Vikas Saxena

Remote sensing image registration techniques: a survey

Image Registration is the first step towards using remote sensed images for any purpose. Despite numerous techniques being developed for image registration, only a handful has proved to be useful for registration of remote sensing images due to their characteristic of being computationally heavy. Recent flux in technology has prompted a legion of approaches that may suit divergent remote sensing applications. This paper presents a comprehensive survey of such literatures including recently developed techniques.

An Improved and Robust DCT Based Digital Image Watermarking Scheme

The need for displaying one„s own multimedia content on the internet is increasing day by day. With the exponential growth of internet and high speed networks operating through out the world it‟s a challenging task to protect copyright of an individual‟s creation. Digital watermarking provides a viable solution to protect copyright and authenticate the ownership of an intellectual property. In this paper we propose a new DCT based additive watermarking scheme which provides higher resistance to image processing attacks mainly JPEG compression. In our approach the watermark is embedded in the mid frequency band of the DCT blocks only in the sub band which is carrying low frequency components and the high frequency sub band components remain untouched. General Terms Discrete Cosine Transform (DCT), Discrete Wavelet Transform (DWT), Discrete Image watermarking, Joint Photographic Experts Group (JPEG), JPEG Quality Factor (Q), Peak Signal to Noise Ratio (PSNR)

Augmented Chemistry: Interactive Education System

knowledge delivery methods in education should move away from memory based learning to more motivated and creative education. This paper will emphasize on the advantages tangible interaction can bring to education. Augmented Chemistry provides an efficient way for designing and interacting with the molecules to understand the spatial relations between molecules. For Students it is very informative to see actual molecules representation 3D environment, inspect molecules from multiple viewpoints and control the interaction of molecules.We present in this paper an Augmented Reality system for teaching spatial relationships and chemical-reaction problem-solving skills to school-level students based on the VSEPR theory. Our system is based on inexpensive webcams and open-source software. We hope this willgenerate more ideas for educators and researcher to explore Augmented Reality technology in the field of interactive education.

A performance analysis of objective video quality metrics for digital video watermarking

Rapid growth in sharing information using internet technologies laid the threats of copyright protection for digital multimedia contents. One of the remedy for intellectual property protection is Watermarking. This paper deals with numerous available digital video watermarking techniques and raised the issue of quality and size of watermarked video. Through experimental study, it has been shown that available quality metrics like, Peak signal to noise ratio (PSNR) and Structural similarity index (SSIM) are incapable to deal efficiently to analyze the quality degradation but out of two it has been claimed that SSIM results are more accurate as it is closer to the results obtained during subjective quality analysis. Further, using available video watermarking tools, variation in size of video has been analyzed.

Collusion Attack Resistant Watermarking Scheme for Images using DCT

Image Watermarking with both insensible detection and high robustness capabilities is still a challenging problem for copyright protection up to now. This paper presents a new scheme for watermarking of still image by introducing redundancy in conjunction with low frequency coefficient, in classical middle frequency coefficients exchange scheme to make it collusion attack resistant. Experimental results show the robustness of the proposed scheme against the JPEG compression and other common image manipulations.

Anomaly Detection in network traffic and role of wavelets

Network Anomaly Detection covers wide area of research. Current best practices for identifying and diagnosing traffic anomalies consist of visualizing traffic from different perspectives and identifying anomalies from prior experience. Different tools have been developed to automatically generate alerts to failures, but to automate the anomaly identification process remains a challenge. Recently, Signal Processing techniques have found applications in Network Intrusion Detection System because of their ability in detecting novel intrusions and attacks, which cannot be achieved by signature-based detection systems. Visualization techniques are ways of creating and handling graphical representations of data. This survey explains the main techniques known in the field of Statistical based and Wavelet based anomaly detection approaches and focuses on the role of data traffic visualization tools in network traffic anomaly detection.

A digital audio watermarking scheme using selective mid band DCT coefficients and energy threshold

In this paper, two blind digital audio watermarking technique are proposed according to the payload requirement which uses discrete cosine transform (DCT). In our method the watermark is embedded into the selected mid band coefficients of the DCT transformed audio. The selected coefficients are middle band DCT coefficients which are modified and quantized through the average energy of the selected sub frame for watermark embedding. The mid band frequency components are selected through experiments such that the effect of mp3 compression and the common signal processing operation has a minimum effect on these coefficients. Original audio will not be required for extraction of the watermark. To adapt to the mp3 attack a preprocessing step is embedded which did an mp3 conversion of the audio and convert again the audio to the original format prior to embedding. Also embedding is done on the selected blocks which satisfies minimum energy threshold. Experiments show that our scheme produces imperceptible audios and the watermarked audio is robust against common signal processing attacks.

A multi scale approach to distinguish flash crowds from PDDoS attacks

The distributed denial of service attacks have become more sophisticated. The new pulsating denial of service attacks have been found to be heavily damaging to the users and servers. The legitimate flash events have similarity with pulsating distributed denial of service attacks. The presence of self-similarity in computer network traffic has introduced a newer dimension in techniques being developed for anomaly detection in aggregated network traffic. We have tried to use wavelets to distinguish between flash events and pulsating distributed denial of service attacks. Secondly, for any network administrator it is always easier to identify irregularity in the traffic through images therefore we have developed multi-resolution analysis map to represent our attack detection mechanism.

Advanced free-form deformation and Kullback–Lieblier divergence measure for digital elevation model registration

Registration is the process of transforming various images of the same object, place, etc. to confer one coordinate system, be they multimodal, multi-temporal of the same place or images of different places having certain common characteristics. Many methods have been tried for image registration; however, only a handful of methods may be said to work for digital elevation model (DEM) registration. The motivation of the present work is to perform a robust and efficient algorithm to perform Elevation model image registration. In this paper, we present a new approach for DEM registration, particularly for multimodal or multi-temporal DEMs. For time efficient, robust and precise registration of DEMs, a novel idea has been proposed using rational DMS-spline volumes (Xu et al. in J Comput Sci Technol 23(5):862–873, 1996; McDonnell and Qin in J Gr Tools 12(3):24–41, 2007) (the term DMS is acronym for the three authors, namely Dahmen et al. in Math Comput 59(199):97–115, 1997). This is based on the usage of arbitrary topology lattices (MacCracken and Joy in 23rd annual conference on computer graphics and interactive techniques proceedings. ACM-SIGGRAPH, pp 181–188, 1996; Feng et al. in Vis Comput Int Comput Gr 22(1):28–42, 2005). Using free-form deformation has lead to the usage of global and local transformations for registration of candidate image domain to reference image domain. Also, a similarity measure based on Kullback–Leibler divergence (KLD) has been used for measuring robustness of the method so proposed. The task of registration is achieved by minimizing the cost function using rational DMS-spline functions for local registration. After experimentations, the results show that the registration process, of registration of candidate DEM to reference DEM, could be completed successfully. Comparison of similarity measurement methods such as mutual information, correlation coefficient and peak signal-to-noise ratio with that of KLD-based has been performed. Comparative study with existing works suggests that the presented scheme is better, when compared with respect to above mentioned parameters.

Towards Increasing the Robustness of Image Watermarking Scheme Against Histogram Equalization Attack

Image watermarking with both insensible detection and high robustness capabilities is still a challenging problem for copyright protection up to now. Transformed domain has been found more suitable to hide the watermark data. For watermark embedding, transformed domain based watermarking schemes are quite robust against those attacks which anyhow do not have large impact on perceptual quality like JPEG compression. This paper explores an opportunity to improve the robustness of transformed domain based watermarking schemes by preprocessing the image. This attempt is to find whether we can make our images strong enough against such attacks in advance. We are considering histogram equalization attack that has impact on perceptual quality.