Vamshi Velmajala - Academia.edu (original) (raw)
Uploads
Papers by Vamshi Velmajala
Data authentication and data security are the primary requisites in present day communication sys... more Data authentication and data security are the primary requisites in present day communication systems. Due to improvements in imaging technologies and the ease with which digital content can be created and manipulated, there is need for the copyright protection of digital content. It is also essential to have techniques for authentication of the content as well as the owner. Digital watermarking seems to be one of the most promising methods for copyright protection of digital images, authentication, labeling and monitoring. This paper proposes a robust and transparent scheme of watermarking that exploits the human visual systems and algorithms which overcome the various disadvantages over DCT and DWT.
A new class of scale invariant feature point detectors, which is robust to transformations like rotation, scale and translation, is introduced and later applied for watermarking. A comparison between two scale-invariant feature point detectors i.e.,
- SIFT feature point detector and Harris-Affine feature point detector, showed that the SIFT feature point detector gives more robust feature points for the most of the geometrical distortions (e.g. rotation, scaling or combinations of them).
In order to detect the parameters of undergone affine transformation, we propose an image registration technique which is based on use of the scale invariant feature point detector. Another proposed technique for watermark synchronization is also based on use of scale invariant feature point detector. This technique does not use the original image to determine the parameters of affine transformation which include rotation and scaling. It is experimentally confirmed that this technique gives excellent results under tested geometrical distortions. Here the complex wavelets were introduced as an alternative to conventional real wavelets. They overcome two main drawbacks of real wavelets: a) lack of shift invariance and b) directional selectivity.
The model focuses not only on the watermarking method, but also on the detector’s capabilities. This is achieved by selecting several regions in an attacked watermarked image, which hold sufficient information about the watermark, and trying to apply an inverse operation in order to extract the watermark. This paper demonstrates various attacks like JPEG Compression, Gaussian Noise and Median Filtering on the selected images and shows how our proposed algorithms can be impervious towards them practically using the Matlab codes.
Digital signal processing (DSP) is the technology that is omnipresent in almost every engineering... more Digital signal processing (DSP) is the technology that is omnipresent in almost every engineering discipline. A typical processor devotes a considerable amount of processing time in performing arithmetic operations, particularly multiplication operations. Multiplication is one of the basic arithmetic operations and it requires substantially more hardware resources and processing time than addition and subtraction. In fact, 8.72% of all the instruction in typical processing units is multiplication. The core computing process is always a multiplication routine; therefore, DSP engineers are constantly looking for new algorithms and hardware to implement them. Vedic mathematics is the name given to the ancient system of mathematics, which was rediscovered, from the Vedas between 1911 and 1918 by Sri Bharati Krishna Tirthaji. The whole of Vedic mathematics is based on 16 sutras (word formulae) and manifests a unified structure of mathematics. This paper presents the design of a low power high speed algorithms for arithmetic logic units using this ancient mathematics techniques and also their hardware implementation. Even convolution algorithms using this technique are discussed along with their FGPA implementation. Employing these techniques in the computation algorithms of the coprocessor has reduced the complexity, execution time, area, power. Further research prospects may include the design and development of a Vedic DSP chip using VLSI technology
Data authentication and data security are the primary requisites in present day communication sys... more Data authentication and data security are the primary requisites in present day communication systems. Due to improvements in imaging technologies and the ease with which digital content can be created and manipulated, there is need for the copyright protection of digital content. It is also essential to have techniques for authentication of the content as well as the owner. Digital watermarking seems to be one of the most promising methods for copyright protection of digital images, authentication, labeling and monitoring. This paper proposes a robust and transparent scheme of watermarking that exploits the human visual systems and algorithms which overcome the various disadvantages over DCT and DWT.
A new class of scale invariant feature point detectors, which is robust to transformations like rotation, scale and translation, is introduced and later applied for watermarking. A comparison between two scale-invariant feature point detectors i.e.,
- SIFT feature point detector and Harris-Affine feature point detector, showed that the SIFT feature point detector gives more robust feature points for the most of the geometrical distortions (e.g. rotation, scaling or combinations of them).
In order to detect the parameters of undergone affine transformation, we propose an image registration technique which is based on use of the scale invariant feature point detector. Another proposed technique for watermark synchronization is also based on use of scale invariant feature point detector. This technique does not use the original image to determine the parameters of affine transformation which include rotation and scaling. It is experimentally confirmed that this technique gives excellent results under tested geometrical distortions. Here the complex wavelets were introduced as an alternative to conventional real wavelets. They overcome two main drawbacks of real wavelets: a) lack of shift invariance and b) directional selectivity.
The model focuses not only on the watermarking method, but also on the detector’s capabilities. This is achieved by selecting several regions in an attacked watermarked image, which hold sufficient information about the watermark, and trying to apply an inverse operation in order to extract the watermark. This paper demonstrates various attacks like JPEG Compression, Gaussian Noise and Median Filtering on the selected images and shows how our proposed algorithms can be impervious towards them practically using the Matlab codes.
Digital signal processing (DSP) is the technology that is omnipresent in almost every engineering... more Digital signal processing (DSP) is the technology that is omnipresent in almost every engineering discipline. A typical processor devotes a considerable amount of processing time in performing arithmetic operations, particularly multiplication operations. Multiplication is one of the basic arithmetic operations and it requires substantially more hardware resources and processing time than addition and subtraction. In fact, 8.72% of all the instruction in typical processing units is multiplication. The core computing process is always a multiplication routine; therefore, DSP engineers are constantly looking for new algorithms and hardware to implement them. Vedic mathematics is the name given to the ancient system of mathematics, which was rediscovered, from the Vedas between 1911 and 1918 by Sri Bharati Krishna Tirthaji. The whole of Vedic mathematics is based on 16 sutras (word formulae) and manifests a unified structure of mathematics. This paper presents the design of a low power high speed algorithms for arithmetic logic units using this ancient mathematics techniques and also their hardware implementation. Even convolution algorithms using this technique are discussed along with their FGPA implementation. Employing these techniques in the computation algorithms of the coprocessor has reduced the complexity, execution time, area, power. Further research prospects may include the design and development of a Vedic DSP chip using VLSI technology