Now showing items 1-10 of 85
JPEG Compression History Estimation for Color Images
We routinely encounter digital color images that were previously JPEG-compressed. We aim to retrieve the various settings - termed JPEG compression history (CH) - employed during previous JPEG operations. This information ...
Multiscale Connection-Level Analysis of Network Traffic
Network traffic exhibits drastically different statistics, ranging from nearly Gaussian marginals and long range dependence at very large time scales to highly non-Gaussian marginals and multifractal scaling on small scales. ...
Orthogonal Hilbert Transform Filter Banks and Wavelets
Complex wavelet transforms offer the opportunity to perform directional and coherent processing based on the local magnitude and phase of signals and images. Although denoising, segmentation, and image enhancement are ...
Wavelet Statistical Models and Besov Spaces
Terahertz Multistatic Reflection Imaging
We describe a new imaging method using single-cycle pulses of terahertz (THz) radiation. This technique emulates the data collection and image processing procedures developed for geophysical prospecting and is made possible ...
Distributed Compressed Sensing of Jointly Sparse Signals
Compressed sensing is an emerging field based on the revelation that a small collection of linear projections of a sparse signal contains enough information for reconstruction. In this paper we expand our theory for ...
Asymptotic Performance of Transmit Diversity via OFDM for Multipath Channels
Many wireless systems exploit transmit diversity for more reliable detection of signals at the receiver. To accomplish this, coding is spread across multiple transmit antennas. An example of this is the well known "Alamouti ...
Contraction, Smoothness, and Low-Pass Filtering
We introduce a generalized definition for "low-pass" filters that covers time-varying and nonlinear systems under the same umbrella. We show that the qualitative concept of signal smoothing can be made precise through the ...
Imaging with Terahertz Pulses
Recently, a real-time imaging system based on terahertz (THz) time-domain spectroscopy has been developed. This technique offers a range of unique imaging modalities due to the broad bandwidth, sub-picosecond duration, and ...
Development of Digital Signal Processor controlled Quantum Cascade Laser based Trace Gas Sensor Technology
This work reports the design and integration of a custom digital signal processor (DSP) system into a pulsed quantum cascade laser (QCL) based trace gas sensor to improve its portability, robustness and operating performance. ...