A time-frequency analysis, which represents the time change of a signal, is significant in all fields. Wigner distribution, a short time Fourier transform (STFT), a kernel method, and a characteristic function method etc. are known as a time-frequency analyzing method, and those methods have merits and demerits. STFT method has been used as ultrasound blood-flow imaging for a long time, because...

We propose a signal based joint time-frequency segmentation algorithm as an extension to Herley et al. (IEEE Trans. Image Processing, 1997). Our algorithm provides an unconstrained multiresolution analysis in time and frequency adapted to the characteristics of the signal, where the time-frequency segmentation of Herley et al. is modified to achieve a minimum entropy criterion. Experimental res...

one of the most fundamental reservoir characteristics is the thickness. the analysis of thin bed tuning on seismic reflectivity has been studied extensively by wides (1973) and neidel and pogiaggliomi (1977), who discussed the limits of seismic resolution. during the past decade, the industry has developed a plethora of new attributes in studying thin beds by employing spectral decomposition (p...

This work was funded in part by the US Air Force Office of Scientific Research under grant F49620-01-1-0446. ABSTRACT Filtering in time-frequency domain involves synthesis of signals with specific time-frequency signature. In this work we observe that watermarking of time-frequency distributions is a similar problem. The proposed domain is the joint time-frequency cells of the Wigner Distributi...

Time-frequency representation of seismic signals provides a source of information that is usually hidden in the Fourier spectrum. The short-time Fourier transform and the wavelet transform are the principal approaches to simultaneously decompose a signal into time and frequency components. Known limitations, such as trade-offs between time and frequency resolution, may be overcome by alternativ...

Many natural phenomena, including geologic events and geophysical data, are fundamentally nonstationary exhibiting statistical variation that changes in space and time. Time-frequency characterization is useful for analyzing such data, seismic traces in particular. We present a novel time-frequency decomposition, which aims at depicting the nonstationary character of seismic data. The proposed ...

The two defining features of G-matrix Fourier transform (GFT) projection NMR spectroscopy are (i) repeated joint sampling of several indirect chemical shift evolution periods of a multidimensional NMR experiment so that transfer amplitudes are generated which are proportional to all possible permutations of cosine and sine modulations of the individual shifts, and (ii) linear combination of the...

An efficient algorithm to reduce the noise from the Nuclear Magnetic Resonance Free Induction Decay (NMR FID) signals is presented, in this paper, via the oversampled real-valued discrete Gabor transform using the Gaussian synthesis window. An NMR FID signal in the Gabor transform domain (i.e., a joint time-frequency domain) is concentrated in a few number of Gabor transform coefficients while ...

Ground penetrating radar (GPR) was used to characterize the frequency-dependent dielectric relaxation phenomena in ordinary Portland cement (OPC) hydration in concrete changing from fresh to hardened state. The study was experimented by measuring the changes of GPR A-scan waveforms over a period of 90 days, and processed the waveforms with short-time Fourier transform (STFT) in joint time-frequ...