Now showing 1 - 10 of 66
  • Publication
  • Publication
    Framework for combined video frame synchronization and watermark detection
    ( 2007)
    Hauer, E.
    ;
    Bölke, T.
    ;
    Steinebach, M.
    Most of the MPEG watermarking schemes can only be embedded into I-frames. The other frames will not be marked. Different attacks like frame rate changing can change the frame type of the marked I-frames. Thus the watermark could be detected from wrong I-frames. Due to these attacks an important issue of digital watermarking solutions for MPEG video is the temporal synchronization of the video material to the proportions before the attacks to detect the watermark successfully. The synchronization information can be embed as part of the information watermark or as a second watermark. The weakness point is with the destruction of the synchronization information the watermark can not be detected more. We provide a solution which analyzes the I-frames based on a robust image hash system. The hash solution was developed for JPEG images and can also be used for MPEG I-frames because of their similar structure. The hash values are robust against common manipulations, like compr ession, and can be used to detect the marked frames also after manipulations at the video material. We analyze the usability of the image hash system and develop a concept based on video and MPEG properties.
  • Publication
    Suche nach Urheberrechtsverletzungen in Internet-Tauschbörsen mittels Digitaler Wasserzeichen
    ( 2006)
    Diener, K.
    ;
    Wolf, P.
    ;
    Steinebach, M.
    ;
    Wiedling, H.-P.
  • Publication
  • Publication
    Semi-fragile watermarking for image authentication with high tampering localization capability
    ( 2006)
    Liu, H.
    ;
    Steinebach, M.
    In this paper we propose a novel watermarking scheme for image authentication. A high localization of tampering detection is achieved by applying a random permutation process where every embedded watermark bit verifies random image positions instead of a local image block. Thereby the resolution of tampering detection is significantly improved in comparison to existing solutions while keeping the payload low. Furthermore, the proposed scheme doesn't embed the watermark locally but distributes it into the suitable embedding wavelet coefficients, avoiding embedding in smooth regions. Therefore, the scheme is intrinsically secure to block-based local attacks and retains high fidelity of the watermarked image. Scalable sensitivity of tampering detection is enabled in the authentication process. Analysis and experimental results demonstrate the performance and effectiveness of the scheme for image authentication.
  • Publication
    Audio integrity protection and falsification estimation by embedding multiple watermarks
    ( 2006)
    Gulbis, M.
    ;
    Müller, E.
    ;
    Steinebach, M.
    The recognition of digital audio data manipulation is a challenge addressed by various fragile and contentfragile watermarking algorithms. But so far none of the approaches provides satisfying results with respect to manipulation detection. Especially distinguishing malicious attacks from allowed post production operations is still an open issue. We introduce a novel watermarkingbased approach for audio data falsification recognition. We embed multiple watermarks with various characteristics into the audio data to be protected. By analyzing the quality of the retrieved watermarks we obtain information about the nature of the manipulation of the audio data. In comparison to known feature-embedding algorithms, this is rather a forensic approach using watermarking as a hint. Our method is verified using several audio data sets.
  • Publication
    Digital watermarking for image authentication with localization
    ( 2006)
    Liu, H.
    ;
    Steinebach, M.
    In this paper we propose a novel watermarking scheme for image authentication. A high localization of tampering detection is achieved by applying a random permutation process where every embedded watermark bit verifies random image positions instead of a local image block. Thereby the resolution of tampering detection is significantly improved in comparison to existing solutions while keeping the payload low. Furthermore, the proposed scheme doesn't embed the watermark locally but distributes it into the suitable embedding wavelet coefficients, avoiding embedding in smooth regions. Therefore, the scheme is intrinsically secure to block-based local attacks and retains high fidelity of the watermarked image. Scalable sensitivity of tampering detection is also enabled in the authentication process. Experimental results demonstrate the performance and effectiveness of the scheme for image authentication.
  • Publication
    Temporal synchronization of marked MPEG video frames based on image hash system
    ( 2006)
    Hauer, E.
    ;
    Steinebach, M.
    Most of the MPEG watermarking schemes can only be embedded into I-frames. The other frames will not be marked. Different attacks like frame rate changing can change the frame type of the marked I-frames. Thus the watermark could be detected from wrong I-frames. Due to these attacks an important issue of digital watermarking solutions for MPEG video is the temporal synchronization of the video material to the proportions before the attacks to detect the watermark successfully. The synchronization information can be embed as part of the information watermark or as a second watermark. The weakness point is with the destruction of the synchronization information the watermark can not be detected more. We provide a solution which analyzes the I-frames based on a robust image hash system. The hash solution was developed for JPEG images and can also be used for MPEG I-frames because of their similar structure. The hash values are robust against common manipulations, like compr ession, and can be used to detect the marked frames also after manipulations at the video material. We analyze the usability of the image hash system and develop a concept based on video and MPEG properties.
  • Publication
    A digital watermark for vector-based fonts
    ( 2006)
    Thiemert, S.
    ;
    Steinebach, M.
    ;
    Wolf, P.
    In this paper we present a blind watermarking scheme for vector-based fonts. The scheme can be used for authenticating the copyright holder as well as for identifying customers of fonts. We slightly modify the symmetry between curve pairs to embed a binary message. The watermark is invisible and robust against conversion into other vector-based font formats. An implementation for TrueType-Fonts was evaluated by typeface designers. Based on the blind watermarking scheme we discuss an extension to a non-blind watermark, which is in addition robust against uniform scaling.
  • Publication
    Using entropy for image and video authentication watermarks
    ( 2006)
    Thiemert, S.
    ;
    Sahbi, H.
    ;
    Steinebach, M.
    There are several scenarios where the integrity of digital images and videos has to be verified. Examples can be found in videos captured by surveillance cameras. In this paper we propose a semi-fragile watermarking scheme, which can be applied on still images as well as on digital videos. We concentrate on the protection of I-frames in compressed MPEG-1/2 videos. We use the entropy of the probability distribution of gray level values in block groups to generate a binary feature mask, which is embedded robustly into an adjacent I-frame. The approach can distinguish between content-preserving and content-changing manipulations. Positions of content-changing manipulations can be localized. We provide experimental results to analyze the effectiveness of the scheme. In the evaluation part we concentrate on the robustness against content-preserving and the sensitivity to content-changing manipulations.