changed geometric parameters.
Information is also embedded by changing topology for determining a vertex connective relation or the like.
Information can be embedded by combining the numerical parameters with the topology because change of the numerical parameters and change of the topology are independent from each other.
In this specification, a polyhedral model and a curved-surface model represent the following surface models.
Polyhedral model
Model comprising a polyhedron, line, and a set of points (Including both cases in which a vertex has connectivity and it does not have connectivity)
Curved-surface model
Model including a curved surface in addition to a polyhedron, line, and a set of points


REFERENCES:
patent: 5636292 (1997-06-01), Rhoads
patent: 6044168 (2000-03-01), Tuceryan et al.
Ohbuchi et al., “Watermarking Three-Dimensional Polygonal Models,” Proc. 5th ACM Int. Conf. on Multimedia, Nov. 1997, pp. 261-272.
Li et al., “3-D Motion Estimation in Model-Based Facial Image Coding,”IEEE Trans. on Pattern Analysis and Machine Intelligence, vol. 15, No. 6, Jun. 1993, pp. 545-555.
Essa et al., “A Vision System for Observing and Extracting Facial Action Parameters,”IEEE Proc. CVPR '94, 1994 IEEE Computer Society Conf. on Computer Vision and Pattern Recognition, Jun. 21-23, 1994, pp. 76-83.

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