Data Hiding Methods for Digital Image Security

Abstract

The main objective of this thesis is to study various challenges related to image security and propose methods to resolve them. This thesis is mainly focused to study in the areas of digital image watermarking techniques for copyright protection and data authentication, data hiding methods for secret message communication in the digital image communication and image encryption to provide confidentiality. newlineRobust watermarking scheme for copyright protection of digital images newlineTwo watermarking methods are proposed for the purpose of copyright protection. In the first method, the watermark image has been compressed using principal component analysis (PCA), and the compressed watermark information has been embedded into original image through singular value decomposition (SVD) watermarking scheme. In the second method, a set of stable speeded up robust feature keypoints (SURF) has been identified from original image, and a new histogram shifting technique has been introduced to embed the watermark bits in the circular region around the selected keypoints. newlineWatermarking scheme for surveillance video authentication newlineA video watermarking scheme has been proposed for the purpose of surveillance video authentication. In this scheme, a new scene change detection algorithm based on the combined measure of weighted block based mean absolute frame differences and count of edge pixels has been introduced for the fast detection of scene changes in the video. From the selected keyframes, the discrete cosine transform (DCT) coefficients of the blocks with higher entropy has been used to generate the watermark bits. The generated watermark bits have been embedded into low entropy regions with a new pixel swapping scheme based on the watermarking key.