| Summary: | 碩士 === 國立中興大學 === 資訊管理學系所 === 104 === The rapid development of science and technology promotes the popularity of mobile networks. People often use the internet media to deliver messages. Since the digital data are effortlessly imprinted, the problems of plagiarism and falsification from hackers are often appear. To prevent these problems, information security issues is very important. Protecting secret data to be stolen and changed is important. One of the technical is image hiding. This purpose is to provide a higher amount of information hiding and takes into account the image quality. There is a problem in many histogram shifting information hiding techniques.
Only if the secret data with bit 1 are embedded in a cover image, the gray-levels of the pixels embedding the secret data in the cover image will be changed; otherwise, the gray-levels of the pixels embedding the secret data with bit 0 in the cover image will not be changed. In this study, a strategy is proposed in which the secret data can be transformed by the Exclusive-OR Logic Transform (XOR-LT) operation before embedded.
In this method, the quality of the stego image can be promoted since fewer secret data with bit 1 are embedded in the cover image. Histogram shifting information hiding techniques generally embed the secret data in the pixels with the prediction error equal to that at the highest peak point in the prediction error histogram.
In this study, a GAP-MED prediction method is proposed to predict the gray-levels of the pixels in a cover image. The method can be used to heighten the highest peak in the prediction error histogram so that the information hiding rate can be increased.
In this study, XOR-LT and GAP-MED prediction method are also applied to histogram shifting information hiding. The experimental results demonstrate that XOR-LT can improve the stego image quality. Using GAP-MED Prediction can heighten the highest peak in the prediction error histogram so the information hiding rate can be increased.
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