Amplitude Scale Estimation for Quantization-Based Watermarking

Abstract

Abstract-In this paper we propose a maximum likelihood technique to combat amplitude scaling attacks within a quantizationbased watermarking context. We concentrate on operations that are common in many applications and at the same time devastating to this class of watermarking schemes, namely, amplitude scaling in combination with additive noise. First we derive the probability density function of the watermarked and attacked data in the absence of subtractive dither. Next we extend these models to incorporate subtractive dither in the encoder. The dither sequence is primarily used for security purposes, and the dither is assumed to be known also to the decoder. We design the dither signal statistics such that an attacker having no knowledge of the dither cannot decode the watermark. Using an approximation of the probability density function in the presence of subtractive dither, we derive a maximum likelihood procedure for estimating amplitude scaling factors. Experiments are performed with synthetic and real audio signals, showing the feasibility of the proposed approach under realistic conditions. Index Terms-Maximum likelihood estimation, probability of error, quantization, statistics, subtractive dither, watermarking.

Image Watermarking in Higher-Order Gradient Domain

“…• The third type of methods estimate the scaling factor based on the structure of the received data (Eggers, Bäuml & Girod, 2002;Lagendijk & Shterev, 2004;Shterev & Lagendijk, 2006). • The fourth type of methods embed the watermark in the gain-invariant domains (Ourique et al, 2005;Perez-Gonzalez et al, 2005).…”

Spread Transform Dither Modulation using a Perceptual Model

“…A number of algorithms have recently been proposed to counter this [3]- [8], specifically rational dither modulation (RDM) [4], adaptive QIM using a modified Watson distance (QIM-MW) [5] and adaptive RDM using a modified Watson distance (RDM-MW) [7]. These latter methods are based on adaptively changing the quantization step size.…”

“…The problem of valumetric scaling has received widespread attention and a number of solutions have been proposed [3]- [8]. In contrast, there has been only limited research focused on the issue of re-quantization, among which JPEG compression is a typical one.…”

Difference angle quantization index modulation scheme for image watermarking

“…In recent years, many schemes such as the use of pilot signals [5][6][7], the design of amplitude scale invariant codes [8][9][10]16] and the AQIM method [1,13] have been proposed to tackle this problem. Among all the above mentioned methods, the AQIM method [1] is the most simple and effective watermarking scheme that can resist the gain Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/image attacks.…”