Cumulant based identification approaches for nonminimum phase FIR systems

Cataloged from PDF version of article.In this paper, recursive and least squares methods for identification of nonminimum phase linear time-invariant (NMP-LTI) FIR systems are developed. The methods utilize the second- and third-order cumulants of the output of the FIR system whose input is an independent, identically distributed (i.i.d.) non-Gaussian process. Since knowledge of the system order is of utmost importance to many system identification algorithms, new procedures for determining the order of an FIR system using only the output cumulants are also presented. To illustrate the effectiveness of our methods, various simulation examples are presented

A Phase Reconstruction Algorithm From Bispectrum

A new computationally efficient procedure for the reconstruction of the impulse response of a (minimum or nonminimum phase) linear time-invariant (LTI) system from its bispectrum is presented. This method is based on computing the cepstrum of the impulse response sequence from the ω1 = ω2 slice of the bispectrum. The algorithm can be implemented by using only the one-dimensional fast Fourier transform algorithm. © 1990 IEE

Cumulant based parametric multichannel FIR system identification methods

Cataloged from PDF version of article.In this paper, ''least squares'' and recursive methods for simultaneous identification of four nonminimum phase linear, time-invariant FIR systems are presented. The methods utilize the second- and fourth-order cumulants of outputs of the four FIR systems of which the common input is an independent, identically distributed (i.i.d.) non-Gaussian process. The new methods can be extended to the general problem of simultaneous identification of three or more FIR systems by choosing the order of the utilized cumulants to be equal to the number of systems. To illustrate the effectiveness of our methods, two simulation examples are included

Hardware realization of a novel Automatic Censored Cell Averaging CFAR detection algorithm using FPGA

In this paper we present hardware realization of a novel Automatic Censored Cell Averaging (ACCA) Constant False Alarm Rate (CFAR) detection algorithm based on Ordered Data Variability (ODV) using Field Programmable Gate Array (FPGA). This algorithm has been recently proposed in the literature for radar target detection in non-homogeneous environments. The unknown background level can be estimated by dynamically selecting a suitable set of ranked reference window cells and by doing successive hypothesis tests. The ACCA-ODV based CFAR detector does not require any prior information about the background environment and uses the variability index statistic as a shape parameter to reject or accept the ordered cells under investigation. Recent advancements in modern FPGAs and availability of sophisticated electronic design tools have made it possible to realize the ACCA-ODV CFAR detector in a cost-effective way. The designed hardware is modular and has been physically realized in Altera Stratix II FPGA device. © 2008 IEEE.International Conference on Signal Processin

Robust and secure fractional wavelet image watermarking

This paper presents an efficient fractional wavelet transform (FWT) image watermarking technique based on combining the discrete wavelet transform (DWT) and the fractional Fourier transform (FRFT). In the proposed technique, the host image is wavelet transformed with two resolution levels, and then, the middle frequency sub-bands are FRFT transformed. The watermark is hidden by altering the selected FRFT coefficients of the middle frequency sub-bands of the 2-level DWT-transformed host image. Two pseudo-random noise (PN) sequences are used to modulate the selected FRFT coefficients with the watermark pixels, and inverse transforms are finally applied to get the watermarked image. In watermark extraction, we just need the same two PN sequences used in the embedding process and the watermark size. The correlation factor is used to determine whether the extracted pixel is one or zero. The proposed fractional wavelet transform (FWT) image watermarking method is tested with different image processing attacks and under composite attacks to verify its robustness. Experimental results demonstrated improved robustness and security

EFFICIENT ITERATIVE DECONVOLUTION OF NOISY WAVEFORMS.

A simplified but reliable design procedure is proposed for the deconvolution noise reduction compensators of S. M. Riad and Nahman-Guillaume. This procedure produces a compensator that yields close to optimum deconvolution results with the least possible iterations

Structured Light Transmission under Free Space Jamming: An Enhanced Mode Identification and Signal-to-Jamming Ratio Estimation Using Machine Learning

In this paper, we develop new classification and estimation algorithms in the context of free space optics (FSO) transmission. Firstly, a new classification algorithm is proposed to address efficiently the problem of identifying structured light modes under jamming effect. The proposed method exploits support vector machine (SVM) and the histogram of oriented gradients algorithm for the classification task within a specific range of signal-to-jamming ratio (SJR). The SVM model is trained and tested using experimental data generated using different modes of the structured light beam, including the 8-ary Laguerre Gaussian (LG), 8-ary superposition-LG, and 16-ary Hermite Gaussian (HG) formats. Secondly, a new algorithm is proposed using neural networks for the sake of predicting the value of SJR with promising results within the investigated range of values between −5 dB and 3 dB

Optical image encryption based on chaotic baker map and double random phase encoding

This paper presents a new technique for optical image encryption based on chaotic Baker map and Double Random Phase Encoding (DRPE). This technique is implemented in two layers to enhance the security level of the classical DRPE. The first layer is a pre-processing layer, which is performed with the chaotic Baker map on the original image. In the second layer, the classical DRPE is utilized. Matlab simulation experiments show that the proposed technique enhances the security level of the DRPE, and at the same time has a better immunity to noise