| Summary: | 碩士 === 朝陽科技大學 === 網路與通訊研究所 === 93 === Abstract
In this thesis, we proposed a novel stegangraphy method utilizing the features obtained from Discrete Wavelet Transform (DWT). Applying a secure coding scheme, the secret messages are embedded into the three high frequency sub-bands of DWT coefficients. Since the portion which human eyes are sensitive to, the low frequency sub-band, remains unaltered, the image quality after secret messages embedding is increased. According to different needs of embedding capacity, we explain the embedding method in five cases. In addition to high embedding capacity and image quality, the proposed approach provides respectable security as well. Because the original secret messages are arithmetically manipulated before embedding, they would not be recovered directly from the rightmost Least Significant Bits (LSBs) of coefficients in any sub-band.
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