At the same time, it is possible to detect and localize small image manipulations. Compression-compatible fragile and semifragile tamper detection Author s : Lisa M. Marvel; George W. Hartwig Jr.
Boncelet Jr. Show Abstract. In this paper, we present two tamper-detection techniques. The first is a fragile technique that can detect the most minor changes in a marked image using a DCT-based data hiding method to embed a tamper-detection mark. The second is a semi-fragile technique that detects the locations of significant manipulations while disregarding the less important effects of image compression and additive channel noise.
Both techniques are fully described and the performance of each algorithms demonstrated by manipulation of the marked images. In this paper, we propose a semi-fragile watermarking technique that accepts JPEG lossy compression on the watermarked image to a pre-determined quality factor, and rejects malicious attacks.
- Thierry Pun - Google Scholar Citations!
- Fighting to Forget (Fighting, Book 3);
- RF/Microwave Interaction with Biological Tissues?
The authenticator can identify the positions of corrupted blocks, and recover them with approximation of the original ones. In addition to JPEG compression, adjustments of the brightness of the image within reasonable ranges, are also acceptable using the proposed authenticator.
CN1737819A - 一种通用的数字图像隐形信息检测方法 - Google Patents
They are deterministic so that no probabilistic decision is needed in the system. The first property shows that if we modify a DCT coefficient to an integral multiple of a quantization step, which is larger than the steps used in later JPEG compressions, then this coefficient can be exactly reconstructed after later acceptable JPEG compression.
The second one is the invariant relationships between two coefficients in a block pair before and after JPEG compression. Therefore, we can use the second property to generate authentication signature, and use the first property to embed it as watermarks. There is no perceptible degradation between the watermarked image and the original.
A New Approach in Digital Image Watermarking Using Fractal Model in DWT Domain
In additional to authentication signatures, we can also embed the recovery bits for recovering approximate pixel values in corrupted areas. Our authenticator utilizes the compressed bitstream, and thus avoids rounding errors in reconstructing DCT coefficients. Experimental results showed the effectiveness of this system. The system also guaranies no false alarms, i. Detection of image alterations using semifragile watermarks Author s : Eugene T. Lin ; Christine I.
Thierry Pun - Google Scholar Citations
Podilchuk; Edward J. Digital watermarking research has generally focused upon two classes of watermarks, fragile and robust. Robust watermarks are designed to be detected even after attempts are made to remove them. Fragile watermarks are used for authentication purposes and are capable of detecting even minute changes of the watermarked content. Unfortunately, neither type of watermark is ideal when considering 'information preserving' transformations such as compression which preserve the meaning or expression of the content and 'information altering' transformations such as feature replacement which change the expression of the content.
In this paper we describe a semi-fragile watermark for still images that can detect information altering transformations even after the watermarked content is subjected to information preserving alterations. Distortion-bounded authentication techniques Author s : Nasir D.
https://desorchosul.gq Memon ; Poorvi L. Yeung Show Abstract. Authentication techniques provide a means of ensuring the integrity of a message. The recent proliferation of multimedia content has led to a need for developing authentication mechanisms. Although, authentication techniques have been studied for many decades, multimedia authentication poses some new challenges.
Perhaps the key such challenge being the need to authenticate multimedia content as opposed to its representation. In this paper, we review some of the techniques proposed in the literature for multimedia content authentication. We then propose distortion bounded authentication techniques that give hard guarantees on the amount of distortion that will be tolerated before the multimedia object under consideration is deemed unauthentic. The basic idea behind distortion-bounded authentication is simple. Quantization is performed in feature space before authentication, thereby restricting image features in a known and deterministic manner.
The same quantization is performed prior to verification. Distortions less than half the quantization step size will not affect the verification process and the content will be deemed authentic. The basic framework is simple and can be applied with many different techniques, distortion measures and feature sets.
We give examples of distortion-bound authentication techniques using the L1 and L2 norms in pixel domain. A variety of robust non-perceptual watermarking methods have been proposed to solve the illegal copying and proof of ownership problems. Although a number of broad claims have been made in the field of robustness of various digital watermarking methods.
It is still difficult to handle combined or non-linear geometric transformations. In this paper we propose the SSP approach. We use a correlation based watermark pattern approach in the spatial domain which operates on image inherent properties when selecting the marking positions: self spanning patterns SSP. Each watermark pattern which represents one information bit of the whole watermark string is spanned over four image inherent properties like image edges or corners.
These four points specify a polygon over which the watermark pattern is spanned using a polygon filling algorithm. After transformations we search for our points based on the image characteristics. Then we span our pattern over the points and check if there was a one or a zero embedded. Continuing that for all pattern positions we can build the whole watermark string.
The advantage of the SSPs is that transformations need not be recognized, the marking positions and our pattern shape can be automatically found. Robust frame-dependent video watermarking Author s : Matthew J. Holliman; William W.
Macy; Minerva M. In this paper, we describe some of the problems associated with watermarking key management, with particular attention to the case of video. We also describe a possible solution to the problem, which is that of image-dependent watermarking, and briefly discuss some of the possible advantages to be gained from adopting such an approach. The paper also presents a simple, efficient means of robustly extracting bits from a video sequence. The algorithm has applications to secure, oblivious video watermark detection. We give a list of performance optimization guidelines and demonstrate some examples by optimizing our video watermark detection scheme.
In many applications, watermarking technology must have 1 the ability to be implemented at low cost, 2 robustness against common image processing operations, and 3 resilience against purely malicious attacks. Many works, including ours, have demonstrated watermark robustness and invisibility. This work demonstrates that, after some performance optimizations, we can decode a X MPEG-2 video and detect the watermarks, both in software, and display the decoded video frames in real-time on an Intel Pentium R III MHz system. Currently, there is only This paper presents an adaptive video watermarking using motion information.
Because video data have one more dimension than image data, simple adaptation of image watermarking method to video data would reveal some types of visual artifact such as flickering. In the proposed scheme, same watermark information is embedded for same region in each frame to decrease such visual artifact.
For higher robustness and invisibility, watermarking strength is adjusted by motion information and region complexity. Knox Show Abstract. Invisible watermark images can be incorporated in printed halftone images using specially designed halftone screens. The watermark information is embedded into the image by varying the spatial correlation of the halftone texture.
The halftone screen with embedded watermarks can be used exactly as a normal halftone screen, so there is no additional image processing required for processing individual images to embed watermarks. Once the binary output image is printed on the paper, the correlation of the binary image is converted into physical spatial correlation between neighboring areas of the printed image. This correlation relation is not visible to the eye but it can be detected by scanning the printed image on a desktop scanner and processing the scanned image.
Printer and scanner distortions can interfere with the self-alignment of the scanned image, so localized adjustments are made to detect the embedded spatial correlation information in the watermarked image. The retrieval of this watermark is robust to copying and distortion and it can be detected in reproductions of the halftone image.
With the ease of distribution of digital images, there is a growing concern for copyright control and authentication. While there are many existing watermarking and data hiding methods for natural images, almost none can be applied to halftone images. In this paper, we proposed two novel data hiding methods for halftone images.
It is found to be very effective for halftone images with relatively coarse textures. For halftone images with fine textures such as error diffusion with Steinberg kernel , the proposed Data Hiding Error Diffusion DHED gives significantly better visual quality by integrating the data hiding into the error diffusion operation. Both algorithms yield halftone images with good visual quality. JPEG is a common image format in the WWW and can potentially be used to hide data for secure internet communication and watermark for copyright control.
In this paper, we propose an algorithm to embed the secret or watermark information.
- Crosslinked and Thermally Treated Ultra-High Molecular Weight Polyethylene for Joint Replacements (ASTM Special Technical Publication, 1445)?
- How To Live In The Present Moment, Version 2.0 - Let Go Of The Past & Stop Worrying About The Future!
- Text, Speech and Dialogue: 13th International Conference, TSD 2010, Brno, Czech Republic, September 6-10, 2010. Proceedings.
- US8588462B1 - Video watermarking with fast detection - Google Patents;
- What Made Freud Laugh: An Attachment Perspective on Laughter.
We observe that it is perceptually undetectable if the DC coefficients in certain texture-rich blocks are modified by a small amount.