Multicarrier spread spectrum watermarking for secure error concealment in fading channel

Abstract

This paper proposes a novel multicarrier spread spectrum (SS) watermarking scheme for the application of image error concealment using multicarrier-code division multiple access (MC-CDMA) with binary phase shift keying (BPSK) transmission in Rayleigh fading channel. The goal is achieved by embedding important information (image digest) which is extracted from the original image itself, and is used to introduce sufficient redundancy in the transmitted image. Half-toning technique is applied to obtain image digest from its low-resolution version. At the decoder side, data demodulation as well as watermark decoding are done using minimum mean square error combining (MM-SEC) strategy. The extracted image digest is used to correct the damaged regions. The integration of SS watermarking with the existing SS modulation not only simplifies the design but also offers significant performance improvement for error concealment in fading channel. Authorized users having the knowledge of code patterns for SS watermarking can only perform the error concealment operation and the method is secured. Experimental results duly support the effectiveness of the proposed scheme.

Optimal watermark embedding combining spread spectrum and quantization

“…The quantization watermarking obtains null host signal interference and achieves a significant gain in terms of watermark capacity over SS watermarking. However, it suffers from serious disadvantages like extreme sensitivity to valumetric scaling [16] and fading operation [17].…”

Spread Spectrum Watermarking: Principles and Applications in Fading Channel

“…To the best of our knowledge, its importance was first highlighted in (Kundur & Hatzinakos, www.intechopen.com 2001) where the authors hypothesize that many common multimedia signal distortions, including cropping, filtering, and perceptual coding, are not accurately modeled as narrow band interference. During recent times, watermarking finds typical application in error concealment for image and video transmission through radio mobile fading channel (Maity et al 2010). Moreover, for image signals, fading or gain-like attack operation may occur during the scanning process where light is not distributed uniformly over the paper.…”

“…The integration of OFDM with CDMA, in the form of MC-CDMA, is also developed in high payload watermarking for collusion resilient fingerprinting (Cha & Kuo, 2009) and error concealment in time-varying channel (Maity et al 2010). To this aim, estimation for such attack gains is done using GA.…”

Performance analysis of data transmission in MC-CDMA radio interface with turbo codes

“…In MC-CDMA we can apply spreading sequences in the frequency domain, mapping a different chip of a spreading sequence to an individual OFDM subcarrier [7,10,12]. The signals of MC-CDMA can be easily transmitted and received using the fast Fourier transform (FFT) device without increasing the transmitter and receiver complexities.…”