This article gives an overview on nonparametric modelling of nonstationary time series and estimation of their time-changing spectral content by modern denoising (smoothing) methods. For the modelling aspect localized decompositions such as various local Fourier (spectral) representations are discussed, among which wavelet and local cosine bases are most prominent ones. For the estimation of th...

In this paper, we present variants of the Dual-Tree Complex Wavelet Transform (DT-CWT) in order to automatically classify endoscopic images with respect to the Marsh classi cation. The feature vectors either consist of the means and standard deviations of the subbands from a DT-CWT variant or of the Weibull parameter of these subbands. To reduce the e ects of di erent distances and perspectives...

In this work a Discrete Cosine Transform (DCT)-based feature dimensionality reduced approach for fingerprint matching is proposed. The DCT is applied on a small region around the core point of fingerprint image. The performance of our proposed method is evaluated on a small database of Bologna University and two large databases of FVC2000. A dimensionally reduced feature vector is formed using ...

Copyright protection has become a need in today’s world. To achieve a secure copyright protection we embedded some information in images and videos and that image or video is called copyright protected. The embedded information can’t be detected by human eye but some attacks and operations can tamper that information to breach protection. So in order to find a secure technique of copyright prot...

In traditional watermarking algorithms, the insertion of watermark into the host signal inevitably introduces some perceptible quality degradation. Another problem is the inherent conflict between imperceptibility and robustness. Zero-watermarking technique can solve these problems successfully. Instead of embedding watermark, the zero-watermarking technique extracts some essential characterist...

{ It has been demonstrated that wavelets compete well against DCT based image compression techniques 1]. However the advantages of nonseparable wavelet transforms for image and video coding have not yet been adequately explored. In this paper we discuss nonseparable wavelet transforms on the quincunx lattice and show that they have certain properties which make them an attractive choice for ima...

This paper describes an efficient watermarking technique for use to protect fingerprint images. The rationale is to embed the watermarks into the ridges area of the fingerprint images so that the technique is inherently robust, yields imperceptible watermarks, and resists well against cropping and/or segmentation attacks. The proposed technique improves the performance of optimum multibit water...

With the help of various image editing tools available, it has become easier to alter an image in such a way that it does not leave behind any clues. Copy –Move forgery or also known as Region Duplication Forgery is a type of image forgery in which a part of digital image is copied and pasted to another part of same image. Since the copied and pasted image comes from the same image, it becomes ...

This paper proposes novel lossy image compression technique using hybrid wavelet transform and vector quantization. First hybrid wavelet transform consisting of two different component transforms is generated and applied on color images. Discrete Kekre transform (DKT) and Discrete Cosine transform (DCT) play role of base and local transform respectively in hybrid wavelet transform. In transform...

2D convolution and 2D transforms, such as wavelet transform and discrete cosine transform (DCT), are widely used in image and video processing. To reduce the computation complexity, these algorithms are often implemented in two separable passes of 1D processing (e.g., row-wise processing followed by column-wise processing). For example, the number of multiplications of a direct N x N 2D DCT is ...