Tirtha Sankar Das

Coded Fingerprinting Based Watermarking to Resist Collusion Attacks and Trace Colluders

The alteration, repackaging, and redistribution of multimedia content like image, video, audio, etc. poses a serious threat to both national security and commercial markets. Presently with the growing popularity of digital media the world is becoming smaller and smaller. That is mainly due to the internet connectivity and WWW phenomena. But the copyright protection of intellectual properties has become a necessity for prevention of illegal copying and verification of content integrity. Here wavelet transform plays the role of an efficient and robust tool due to its multi-resolution capability along with singular value decomposition (SVD) for watermarking. Both of these when implemented with coded fingerprinting not only resist collusion attacks but can also help tracing colluders. This work here by focuses implementation of a hybrid watermarking scheme using SVD and wavelet transform along with coded fingerprinting developed for protection of the intellectual property.

SVD and Error Control Coding Based Digital Image Watermarking

Digital media is a craze these days. With the present day internet connectivity the world has become smaller. The copyright protections of intellectual properties have become a necessity for prevention of illegal copying and content integrity verification. Newer data hiding techniques that satisfy the requirements of imperceptibility, robustness, capacity, or data hiding rate and security of the hidden data etc. are being developed. Therefore the preference to go for digital image watermarking, to show resiliency against various unintentional or deliberate attacks has increased. Watermarking is a method of data authentication by embedding a watermark in image characteristics with expectation. Here in this work, this is done using a mathematical tool called the singular value decomposition (SVD). Earlier SVD had been used individually, as a tool for watermarking of digital media, but this work incorporates error control coding to it, by a novel zig-zag scan operation on pixels done before coding, thereby increasing the robustness. This work here by focuses on using both of them together to provide a robust technique developed for protection of the intellectual property against the popular malicious attacks. The algorithm is later applied and tested on the standard checkmark techniques practically by attacking the watermarked image against standard simulated attacks and recovering the watermarked logo from it.

DWT and SVD based image watermarking scheme using noise visibility and contrast sensitivity

This paper presents a robust and imperceptible methodology of watermark embedding in the transform domain using Discrete Wavelet Transform (DWT). The robustness is brought about by hiding the watermark in the Eigen values after computing the Singular Value Decomposition (SVD) on low frequency sub-band after DWT. While for the imperceptibility the Contrast Sensitivity Function (CSF) has been employed here along with the Noise Visibility Function (NVF). Human beings are sensitive to visual contrasts so CSF is used to take care of that while NVF characterizes the local image properties of texture, edge and smoothness to determine the optimal watermark locations and strength at the wavelet sub-bands for watermark embedding. The algorithm has been tested on 16 metrics out of which 10 are for imperceptibility and 6 for robustness for some popular attacks and the result has been found encouraging.

FPGA prototype of visual information hiding

The current explosion of digital media creates threats towards the security in multimedia data broadcasting. Watermarking technique becomes a prospective solution to this coercion by means of Intellectual Property Right Protection, Authentication and Integrity Verification of digital media. In this paper we introduce an approach that enables us to develop a low power, real time, reliable and secure data hiding system. As an effort towards the power efficient system, here we present an oblivious, spatial domain watermarking based authentication algorithm and its FPGA implementation. The low cost data embedding algorithm can hide watermark into original cover image coming from a sensor much faster than software implementation and the embedded image is easily transmitted to PC by using appropriate interface.

Hybrid image watermarking scheme using SVD and PDFB based contourlet transform

Copyright protection of intellectual property is a very large and growing business. This is due to the easier availability of all multimedia data with just a click of a mouse, resulting to the increase of piracy. Watermarking is one of the popular methods of authentication to help protect intellectual property rights. Of the various forms of multimedia data image is one of the most popular variant. Here a method of digital image watermarking is presented using singular value decomposition (SVD) which one of the very popular mathematical computation tools. Along with it a lot of transforms have been used earlier like discrete wavelet transform (DWT), DCT, Fourier transform, etc. to provide hybrid techniques. But here an unconventional transform introduced in the middle of this decade, called contourlet transform (CT) has been used. This transform being similar to DWT fits well to provide a robust watermarking scheme along with the SVD. Here the combination of pyramidal and directional filter bank (PDFB) in CT has been used.

On the implementation of a information hiding design based on saliency map

In this paper, an adaptive spatial domain image watermarking scheme is proposed which embeds watermark information to the uneven bit depth salient image pixels. Watermarked image thus produced has better visual transparency with respect to human visual system (HVS) with high payload capacity. In proposed scheme, salient pixels are determined using the bottom-up Graph-Based Visual Saliency (GBVS) model. Experimental results reveal that proposed scheme has less perceptual error as well as improved robustness than existing spatial domain embedding scheme.