Digital Image Watermarking is one of the ways to protect intellectual property right and copyright of the information owner. Fidelity, Capacity and Robustness are the important requirements of digital watermarking techniques, but these requirements compete with each other; if one is improved the other two are affected. This paper presents a combined approach of DWT, Chirp-Z and Fast Walsh-Hadam...

We describe a new approach to analyze chirp syllables of free-tailed bats from two regions of Texas in which they are predominant: Austin and College Station. Our goal is to characterize any systematic regional differences in the mating chirps and assess whether individual bats have signature chirps. The data are analyzed by modeling spectrograms of the chirps as responses in a Bayesian functio...

A new four-parameter atomic decomposition of chirplets is developed for compact representation of signals with chirp components. The four-parameter atom is obtained by scaling the Gaussian function, and then applying the fractional Fourier transform (FRFT), timeshift and frequency-shift operators to the scaled Gaussian. The decomposition is realized by extending the matching pursuit algorithm t...

Signal classification has many important applications in both of the civilian and military domains. This paper presents a classification of multi-user chirp modulation signals using wavelet higher order statistics features and neural network classifier (NN). In this paper, even higher order moments and cumulants up to order eight from the discrete wavelet transform (DWT) coefficients are propos...

A novel switched excitation method for linear frequency modulated excitation of ultrasonic transducers in pulse compression systems is presented that is simple to realise, yet provides reduced signal sidelobes at the output of the matched filter compared to bipolar pseudo-chirp excitation. Pulse compression signal sidelobes are reduced through the use of simple amplitude tapering at the beginni...

This paper describes an eddy current (EC) based non-destructive testing system used for experimental verification of optimized chirp signal. The time-frequency content of the EC driving signal is synthesized with respect to material properties. We are expecting an improvement in sensitivity of crack and corrosion detection.

In Europe, several species of crickets are available commercially as pet food. Here we investigated the calling song and phonotactic selectivity for sound patterns on the short and long time scales for one such a cricket, Gryllus spec., available as "Gryllus assimilis", the Steppengrille, originally from Ecuador. The calling song consisted of short chirps (2-3 pulses, carrier frequency: 5.0 kHz...