International Journal of Scientific and Research Publications
Title: A MONOGRAPH ON WATERMARKING OF IMAGE USING ROBUST HISTOGRAM SHAPE METHOD
Author/s: Mrs. Swati Nitanaware, Apoorva B. Sharma
With the fast growth of communication networks and advances in multimedia processing technologies, multimedia protection has become a serious problem and rapid development of modern communication networks, information is transmitted with speeds never seen before. At the same time, illegally manipulated copies of digital media can be easily transmitted and distributed. As a result, copyright protection has become a major issue worldwide. Digital watermarking is a promising technique to tackle this problem. While digital watermarking can be applied to audio, image and video we focuses on image watermarking. A good image-watermarking method should be imperceptible, robust, and secure. Imperceptibility means that watermarks should be perceptually unobtrusive. Robustness indicates the ability of correctly extracting watermarks after undergoing different kinds of attacks. There are two types of attacks, which are signal processing attacks (e.g., compression, filtering, and noise addition) and geometric attacks (e.g., scaling, rotation, shearing, cropping, and random bending). Security refers to the resistance to unauthorized watermark decoding without knowing the secret key. Over the last decade, various image- watermarking methods have been developed. Many of these methods are robust to common signal processing attacks but do not cope well with geometric attacks. For example, some methods are resistant to median filtering and JPEG compression but very sensitive to rotation. To tackle geometric attacks, various techniques have been utilized in image watermarking.
Those techniques can be broadly classified into nonblind and blind watermarking techniques,
respectively. The nonblind watermarking techniques need to use the host image for watermark extraction at the decoding end. Thus, their practical usage is very limited. On the other hand, the blind watermarking techniques do not require the information of the host image in the decoder, which makes them more suitable for real-world applications. One of the blind method is exhaustive search which is carried out at the decoding end to search the embedded watermarks from the received image. The exhaustive search-based methods are very expensive in computation. Moreover, their false detection probability is high. Median filtering and JPEG compressions were overcame by Multiscale Gradient Direction Quantization method.