We present a new measure of image focus. It is based on wavelet transform of the image and is defined as a ratio of high-pass band and low-pass band norms. We show this measure is monotonic with respect to the degree of defocusation and sufficiently robust. We experimentally illustrate its performance on simulated as well as real data and compare it with existing focus measures (gray-level vari...

Abstract. In this paper, we study wavelet filters and their dependence on two numbers, the scale N and the genus g. We show that the wavelet filters, in the quadrature mirror case, have a harmonic analysis which is based on representations of the C∗-algebra ON . A main tool in our analysis is the infinite-dimensional group of all maps T → U (N) (where U (N) is the group of all unitary N-by-N ma...

In the present work, we present a new formulation for the estimation of the soil moisture in the root zone based on the measured value of soil moisture at the surface. The method sheds lights on the relationship between surface and root zone soil moisture. It derives from a simplified form of the soil water balance equation and provides a closed form of the relationship between the root zone an...

A 2D biomechanical model of the tongue is used to simulate movement sequences and speech signals in Vowel-to-Vowel transitions. The analysis is focused on how central commands and biomechanics can interact and influence the physical speech signals. In particular, it is shown how complex velocity profiles can be explained by the biomechanics, and how the low-pass filtering effect of the biomecha...

In the paper we present an improved version of multistage hashing based algorithm, used to find frequent items in a stream. Our algorithm uses low-pass filters instead of simple counters, so it concentrates more on recent items and ignores the old ones. Such behaviour is similar to sliding window based algorithms, but requires less memory and is suitable for real-time applications. The algorith...

This study compares learning from designing instruction in the context of simulation-based inquiry learning with learning from expository teaching. The domain of instruction was the electricity domain of high-pass and low-pass filters. Participants were students from a technical vocational school. In the experimental condition (N = 21) students created assignments for an imaginary student to he...

In this paper we present the tau-cell, a building block based on a log-domain low-pass filter, which allows the creation of arbitrary differential equations using a cascade of these cells in a manner similar to the state variable methods of filter realization. In the tau-cell implementation, however, all feedback is local, i.e., each first-order section only feeds back to the previous firstorde...

Noise analysis of higher-order translinear filters cannot be established through straight-forward extension of analysis techniques for first-order TL filters, due to the presence noise sources that interact with multiple filter states simultaneously, in a nonlinear and non-stationary way. Such noise sources, that are not encountered in in first-order TL filters, require a new analysis technique...

Many experimental studies demonstrate a match between the transfer function of sensory neurons and the statistics of natural stimuli. However, neurons might not be able to adapt to any given stimulus statistics due to very basic constraints. The high-pass nature of spike-frequency adaptation (Benda and Herz, 2003) emphasizes fast stimulus components over slow stimuli (Benda et al., 2005). The c...

In this work, we are interesting in the analysis and the design of an ultra wideband (UWB) band pass filter with improved upper stop band performances, using microstrip lines. The design of the UWB band pass filter is based on the use of stepped-impedance low pass filter and high pass filter; whereas the simulation of its frequency response ([S]) is done using MATPAR software and it is based on...