European Journal of Applied Sciences 9 (1): 27-36, 2017 ISSN 2079-2077 © IDOSI Publications, 2017 DOI: 10.5829/idosi.ejas.2017.27.36 Corresponding Author: C. Kanmani Pappa, Department of ECE, National College of Engineering, Maruthakulam-627151, Tamilnadu, India. 27 Robust Reversible Watermarking Based on Normalized Correlation Combined with Cdma Techniques M. Subbulakshmi, M. Vijayaraj and C. Kanmani Pappa 1 2 1 Department of ECE, National College of Engineering, 1 Maruthakulam-627151, Tamilnadu, India Department of ECE, Government College of Engineering, 2 Tirunelveli -627007, Tamilnadu, India Abstract: In this paper, the Normalized Correlation based Quantization Index Modulation (NCQIM), Least Significant Bit (LSB) and Code Division Multiple Access (CDMA) techniques are combined for reversible watermarking. By using this method, the normalized correlation is calculated between the host signal and a random signal. Then the modulation is performed on generated normalized correlation by using codeword from the codebook associated with the embedded information. The codebooks are designed by using uniform quantizer for modulation. Then the LSB method is used. In this method, the LSB values of each pixel in the image are modified. Then CDMA technique is applied. Then watermark embedding is done through the above performed modulation. This watermark signal is used to produce minimum distortion in valumetric scaling and additive noise attacks. At decoder side, the watermark is extracted using the technique which is done at embedder side. The proposed method is simulated on different images and the watermark imperceptibility is achieved by using the parameter Peak Signal to Noise Ratio (PSNR). The robustness is increased by reducing Bit Error Rate (BER). This proposed technique achieves high embedding capacity in high noise environment, high robustness when compared to conventional Quantization Index Modulation (QIM) methods. Key words: Bit Error Rate Imperceptibility Mean Square Error Normalized correlation Peak Signal to Noise Ratio Uniform Quantizer INTRODUCTION In addition to copyright protection, watermarking has In the current trends of the world, due to the recent control, broadcast technology, communication lines. One advancement, most of the individuals prefer to use the of the most important technique proposed is Quantization internet as the primary medium to transfer data from one Index Modulation (QIM), where watermark embedding is region to another region across the whole world. The data obtained by quantizing the host or input signal with a transmission is made very simple, fast and accurate using quantizer level chosen among a full set of quantizers that the net facility. However, security is the main issue while are each associated with a different message. The basic sending data over the internet. The private content can be implementation method of QIM, is known as Dither hacked in various ways. Therefore it becomes required to Modulation (DM), adopts a large set of scalar and uniform take data security into consideration. Data security means quantizes. Later, the distortion compensation method was protection or safeguard of data from unauthorized users combined with the QIM method, resulting in the or hackers and providing high security to prevent data Distortion Compensated QIM (DC-QIM). DC-QIM follows alteration. In order to overcome the problem of the Costa’s procedures and closes the gap to capacity. security attacks in data transfers over the internet, digital The Scalar Costa Scheme (SCS) proposed in can be image watermarking technique is used. It is one of the regarded as a special example of DC-QIM. The theoretical prominent methods to fulfill the gap between copyright presentation of QIM methods has been extensively issues and digital distribution of data content. investigated. In these basic type algorithms, the amplitude many other applications, including authentication, access