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One of the foremost requisite for human perception and computer vision task is to get an image with all objects in focus. The image fusion process, as one of the solutions, allows getting a clear fused image from several images acquired with different focus levels of a scene. In this paper, a novel framework for multi-focus image fusion is proposed, which is computationally simple since it realizes only in the spatial domain. The proposed framework is based on the fractal dimensions of the images into the fusion process. The extensive experiments on different multi-focus image sets demonstrate that it is consistently superior to the conventional image fusion methods in terms of visual and quantitative evaluations. © 2013 IEEE.

Department of Mathematics

World University root node

2013 4th National Conference on Computer Vision, Pattern Recognition, Image Processing and Graphics, NCVPRIPG 2013

A novel framework for multi-focus image fusion

Generally, in watermarking scheme the size of the watermark is very small when compare to host image. On the contrary, this is an attempt in which a new watermarking scheme is presented where the size of host image is very small when compare with watermark image. The core idea of the proposed scheme is to scale up the size of host image equal to the size of watermark via over-sampling and then decompose it using stationary wavelet transform. A gray scale watermark is embedded in the low frequency sub-band at the finest level using singular value decomposition. To prevent ambiguity and enhance the security, a binary watermark is also embedded in loss-less manner. Finally, a reliable watermark extraction scheme is developed for extracting both the watermarks. The experimental results demonstrate better visual imperceptibility and resiliency of the proposed scheme against intentional or un-intentional variety of attacks. © 2011 Springer Science+Business Media, LLC.

Multimedia Tools and Applications

A new aspect in robust digital watermarking

Multimodal medical image fusion, as a powerful tool for the clinical applications, has developed with the advent of various imaging modalities in medical imaging. The main motivation is to capture most relevant information from sources into a single output, which plays an important role in medical diagnosis. In this paper, a novel fusion framework is proposed for multimodal medical images based on non-subsampled contourlet transform (NSCT). The source medical images are first transformed by NSCT followed by combining low- and high-frequency components. Two different fusion rules based on phase congruency and directive contrast are proposed and used to fuse low- and high-frequency coefficients. Finally, the fused image is constructed by the inverse NSCT with all composite coefficients. Experimental results and comparative study show that the proposed fusion framework provides an effective way to enable more accurate analysis of multimodality images. Further, the applicability of the proposed framework is carried out by the three clinical examples of persons affected with Alzheimer, subacute stroke and recurrent tumor. © 1999-2012 IEEE.

IEEE Transactions on Multimedia

Directive contrast based multimodal medical image fusion in NSCT domain

In this article, a novel logo watermarking scheme is proposed based on wavelet frame transform, singular value decomposition and automatic thresholding. The proposed scheme essentially rectifies the ambiguity problem in the SVD-based watermarking. The core idea is to randomly upscale the size of host image using reversible random extension transform followed by the embedding of logo watermark in the wavelet frame domain. After embedding, a verification phase is casted with the help of a binary watermark and toral automorphism. At the extraction end, the binary watermark is first extracted followed by the verification of watermarked image. The logo watermark is extracted if and only if the watermarked image is verified. The security, attack and comparative analysis confirm high security, efficiency and robustness of the proposed watermarking system. © 2013 ACM.

ACM Transactions on Multimedia Computing, Communications and Applications

Secure randomized image watermarking based on singular value decomposition

Multi-modal medical image fusion, as a powerful tool for the clinical applications, has developed with the advent of various imaging modalities in medical imaging. The main motivation is to capture most relevant information from sources into a single output, which plays an important role in medical diagnosis. In this paper, a novel framework for medical image fusion based on framelet transform is proposed considering the characteristics of human visual system (HVS). The core idea behind the proposed framework is to decompose all source images by the framelet transform. Two different HVS inspired fusion rules are proposed for combining the low- and high-frequency coefficients respectively. The former is based on the visibility measure, and the latter is based on the texture information. Finally, the fused image is constructed by the inverse framelet transform with all composite coefficients. Experimental results highlight the expediency and suitability of the proposed framework. The efficiency of the proposed method is demonstrated by the different experiments on different multi-modal medical images. Further, the enhanced performance of the proposed framework is understood from the comparison with existing algorithms. © 2012 Elsevier Ltd. All rights reserved.

Expert Systems with Applications

Human visual system inspired multi-modal medical image fusion framework

Multifocus image fusion is the process of obtaining a single image from multiple partially focused images such that the newly formed image consists of the well-defined information extracted from each source image. This paper proposes the use of saliency of the source images based on Mutual Spectral Residual. Spectral Residual brings out the unique/salient features of an image in frequency domain. The idea of proposed mutual spectral residual is to emphasize the relative unique features of a source image with respect to the other source images. The relative unique features are utilized to form saliency maps for each source image. These saliency maps can clearly indicate the focused and defocused parts of an image. Based on the saliency maps obtained, the image fusion takes place in spatial domain. Visual inspection and quantitative evaluation of the fused images obtained by the proposed method, using different evaluation metrics, demonstrate its effectiveness over several existing image fusion methods. © 2013 Elsevier Inc. All rights reserved.

Digital Signal Processing: A Review Journal

Mutual spectral residual approach for multifocus image fusion

In this paper, a new watermarking scheme based on redundant fractional wavelet transform is presented. First, the definition and implementation of redundant fractional wavelet transform is proposed followed by its use in watermark embedding. For embedding, the gray-scale logo watermark is used and is embedded in the middle singular values of the redundant fractional wavelet domain. In order to enhance the security, a binary watermark is also embedded in the host image in lossless manner based on automatic thresholding. Finally, a reliable extraction process is developed for the extraction of both the watermarks from the possibly distorted image. The feasibility and robustness of the proposed technique is carried out by the security and attack analysis on different images. © 2013.

Fulltext

Mathematical and Computer Modelling

A new logo watermarking based on redundant fractional wavelet transform

The fractional wavelet transform is a useful mathematical transformation that generalizes the most prominent tool in signal and image processing namely wavelet transform by rotation of signals in the time-frequency plane. The definition of discrete fractional wavelet transform is not reported yet in the literature. Therefore, a definition of the discrete fractional wavelet transform is consolidated by discretizing continuous fractional wavelet transform in the proposed work. Possible applications of the transform are in transient signal processing, image analysis, image transmission, biometrics, image compression etc. In this paper, image transmission is chosen as the primary application and hence a novel encryption scheme is proposed for securing multiple images during communication and transmission over insecure channel. The proposed multiple image encryption scheme is consolidated by fractional wavelet transform and chaotic maps. First, all the images are encrypted followed by their sharing. The sharing process is done considering numerical techniques by making the sharing process a system of linear equations. Experimental results and security analysis demonstrate the efficiency and robustness of the proposed primary application. © 2012 Elsevier Inc. All rights reserved.

Information Sciences

Discrete fractional wavelet transform and its application to multiple encryption

In this paper, a novel biometrics inspired watermarking technique is proposed. For this purpose, a newly proposed mathematical transform, namely the fractional dual tree complex wavelet transform (FrDT-CWT), and singular value decomposition (SVD) are used. The core idea is to use biometrically generated keys in the embedding process of a gray-scale watermark. Therefore, this paper first proposes a method for generating keys from biometrics efficiently. The host image is first randomized by Hessenberg decomposition and a chaotic map, followed by embedding in the FrDT-CWT domain by modifying the singular values of the randomized image. Further, in order to prevent the ambiguity problem of SVD-based techniques, a verification step is introduced to verify the watermarked image. Finally, a reliable extraction process is proposed to extract the watermark from the possibly attacked watermarked image after verification. The security, attack, and comparative analysis confirms the high security, efficiency, and robustness of the proposed watermarking technique. © 2012 Elsevier B.V. All rights reserved.

Future Generation Computer Systems

Biometrics inspired watermarking based on a fractional dual tree complex wavelet transform

Joint watermarking and encryption is an upcoming security solution that combines leading but complementary techniques to achieve an enhanced security level. Real time applications using joint watermarking and encryption framework has three requirements: data to be efficiently compressed, watermarking technique to sustain compression, and encryption technique to be developed in a way so as not to disturb the compression efficiency. Finding an optimal solution that combines the three techniques while fulfilling these requirements is a challenging problem. This paper thus, proposes a wavelet domain based joint watermarking and encryption framework that employs singular value decomposition based watermark embedding and sign bit encryption prior to compression. The varying significance of different subbands has been considered to encrypt the data without adversely effecting the compression ratio. Experimental analysis using various evaluation parameters and attack scenarios has revealed the ability of the proposed framework to prove content-ownership, even from the encrypted data. Comparative analysis with the existing techniques reflect its ability to provide better security with less computational resources. This makes it a preferable solution for data security at all stages of data archival, transmission or distribution. © 2012 Springer Science+Business Media, LLC.

Joint watermarking and encryption for still visual data

In this paper, a security solution for stereo images during communication and transmission is proposed. For this purpose, a robust stereo-image coding algorithm via encryption technique is proposed using step space filling curve, non-linear chaotic map and singular value decomposition. The core idea is to first encrypt the left and right stereo images followed by the merging process of left and right stereo images into single image which further treated as final encrypted image. The final encrypted image is transmitted over the insecure channel. At the receiver end, left and right encrypted images are extracted from final encrypted image followed by the decryption process. The efficiency and the robustness of the proposed algorithm are demonstrated by different experiments and analysis on different stereo image pairs. © 2012 American Scientific Publishers All rights reserved.

Advanced Science Letters

Security of stereo images during communication and transmission

In this paper, a security solution during communication and transmission of fingerprint data is proposed in the form of a novel encryption technique based on reversible hidden transform (RHT) and fractional wavelet packet transform (FrWPT). The core idea of the proposed technique is to change the gray values in the spatial domain using RHT followed by the deformation of FrWPT coefficients by singular value decomposition and chaotic map. Hence, security solution relies on both spatial and frequency domains. Finally, a reliable decryption scheme is also presented to reconstruct the original fingerprint image from the encrypted image. Experimental results and security analysis demonstrate the efficiency and robustness of the proposed scheme. © 2012 IEEE.

IEEE Transactions on Instrumentation and Measurement

Chaos-based security solution for fingerprint data during communication and transmission

In this study, the concept of fractional wavelet packet transform is explored with its application in digital watermarking. The core idea of the proposed watermarking scheme is to decompose an image via fractional wavelet packet transform and then a reference image is created by changing the positions of all frequency sub-bands at each level with respect to some rule which is secret and only known to the owner/creator. For embedding, the reference image is segmented into non-overlapping blocks and modify its singular values with the watermark singular values. Finally, a reliable watermark extraction algorithm is developed for the extraction of watermark from the distorted image. The feasibility of this method and its robustness against different kind of attacks are verified by computer simulations. © 2012 The Institution of Engineering and Technology.

IET Image Processing

Robust watermarking using fractional wavelet packet transform

In this paper, the dual tree complex wavelet transform, which is an important tool and recent advancement in signal and image processing, has been generalized by coalescing dual tree complex wavelet transform and fractional Fourier transform. The new transform, i.e. the fractional dual tree complex wavelet transform (FrDT-CWT) inherits the excellent mathematical properties of dual tree complex wavelet transform and fractional Fourier transform. Possible applications of the proposed transform are in biometrics, image compression, image transmission, transient signal processing etc. In this paper, biometric is chosen as the primary application and hence a new technique is proposed for securing biometrics during communication and transmission over insecure channel. © 2010 Elsevier B.V. All rights reserved.

Fractional dual tree complex wavelet transform and its application to biometric security during communication and transmission

In this paper, a robust logo watermarking scheme based on image fusion is proposed. Unlike existing watermarking schemes, the used watermark is a gray scale logo instead of randomly generated Gaussian noise type watermark. The core idea of the proposed scheme is to decompose an image into frequency sub-bands using wavelet transform followed by the embedding in selected blocks of sub-bands obtained by ZIG-ZAG sequence. Block selection is done by taking variance of the blocks into consideration. The experimental results show better visual imperceptibility and resiliency of the proposed scheme against intentional or un-intentional variety of attacks and superiority is carried out by comparison made by us with the existing schemes. © 2012 Elsevier Ltd. All rights reserved.

Computers and Electrical Engineering

Robust gray-scale logo watermarking in wavelet domain

In this paper, a new encryption scheme with three different modes of operations is proposed based on dual space-filling curves (SFSs) and a fractional wavelet transform (FrWT). This scheme is initially proposed for images and then extended to videos. The core idea behind the proposed schemes is to decompose an image/video first by the FrWT followed by the shuffling of each sub-band coefficients by means of a dual SFC. At last, an inverse FrWT is performed to get the encrypted image/video. A reliable decryption process is also proposed to construct the original image from the encrypted image. The experimental results, security and comparative analysis demonstrate the efficiency and robustness of the proposed scheme. Further, this paper also proposes an efficient implementation of an FrWT based on chaotic maps. © 2011 The Author. Published by Oxford University Press on behalf of The British Computer Society. All rights reserved.

Computer Journal

Image and video encryption based on dual space-filling curves

In this paper, a novel image fusion algorithm based on framelet transform is presented. The core idea is to decompose all the images to be fused into low and high-frequency bands using framelet transform. For fusion, two different selection strategies are developed and used for low and high-frequency bands. The first strategy is adaptive weighted average based on local energy and is applied to fuse the low-frequency bands. In order to fuse high-frequency bands, a new strategy is developed based on texture while exploiting the human visual system characteristics, which can preserve more details in source images and further improve the quality of fused image. Experimental results demonstrate the efficiency and better performance than existing image fusion methods both in visual inspection and objective evaluation criteria. © 2012 World Scientific Publishing Company.

International Journal of Wavelets, Multiresolution and Information Processing

An image fusion framework based on human visual system in framelet domain

In this paper, a novel, yet simple, watermarking algorithm for image authentication is proposed using fractional wavelet packet transform (FRWPT) via singular value decomposition (SVD). Unlike the traditional watermarking schemes where the watermark is added to the transform coefficients, the proposed algorithm is based on embedding in the singular values (luminance) of the host image. To improve the fidelity, the perceptual quality of the watermarked image and to enhance the security of watermarking, we model an adjustable watermarking algorithm. The meaning of the word adjustable is that the watermark is embedded into the host image by taking two watermark embedding strengths, according to owner and some cryptographic conditions. Finally, a reliable watermark extraction algorithm is developed for the extraction of watermark from the distorted image. The feasibility of this method and its robustness against different kind of attacks are verified by computer simulations and comparison with the existing work. © 2011 Elsevier Ltd. All rights reserved.

Computers and Security

A new robust adjustable logo watermarking scheme

In this paper, an efficient yet simple selective encryption technique is proposed based on Saw-Tooth space filling curve, pixels of interest, non-linear chaotic map and singular value decomposition. The core idea of the proposed scheme is to scramble the pixel positions by the means of Saw-Tooth space filling curve followed by the selection of significant pixels using pixels of interest method. Then the diffusion process is done on the significant pixels using a secret image key obtained from non-linear chaotic map and singular value decomposition. Finally, a reliable decryption process is proposed to construct original image from the encrypted image. The analysis and experimental results show that the proposed scheme can achieve various purposes of selective encryption and is computationally secure. © 2012 Elsevier Inc. All rights reserved.

Selective image encryption based on pixels of interest and singular value decomposition

In this correspondence paper, the wavelet transform, which is an important tool in signal and image processing, has been generalized by coalescing wavelet transform and fractional random transform. The new transform, i.e., fractional random wavelet transform (FrRnWT) inherits the excellent mathematical properties of wavelet transform and fractional random transform. Possible applications of the proposed transform are in biometrics, image compression, image transmission, transient signal processing, etc. In this correspondence paper, biometrics is chosen as the primary application; and hence, a new technique is proposed for securing fingerprints during communication and transmission over insecure channel. © 2012, IEEE