| Summary: | 碩士 === 國立臺北科技大學 === 電腦與通訊研究所 === 93 === Information hiding in multimedia data has drawn a lot of attention in recent years. A message is hidden in digital images, video and audio in an imperceptible manner so as not to interfere is hidden with the normal usage of these host media files. The hidden information related to content protection is usually termed Digital Watermark. The recent proliferation of the information-hiding research mostly comes from the development of digital watermarking techniques to meet the pressing need of content protection. The other interesting application is to transmit a large volume of data covertly in a multimedia file via information hiding. The objective in this application is to conceal the very existence of the hidden information using the innocuous multimedia data as camouflage. Data hiding under this scenario is often termed Steganography.
In thesis research, we focus on steganography in JPEG-2000. We investigate information hiding technique in the state-of-the-art still image codec, JPEG-2000. The thesis consists of two major objectives. The first objective is to develop a secure and high-volume information hiding scheme. The second objective is to develop a efficient information hiding scheme in limited bit-rate constraint at lossy compression mode.
We proposed a secure information hiding scheme with the subband-based coefficients permutation encrypting methods and coefficient-wise based XOR encrypting method with the HH2 subband key to achieve the first objective. Then, we proposed a prioritized inclusion method for coding passes at specific code block to achieve the second objective. Additionally, we also consider some human visual characteristics to improve the resulting stego-image quality. Finally, a joint compression/information-hiding scheme is proposed to finish these objectives.
We examined the proposed information hiding scheme at the lossless and lossy JPEG-2000 compression mode. 1bpp and 0.5bpp bit-rate constraints are adopted at lossy compression mode. Several experimental results demonstrate the practicability and the decent performance of the proposed algorithms.
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