| Summary: | 碩士 === 國立中正大學 === 資訊工程所 === 98 === Because the development of Internet, a large amount of data is wildly transmitted through Internet, including text, audio, image and so on. In order to reduce the bandwidth and memory size when sending and receiving, some compression techniques are developed. For instance, Vector Quantization (VQ) and JPEG are image compression methods. Moreover, some information does not allow to be published; therefore, the technique of data hiding has been developed recently. Data hiding can use different information type to hide data. Image hiding is a data hiding method which utilizing the image character to embed secret data. Further, the extraction of image hiding can recover the stego-image to original image lossless, which is called “reversible data hiding”. On the contrary, the stego-image is recovered to original image lossy, which is called “non-reversible data hiding”. In this thesis’s last two methods are emphases on reversible data hiding; therefore, the methods can apply multiple-layer embedding to increase the capacity. First method applies heuristic and index table shifting to embed data; and second methods uses horizontal embedding and vertical embedding in the spatial image. Third method applies horizontal and vertical embedding in the difference image.
Embedding capacity and image quality are the schemes to estimate the embedding method stand or fall. The experimental results indicate the capacity and image quality are better than other compared methods. Especially for second method and third method, not only maintain good image quality, but also increase lots of embedding capacity after multiple-layer embedding.
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