Multiple Watermarking pada Citra Medis pada Domain Wavelet Menggunakan BCH Encoding

ABSTRAKSI: Citra medis digital mempunyai dua hal penting yang perlu diperhatikan yaitu autentikasi kepemilikan dan keaslian citra. Kepemilikan citra harus dinyatakan dengan benar dan modifikasi pada citra harus dapat dideteksi. Solusi dari kedua permasalahan tersebut adalah dengan multiple watermarking. Pada Tugas Akhir ini multiple watermark terdiri dari dua jenis yaitu signature watermark dan reference watermark. Signature Watermark berupa teks, digunakan untuk menyatakan kepemilikan dari citra medis. Sedangkan reference watermark berupa citra, digunakan untuk mendeteksi modifikasi yang mungkin terjadi pada citra medis digital. Penyisipan kedua watermark dilakukan pada domain wavelet dengan melakukan dekomposisi 2 level dan kuantisasi pada koefisien transformasi. Sesuai dengan adanya batasan yang tegas yang diterapkan pada citra medis, pada proses penyisipannya dimungkinkan melakukan pendefinisian terhadap Region of Interest (ROI) yang mana nilai diagnostiknya dilindungi karena informasi yang disisipkan disana hanya bertujuan untuk integrity control. Selain itu, untuk meningkatkan ketahanan dari signature watermark digunakanlah hybrid coding, yaitu penyisipan BCH encoded watermarks secara berulang. Pengujian dilakukan dengan mensimulasikan sejumlah serangan terhadap citra yaitu sharpening, white Gaussian noise dan kompresi JPEG. Yang akan dianalisis adalah kualitas citra terwatermark dan ketahanan teks signature serta kerentanan citra reference. Hasil pengujian antara lain teknik multiple watermarking menunjukan kinerja imperceptibility yang baik. Sharpening merupakan serangan yang keras dan penggunaan hybrid coding tidak mampu meningkatkan ketahanan signature watermark terhadap serangan ini. Sedangkan untuk pemberian noise dan kompresi JPEG, penggunaan hybrid coding menunjukan performa yang baik dengan peningkatan robustness setelah level serangan mencapai tingkat tertentu. Sementara itu, reference watermark memiliki tingkat fragilitas yang tinggi dan mampu mendeteksi serangan yang terjadi bahkan untuk level serangan terkecil sekalipun.Kata Kunci : multiple watermarking, wavelet decomposition, repetitive BCH encodingABSTRACT: Medical image in digital form has two major thing, they are origin authentication and integrity control. The ownership of medical image must be known correctly and the tampering of image must be detected. The solution from that problems is multiple watermarking. In this final project, the multiple watermark consists of signature watermark and reference watermark. Signature watermark is a text which defines the ownership of medical image. Whereas, reference watermark is an image which can detect possibly tampering on medical digital image.The multiple watermarks are embedded in a wavelet domain by doing decomposition 2 levels and applying a proper quantization of coefficients. In accordance with strict limitations applying to medical images, the scheme allows the definition of a region of interest (ROI) whose diagnostic value is protected since the only additional information embedded therein aims at integrity control. The robustness of signature watermark is enhanced through a form of hybrid coding, which includes repetitive embedding of BCH encoded watermarks. The testing has done by giving some attack to watermarked image that is sharpening, white Gaussian noise and JPEG compression. Which will be analysis is quality of watermarked image, robustness of signature text watermark and fragility of reference image watermark. The result of the testing are multiple watermarking technique shows good performance in term of imperceptibility. Sharpening is hard attack where using hybrid coding incapable enhance robustness of signature watermark toward this attack. For noise and JPEG compression, using hybrid coding show good performance through robustness enhancement after attack level reach certain degree. Meanwhile the reference watermark has high fragility and capable to detect the tampering although that tampering is very small.Keyword: multiple watermarking, wavelet decomposition, repetitive BCH encodin

Spread spectrum-based video watermarking algorithms for copyright protection

Merged with duplicate record 10026.1/2263 on 14.03.2017 by CS (TIS)Digital technologies know an unprecedented expansion in the last years. The consumer can now benefit from hardware and software which was considered state-of-the-art several years ago. The advantages offered by the digital technologies are major but the same digital technology opens the door for unlimited piracy. Copying an analogue VCR tape was certainly possible and relatively easy, in spite of various forms of protection, but due to the analogue environment, the subsequent copies had an inherent loss in quality. This was a natural way of limiting the multiple copying of a video material. With digital technology, this barrier disappears, being possible to make as many copies as desired, without any loss in quality whatsoever. Digital watermarking is one of the best available tools for fighting this threat. The aim of the present work was to develop a digital watermarking system compliant with the recommendations drawn by the EBU, for video broadcast monitoring. Since the watermark can be inserted in either spatial domain or transform domain, this aspect was investigated and led to the conclusion that wavelet transform is one of the best solutions available. Since watermarking is not an easy task, especially considering the robustness under various attacks several techniques were employed in order to increase the capacity/robustness of the system: spread-spectrum and modulation techniques to cast the watermark, powerful error correction to protect the mark, human visual models to insert a robust mark and to ensure its invisibility. The combination of these methods led to a major improvement, but yet the system wasn't robust to several important geometrical attacks. In order to achieve this last milestone, the system uses two distinct watermarks: a spatial domain reference watermark and the main watermark embedded in the wavelet domain. By using this reference watermark and techniques specific to image registration, the system is able to determine the parameters of the attack and revert it. Once the attack was reverted, the main watermark is recovered. The final result is a high capacity, blind DWr-based video watermarking system, robust to a wide range of attacks.BBC Research & Developmen

Authentication with Distortion Criteria

In a variety of applications, there is a need to authenticate content that has experienced legitimate editing in addition to potential tampering attacks. We develop one formulation of this problem based on a strict notion of security, and characterize and interpret the associated information-theoretic performance limits. The results can be viewed as a natural generalization of classical approaches to traditional authentication. Additional insights into the structure of such systems and their behavior are obtained by further specializing the results to Bernoulli and Gaussian cases. The associated systems are shown to be substantially better in terms of performance and/or security than commonly advocated approaches based on data hiding and digital watermarking. Finally, the formulation is extended to obtain efficient layered authentication system constructions.Comment: 22 pages, 10 figure

A contrast-sensitive reversible visible image watermarking technique

A reversible (also called lossless, distortion-free, or invertible) visible watermarking scheme is proposed to satisfy the applications, in which the visible watermark is expected to combat copyright piracy but can be removed to losslessly recover the original image. We transparently reveal the watermark image by overlapping it on a user-specified region of the host image through adaptively adjusting the pixel values beneath the watermark, depending on the human visual system-based scaling factors. In order to achieve reversibility, a reconstruction/ recovery packet, which is utilized to restore the watermarked area, is reversibly inserted into non-visibly-watermarked region. The packet is established according to the difference image between the original image and its approximate version instead of its visibly watermarked version so as to alleviate its overhead. For the generation of the approximation, we develop a simple prediction technique that makes use of the unaltered neighboring pixels as auxiliary information. The recovery packet is uniquely encoded before hiding so that the original watermark pattern can be reconstructed based on the encoded packet. In this way, the image recovery process is carried out without needing the availability of the watermark. In addition, our method adopts data compression for further reduction in the recovery packet size and improvement in embedding capacity. The experimental results demonstrate the superiority of the proposed scheme compared to the existing methods

Implementation of Transform Based Techniques in Digital Image Watermarking

Digital image watermarking is used to resolve the problems of data security and copyright protection. In many applications of digital watermarking, watermarked image of good quality are required. But here is a trade-off between number of embedded watermark images and quality of watermarked images. This aspect is quite important in case of multiple digital image watermarking. This project presents a robust digital image watermarking using discrete cosine transform (DCT) method. Compression on a watermarked image can significantly affect the detection of the embedded watermark. The detection of the presence or absence of a watermarked in an image is often affected if the watermarked image has undergone compression. Compression can also be considered as an attack on watermarked images. To show that a particular watermarking scheme is robust against compression, simulation is often relied DOI: 10.17762/ijritcc2321-8169.15084