Data Hiding based Compression Mechanism for 3D Models

Hui Li Parag Agarwal Balakrishnan Prabhakaran

Department of Computer Science,

The University of Texas at Dallas, TX 75083

Email {Hui li, parag.agarwal} @ student.utdallas.edu, praba@utdallas.edu Different compression methods [2] such as progressive meshes and single refinement mesh compression exist for mesh representation for 3D models and improving them is a challenge. This paper is a step in this direction, where we show that data hiding methods can be used to significantly improve the compression achieved for such methods. 3D meshes are made up of connectivity (edge set E) and geometric (vertices set V) information. The data hiding method should provide a very high embedding rate in order to achieve a desirable compression ratio. This can be modeled mathematically, given ‘V’ points or vertices in 3D space; for a given compression ratio we use ‘K’ points and hide rest of the connectivity and geometric information inside it. These points are termed as the encoding points and the encoded information is termed is the compressed information.

Hiding capacity (K) ≥ Size of (V – K) + Size of (E) (1) In order to do so, we need to make sure that ‘K’ provides a hiding capacity, which is large enough to encode this data (see equation 1). Since data hiding methods result in distortions, it is imperative to minimize these distortions as well. In order to handle such challenges, we propose to use data hiding mechanism (multilevel quantization index modulation MQIM) [1] for improving the compression mechanism for existing schemes such as progressive mesh representation and single refinement mesh compression schemes. The paper estimates the bounds on the compression in terms of the hiding capacity offered by MQIM [1]. Experimental results show that the proposed method can achieve a high compression ratio (0.3-0.5) on the encoded data stream with small distortion. REFERENCES [1] H Li, P. Agarwal and B. Prabhakaran, “A Multi-level Quantization Index Modulation based Data hiding scheme”, Technical Report (UTDCS-04-07), Jan 2007

[2] Jingliang Peng, Chang-Su Kim and C.-C. Jay Kuo, ‘Technologies for 3D mesh compression: A Survey’, Journal of Visual Communication and Image Representation, Volume 16, Issue 6, December 2005, Pages 688-733

2007 Data Compression Conference (DCC'07)0-7695-2791-4/07 $20.00 © 2007