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Please use this identifier to cite or link to this item:
http://asiair.asia.edu.tw/ir/handle/310904400/2698
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| Title: | A DATA HIDING SCHEME BASED ON VQ AND SOC |
| Authors: | ku wei han |
| Contributors: | Department of Photonics and Communication Engineering |
| Keywords: | Steganography, Information hiding, Date hiding, Cover image, Stego-image, Least-Significant-Bits substitution (LSB), Vector Quantization compression (VQ), Search-Order Coding (SOC). |
| Date: | 2007 |
| Issue Date: | 2009-11-16 08:04:15 (UTC+0) |
| Publisher: | Asia University |
| Abstract: | In recent years, the computer and network communication techniques have been developed quickly, people attach great importance to secret communication. For this reason, information hiding was being proposed. As the information hiding techniques go far, it is mainly classified into two categories: copyright marking and steganography. Copyright marking is used to embed the copyright information, like a signature or a trademark, into the cover image for ensuring the copyright. The emphasis on copyright marking is that the watermark hidden in the cover image must be able to be retrieved, even if the stego-image has been applied lots manipulations such as cropping, lossy compression, resize, etc. Watermark is usually very small, and composes of visible watermarking and imperceptible watermarking.
Steganography is different from watermarking. The goal of steganography is how to embed secret data into the cover image, let the interceptors neither feel something peculiar nor want to attack the stego-image. In the other word, steganography is to provide a secret communication. The key issues in steganography are how to embed more secret data and to remain the stegoimage?s good quality. The technique of data hiding in images can be classified into two categories, i.e., data hiding in spatial domain schemes and data hiding in frequency domain schemes.
Neither data hiding in spatial domain schemes nor data hiding in frequency domain schemes can be used in other domain. In this thesis, we propose a new steganographic scheme based on Vector Quantization compression (VQ) and Search-Order Coding (SOC) for gray-level images. The embedded capacity of this scheme is higher than the others in which are based on VQ and the quality of stego-image is acceptive. In general, the capacity of the schemes based on VQ are usually 1-bit per block. In 2004, Yu et al proposed a scheme to increase the capacity to 3-bit per pair of blocks. In our scheme, we used multiple codebooks and chose the combinations of per pair of blocks, to embed the secret data. The capacity was increased to 6-bit per pair of blocks, and the quality is the same as Yu et al.?s scheme. |
| Appears in Collections: | [光電與通訊學系] 博碩士論文
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