The pyramid algorithm for computing single wavelet transform coefficients is well known. The pyramid algorithm can be implemented by using tree-structured multirate filter banks. In this paper, we propose a general algorithm to compute multiwavelet transform coeficients by adding proper premultirate filter banks before the vector filter banks that generate multiwavelets. The proposed algorithm ...

In this paper, we proposed a new method for spatially registered multi-focus images fusion. Image fusion based on wavelet transform is the most commonly fusion method, which fuses the source images information in wavelet domain according to some fusion rules. There are some disadvantages in Discrete Wavelet Transform, such as shift variance and poor directionality. Also, because of the uncertai...

This paper introduces the use of adaptive multichannel discrete wavelet transforms (AMDWTs), allowing for a customized design of optimum mother wavelets, for the detection of a constituent absorption band within a hyperspectral curve. Even when the target’s amplitude is only 3% of the background signal’s amplitude, the AMDWT approach produces target detection rates of 90%.

Cardiovascular problems are among the leading causes of mortality in the World. It is estimated that about 15 % of the world population has died due to cardiovascular problems. In Brazil this number represents almost 30 % of deaths, being the men the most affected by cardiovascular disease, with a percentage of approximately 60 % of the victims. Another alarming factor is that Brazil is among t...

In this article, the authors investigate the multi-scale structure of the S&P500 minute-by-minute time series. The authors attempt to find the answer to the following question: Are upward and downward regimes in the S&P500 time series exhibit different long-range power-law correlations? To answer this question, the authors apply the discrete wavelet transform (DWT) to the original time series f...

Article history: Available online 29 April 2014

Until now, most exposure fusion methods are easy to be influenced by the location of object in the image. However, when capturing the source images, slight shift in the camera’s position will yield blurry or double images. In order to solve the problem, a method called SIDWTBEF is proposed, which is based on shift-invariant discrete wavelet transform (SIDWT). It is more robust to images those h...

Images require substantial storage and transmission resources, thus image compression is advantageous to reduce these requirements. The objective of this paper is to evaluate a set of wavelets for image compression. Image compression using wavelet transforms results in an improved compression ratio. Wavelet transformation is the technique that provides both spatial and frequency domain informat...

Translation and convolution associated with discrete wavelet transform are investigated using properties of Calderón-Zygmund operator and Riesz fractional integral operator. Dual convolution is also studied. The wavelet convolution is applied to approximate functions belonging to certain p L-spaces.