Some Studies On Digital Watermarking Algorithm For Protecting The Copyright Of Chinese Characters

With the development of China,the applications of Chinese characters are more and more extensive,in which the copyright of Chinese characters in digital videos and digital texts are noticed widely.At the same time,the digital products are frequently attacked,such as the copyright is illegally infringed and the content is maliciously tampered,especially the tempered Chinese characters.Therefore,it is necessary to propose digital watermarking algorithms to protect the copyright of Chinese characters in different application scenarios.To resolve the problem,this paper proposed some studies on digital watermarking algorithm for protecting the copyright of Chinese characters:(1)A zero-watermarking algorithm for protecting Chinese characters without being tampered.This paper proposed a zero-watermarking algorithm for protecting Chinese characters without being tampered.This algorithm contains caption detection method with background segmenting based on Chinese characters and video zero-watermarking scheme based on Chinese image matching.Firstly,due to the directional feature of Chinese basic strokes,four differential first order filters are designed to filter the video frames,and the morphological operation method is adopted to detect the Chinese caption area.Secondly,the improved two OTSU method is used to segment the image background,we will get the Chinese zero-watermark without background and register the standard zero-watermark in the third certification party.Finally,after gaining zero-watermark from the unverified video through the above methods,it is time to do the zero-watermarking similarity matching with the original one registered in the third certification party.Experiment results show that the proposed video zero-watermarking algorithm has good robustness for the video attacks such as frame rate changing,recoding,frame dropping,transcoding and tampering text.(2)A blind watermarking algorithm for copyright protection of Chinese text.This paper proposed a blind watermarking algorithm for copyright protection of Chinese text,which can resist the print-scan attack.In the embedding process,all the distances between Chinese characters in the original document are detected by Microsoft Word,and adjusted according to the watermark information,such as the former is enlarged and the latter is reduced the equal value,or the opposite.In addition,parity checking and multi embedding mechanism are adopted in the watermarking.In the extracting process,firstly,the text image after printing and scanning will be tilt corrected.Secondly,on the basis of character segmentation method,punctuation,numbers and Chinese characters are segmented and identified,and then the inter-character spaces are extracted.Finally,the watermark information is transformed from standardized inter-character spaces.The experimental results prove that the layouts of documents are unchanged,and the watermark information can be extracted from the printed-scanned images.Meanwhile,the process of algorithm is widely practical because of no operation of manually selecting characters.