detecting and recovering the tampered digital image using the source channel coding algorithm
D.Suma,N.Swathilakshmi,S.Prakash
Published in International Journal of Advanced Research in Computer Science Engineering and Information Technology
ISSN: 2321-3337 Impact Factor:1.521 Volume:4 Issue:3 Year: 01 April,2016 Pages:845-850
Abstract
Source channel coding algorithms have been widely applied to the field of image forensics recently. One of these very forensic applications is the protection of images against tampering. For this purpose, we need to design a Source channel coding algorithm fulfilling two purposes in case of image tampering: 1) detecting the tampered area of the received image and 2) recovering the lost information in the tampered zones. State-of-the-art techniques accomplish these tasks using watermarks consisting of check bits and reference bits. Check bits are used for tampering detection, whereas reference bits carry information about the whole image. The problem of recovering the lost reference bits still stands. This paper is aimed at showing that having the tampering location known, image tampering can be modeled and dealt with as an erasure error. Therefore, an appropriate design of channel code can protect the reference bits against tampering. In the present proposed method, the total bit is dedicated to three groups: 1) source encoder output bits; 2) channel code parity bits; and 3) check bits. In embedding phase, the original image is source coded and the output bit stream is protected using appropriate channel encoder. For image recovery, erasure locations detected by check bits help channel erasure decoder to retrieve the original source encoded image. Experimental results show that our proposed scheme significantly outperforms recent techniques in terms of image quality for both detected and recovered image. The image quality gain is achieved through spending less bit while image recovery quality is considerably improved as a consequence of consistent performance of designed source and channel codes.
Kewords
Tampering, Imageprotection, Selfrecovery, Detection, DWT algorithm, WaterMakering
Reference
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