A more secure transmission of medical images by two label DWT and SVD based watermarking technique

Abstract

Digital multimedia content safety has progressively become an important issue. Digital watermarking is used to copyright protection. Any digital object can be used as a carrier to transmit information. If the info is related to object then it is known as a watermark which can be invisible or visible. The exchanging of digital content such as images is rapidly growing on computer networks. Safety and security of digital data, particularly in medical images, becomes important for many causes such as confidentiality, integrity and authentication. Presently, the most appropriate method for the exchange of medical images rest in cryptography but, once decrypted, the image is no longer protected and can be copied, duplicated, distributed and falsified simply. In the world of digital information, there are multiple danger zones like integrity damages and copyright, of digital object. In case of any dispute during rights violation, content maker can demonstrate his ownership by recovering the watermark. This way, digital watermarking has speedily appeared as a new advanced technology to boost the security of digital images. Actually, the inclusion of a watermark in a medical image can validate it and guarantee its reliability. The watermark should be unremarkably hidden does not affect the feature of the medical image. Two most important prerequisites for an efficient watermarking technique are robustness and security. Watermark must be robust and recoverable even if a part of content is altered by one or more attacks like resizing, compression, filtering, geometric distortions, etc. Due to its rising popularity, the Discrete Wavelet Transform is commonly used in recent watermarking techniques. In our work first we encrypt the watermark image using a random key after that In a Discrete Wavelet Transform based technique, the DWT coefficients are altered with the data that delineate the watermark. In this article, we present a combined two label DWT and Singular Value Decomposition (SVD) based technique. After decomposing the cover digital image into four bands LL, LH, HL, and HH where LL represents the coarse level coefficient which is the low frequency part of the image and LH, HL, and HH denote the finest scale wavelet coefficient, we tend to apply the SVD to each band, and insert the same watermark data via renovating the singular values. Alteration in all frequencies permits the development of a watermarking technique that is robust to various attacks.