An overview of encryption algorithms in color images

An enhanced hybrid image watermarking scheme for security of medical and non-medical images based on DWT and 2-D SVD

Nowadays secure medical image watermarking had become a stringent task in telemedicine. This paper presents a novel medical image watermarking method by fuzzy based Region of Interest (ROI) selection and wavelet transformation approach to embed encrypted watermark. First, the source image will undergo fuzzification to determine the critical points through central and final intensity along the radial line for selecting region of interest (ROI). Second, watermark image is altered to time-frequency domain through wavelet decomposition where the sub-bands are swapped based on the magnitude value obtained through logistic mapping. In the each sub-band all the pixels get swapped, results in fully encrypted image which guarantees the watermark to a secure, reliable and an unbreakable form. In order to provide more robustness to watermark image, singular values are obtained for encrypted watermark image and key component is calculated for avoiding false positive error. Singular values of the source and watermark image are modified through key component. Experimental results reveal that the proposed algorithm attains high robustness and improved security to the watermarked image against various kinds of attacks.

A fuzzy based ROI selection for encryption and watermarking in medical image using DWT and SVD

In this paper, a robust blind image watermarking method is proposed for copyright protection of digital images. This hybrid method relies on combining two well-known transforms that are the discrete Fourier transform (DFT) and the discrete cosine transform (DCT). The motivation behind this combination is to enhance the imperceptibility and the robustness. The imperceptibility requirement is achieved by using magnitudes of DFT coefficients while the robustness improvement is ensured by applying DCT to the DFT coefficients magnitude. The watermark is embedded by modifying the coefficients of the middle band of the DCT using a secret key. The security of the proposed method is enhanced by applying Arnold transform (AT) to the watermark before embedding. Experiments were conducted on natural and textured images. Results show that, compared with state-of-the-art methods, the proposed method is robust to a wide range of attacks while preserving high imperceptibility.

Hybrid blind robust image watermarking technique based on DFT-DCT and Arnold transform

DCT & DWT based watermarking scheme for medical information security

An evolutionary programming approach for securing medical images using watermarking scheme in invariant discrete wavelet transformation

In this paper, we present the concept of Moment Invariants. Objects can be detected with the help of Moment Invariants. Different Moment Invariants are discussed in this paper. The pitfalls of Fourier-Mellin Invariants and Legendre Moment Invariants are discussed. Two Dimensional Moments of ��× �� images are sampled and proved that 2D Geometrical Moment Invariants are far better than the other Invariants in terms of the object detection. Index Terms—Image function, algebraic invariants, polar coordinates, affine groups, information redundancy, fourier-mellin invariants, legendre moment invariants, counter-based shape descriptors, geometric moment invariants.

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Detection and Comparison of Objects Using Two Dimensional Geometric Moment Invariants

Watermarking plays very important role in the present image processing scenario. Watermarking algorithms that depend on the inherent geometry of the image for synchronization fail due to desynchronization through geometric manipulations. A class of algorithms tries to overcome this problem using feature-based synchronization markers. These are essentially composed of three building blocks: feature point extraction, elementary patch formation and registration to a standard geometry, and watermarking of elementary patches. Extracted feature points are bound to the image content, thus may be used as robust synchronization markers. This set of points is used to divide the image into elementary patches, which are warped into a standard geometry ensuring the exact synchronization during insertion and extraction. Once the synchronization is provided, any watermarking technique may reliably operate on elementary patches.

/pdf/use-of-synchronized-markers-and-watermarking-techniques-for-31dl5ryq9f.pdf

Y. Gangadhar

Papers

An evolutionary programming approach for securing medical images using watermarking scheme in invariant discrete wavelet transformation

Detection and Comparison of Objects Using Two Dimensional Geometric Moment Invariants

Use of synchronized markers and watermarking techniques for Geometric manipulations of images