In this paper,a new approach is proposed to determine whether the content of an image is authentic or modified with a focus on detecting complex image tampering.Detecting image tampering without any prior information ...In this paper,a new approach is proposed to determine whether the content of an image is authentic or modified with a focus on detecting complex image tampering.Detecting image tampering without any prior information of the original image is a challenging problem since unknown diverse manipulations may have different characteristics and so do various formats of images.Our principle is that image processing,no matter how complex,may affect image quality,so image quality metrics can be used to distinguish tampered images.In particular,based on the alteration of image quality in modified blocks,the proposed method can locate the tampered areas.Referring to four types of effective no-reference image quality metrics,we obtain 13 features to present an image.The experimental results show that the proposed method is very promising on detecting image tampering and locating the locally tampered areas especially in realistic scenarios.展开更多
Because there are different modification types of deleting characters and inserting characters in text documents, the algorithms for image authentication can not be used for text documents authentication directly. A t...Because there are different modification types of deleting characters and inserting characters in text documents, the algorithms for image authentication can not be used for text documents authentication directly. A text watermarking scheme for text document authentication is proposed in this paper. By extracting the features of character cascade together with the user secret key, the scheme combines the features of the text with the user information as a watermark which is embedded into the transformed text itself. The receivers can verify the integrity and the authentication of the text through the blind detection technique. A further research demonstrates that it can also localize the tamper, classify the type of modification, and recover part of modified text documents. The aforementioned conclusion has been proved by both our experiment results and analysis.展开更多
基金Sponsored by the National Natural Science Foundation of China(Grant No.60971095 and No.61172109)Artificial Intelligence Key Laboratory of Sichuan Province(Grant No.2012RZJ01)the Fundamental Research Funds for the Central Universities(Grant No.DUT13RC201)
文摘In this paper,a new approach is proposed to determine whether the content of an image is authentic or modified with a focus on detecting complex image tampering.Detecting image tampering without any prior information of the original image is a challenging problem since unknown diverse manipulations may have different characteristics and so do various formats of images.Our principle is that image processing,no matter how complex,may affect image quality,so image quality metrics can be used to distinguish tampered images.In particular,based on the alteration of image quality in modified blocks,the proposed method can locate the tampered areas.Referring to four types of effective no-reference image quality metrics,we obtain 13 features to present an image.The experimental results show that the proposed method is very promising on detecting image tampering and locating the locally tampered areas especially in realistic scenarios.
基金Supported by the National Natural Science Foun-dation of China (60373062 60573045)
文摘Because there are different modification types of deleting characters and inserting characters in text documents, the algorithms for image authentication can not be used for text documents authentication directly. A text watermarking scheme for text document authentication is proposed in this paper. By extracting the features of character cascade together with the user secret key, the scheme combines the features of the text with the user information as a watermark which is embedded into the transformed text itself. The receivers can verify the integrity and the authentication of the text through the blind detection technique. A further research demonstrates that it can also localize the tamper, classify the type of modification, and recover part of modified text documents. The aforementioned conclusion has been proved by both our experiment results and analysis.
