In this paper we introduce a. multi-scale deconvolution technique performed in the scale-domain. In sensor array applications such as in radar, sonar and seismic processing, the sensor outputs are modeled as the convo...
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ISBN:
(纸本)0819432938
In this paper we introduce a. multi-scale deconvolution technique performed in the scale-domain. In sensor array applications such as in radar, sonar and seismic processing, the sensor outputs are modeled as the convolution of the unknown source signal with various unknown system impulse responses that are scaled versions of each other with unknown scale parameters. In many applications these signals or the scaling parameters are needed to be estimated only from the sensor outputs. In our earlier work, we estimated the unknown scale parameters by using properties of the scale transform and then employed existing deconvolution algorithms. Here, we derive the multiscale blind deconvolution algorithm in the scale transform domain. The performance of the method is illustrated using simulation examples.
This paper is devoted to change detection for precision agriculture. It presents a new change detection methodology and an overview of an online image processing tool (***) with direct applicability for crop classific...
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ISBN:
(纸本)0819450782
This paper is devoted to change detection for precision agriculture. It presents a new change detection methodology and an overview of an online image processing tool (***) with direct applicability for crop classification. The change detection algorithms discussed in the paper will be implemented on the web. They preserve the fine details of the pixel changes and furthermore may be used for crop classification. Image registration, calibration/normalization, pixel level transformations, clutter suppression and pixel level change detection are discussed and new technologies are presented. The effectiveness of the proposed technology is being tested on real SAR data with partial truthing.
This paper considers ''blind beamforming'' operations on a wireless network of randomly distributed MEM sensors. Maximum power collection criterion is proposed and results in array weights obtained fro...
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ISBN:
(纸本)0819425842
This paper considers ''blind beamforming'' operations on a wireless network of randomly distributed MEM sensors. Maximum power collection criterion is proposed and results in array weights obtained from the eigenvector corresponding to largest eigenvalue of a matrix eigenvalue problem. Theoretical justification of this approach to an extension of Szego's asymptotic distribution of eigenvalues is provided. Numerical results on propagation time delay estimation and loss of coherency due to propagation disturbances are presented.
In this paper, under the assumption that noise correlation is spatially limited, using two separated arrays, we propose a new parametric approach for consistent directions of arrival (DOA) estimations in unknown noise...
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ISBN:
(纸本)081940943X
In this paper, under the assumption that noise correlation is spatially limited, using two separated arrays, we propose a new parametric approach for consistent directions of arrival (DOA) estimations in unknown noise environments. The theoretical performance analysis of the proposed DOA estimations is also presented. With the use of the theoretical performance, the best weighting matrices of the parametric criteria have been derived. More significantly, it has been shown that within the best weighted criteria, using canonical decomposition, we can achieve optimal performance of the DOA estimation among a large set of eigendecompositions.
Higher-order Wigner distributions are not unique: definitions differ in the lag separations between the terms used in the time-domain product, as well as in how many of the terms are conjugated. We study a class of th...
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ISBN:
(纸本)081940943X
Higher-order Wigner distributions are not unique: definitions differ in the lag separations between the terms used in the time-domain product, as well as in how many of the terms are conjugated. We study a class of third-order WDs (TWD), parameterized by a single parameter (alpha) , and show that there is a duality between the choices of (alpha) equals -1/3 (Gerr's definition) and (alpha) equals -1. Interesting signal attributes, such as the instantaneous frequency, the derivative of the log-magnitude, and the group delay can be recovered from the TWD. Important issues such as aliasing problems and sampling requirements, and whether or not the analytic form of a real signal should be used, are addressed. It is shown theoretically that the TWD with (alpha) equals -1 is particularly useful for the detection of transients in the presence of colored Gaussian noise.
A new high-performance systolic architecture for calculating the discrete Fourier transform (DFT) is described which is based on two levels of transform factorization. One level uses an index remapping that converts t...
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A new high-performance systolic architecture for calculating the discrete Fourier transform (DFT) is described which is based on two levels of transform factorization. One level uses an index remapping that converts the direct transform into structured sets of arithmetically simple four-point transforms. Another level adds a row/column decomposition of the DFT. The architecture supports transform lengths that are not powers of two or based on products of coprime numbers. Compared to previous systolic implementations, the architecture is computationally more efficient and uses less hardware. It provides low latency as well as high throughput, and can do both one- and two-dimensional DFTs. An automated computer-aided design tool was used to find latency and throughput optimal designs that matched the target field programmable gate array structure and functionality.
The primary basis for adaptive radar algorithm design is that (1) a Binary Hypothesis formulation with unknown parameters is an adequate test and (2) that radar interference is composed of combinations of thermal nois...
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ISBN:
(纸本)0819425842
The primary basis for adaptive radar algorithm design is that (1) a Binary Hypothesis formulation with unknown parameters is an adequate test and (2) that radar interference is composed of combinations of thermal noise, self induced clutter, and extraneous noise. This is the typical generalized likelihood formulation that yield the CFAR characteristic for the assumed conditions. implementations have shown that such formulations yield inadequate performance in complex clutter environments. As compensation measure, a secondary CFAR process then addresses the potential violation of this assumption by large ''target-like'' interference such as large Clutter discretes or a large number of targets interfering with each other. In order to detect small targets, an approach based on the Likelihood Statistic provides a technique for optimally suppressing the neighboring large signals. Performance is characterized as a function of a generalized distance and relative signal power ratios in the Joint Space-Time domain.
We argue that the standard definition of signal to noise ratio may be misleading when the signal or noise are nonstationary. We introduce a new measure that we call local signal to noise ratio (LSNR) which is well sui...
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ISBN:
(纸本)0819463922
We argue that the standard definition of signal to noise ratio may be misleading when the signal or noise are nonstationary. We introduce a new measure that we call local signal to noise ratio (LSNR) which is well suited to take into account nonstationary situations. The advantage of our measure is that it is a local property unlike the standard SNR which is a single number representing the total duration of the signal. We simulated a number of cases to show that our measure is more indicative of the noise and signal level for nonstationary situations.
We present a general procedure for obtaining equations of motion for the Wigner distribution of functions that are governed by ordinary and partial differential equations. For the case of fields we show that in genera...
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ISBN:
(纸本)0819437611
We present a general procedure for obtaining equations of motion for the Wigner distribution of functions that are governed by ordinary and partial differential equations. For the case of fields we show that in general one must consider Wigner distributions of the four variables, position, momentum, time and frequency. We also show that in general one cannot write an equation of motion for position and momentum however it can be done in some cases, the Schrodinger equation being one such case. Our method leads to an equation of motion for the Schrodinger equation with time dependent potentials in contrast to the result obtained by Wigner and Moyal which was for time independent potentials.
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