IJSRSET162643 | Received: 18 Nov-2016 | Accepted: 24 Nov-2016 | November-December-2016 [(2) 6: 149-154] © 2016 IJSRSET | Volume 2 | Issue 6 | Print ISSN: 2395-1990 | Online ISSN : 2394-4099 Themed Section: Engineering and Technology 149 Enhancing Robustness of Embedded Medical Images with a 4 level Contourlet Transform J. Samuel Manoharan, G. Jayaseelan, P. Muralidharan Bharathiyar College of Engineering and Technology, Karaikal, UT, Thiruvettakudy, Puducherry, Tamil Nadu, India ABSTRACT Medical Images are an important class in the sense that they deal with real time conditions and are highly sensitive. Any slightest modification or manipulations done during their processing could degrade the quality of the image which could severely affect the efficiency of embedding techniques. Hence, Robustness and Fidelity are two important criteria that need to be adhered to in any data embedding technique. A multi resolution approximation technique using the Contourlet transform has been introduced in this paper and its effectiveness towards a wide range of aggressive image processing operations simulating the real time attacks has been found to make it a suitable transform to embed data into sensitiveness prone medical images. The results have been expressed in terms of well-known metrics like PSNR, Correlation Coefficient and the structural similarity index. Keywords : Data Embedding, Multi resolution approximation, Robustness, Attacks, Image Quality. I. INTRODUCTION Data Hiding is an age-old technique, which deals with concealing a data, which may be a audio, video or image, known as the watermark or payload, inside another data which may be a audio or video or image known as the Cover data. It might find various real time applications such as copyright protection, broadcast monitoring, tamper detection and covert communication [1]. Data embedding could be done in the spatial domain with pixel wise modifications or frequency domain using coefficient wise modifications with each having their own merits and demerits. Normally, a frequency domain technique is preferred if preserving of image quality is of concern. Three criteria govern the success of any embedding technique namely, robustness, perceptual imperceptibility and embedding capacity. Robustness denotes the capability of the embedded data to withstand intentional and unintentional attacks while perceptual invisibility denotes the degree of invisibility, of any modification made to the cover data, to the human eye. Embedding capacity measures the amount of payload that could be packed into the cover data without causing any degradation to the embedded data. All three mutually exist and are interrelated and hence a proper balance is highly essential to preserve the efficiency of the embedding technique. A general embedding and extraction scheme is shown in figure 1. A recent trend is the utilization of data embedding techniques for storing medical data which may be a diagnosis report of the patient into a medical image belonging to the patient itself [2] to serve the purpose of tele based medical services, labeling and archival, data base storage for later retrieval and hospital patient record management systems. Figure 1: A General data embedding and extraction scheme