Application of dot shifting watermark and data hiding to personalized stamps

• Main Author: 蔡致邠
• Other Authors: 王希俊
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/e55xx8

碩士 === 國立臺灣師範大學 === 圖文傳播學系 === 97 === The double encryption based on digital halftoning and dot shifting is stud-ied in this research. This double encryption technology can be applied to the design of personalized stamps with combined features of digital watermark and data hiding. The hidden watermark can be extracted by an optical decoder, and a part of stamp can be scanned through the high resolution scanner to get encrypted data. The stamp with hidden watermark in the study is output at 150LPI, and the watermark can’t be duplicated by the photocopier to achieve the anti-counterfeiting feature. In order to achieve multiple encryption and to make the personalized stamps more interesting, the hidden watermark and encrypt data can be decoded with the optical decoder and the computer pro-grams, respectively.