Abstract: Diffraction grating is periodic module used in many
engineering fields, its geometrical conception gives interesting
properties of diffraction and interferences, a uniform and periodic
diffraction grating consists of a number of identical apertures that are
equally spaced, in this case, the amplitude of intensity distribution
in the far field region is generally modulated by diffraction pattern
of single aperture. In this paper, we study the case of aperiodic
diffraction grating with identical rectangular apertures where theirs
coordinates are modeled by square root function, we elaborate a
computer simulation comparatively to the periodic array with same
length and we discuss the numerical results.
Abstract: This paper treats different aspects of entropy measure
in classical information theory and statistical quantum mechanics, it
presents the possibility of extending the definition of Von Neumann
entropy to image and array processing. In the first part, we generalize
the quantum entropy using singular values of arbitrary rectangular
matrices to measure the randomness and the quality of denoising
operation, this new definition of entropy can be implemented to
compare the performance analysis of filtering methods. In the second
part, we apply the concept of pure state in quantum formalism
to generalize the maximum entropy method for narrowband and
farfield source localization problem. Several computer simulation
results are illustrated to demonstrate the effectiveness of the proposed
techniques.
Abstract: In this paper, a fifth order propagator operators are proposed for estimating the Angles Of Arrival (AOA) of narrowband electromagnetic waves impinging on antenna array when its number of sensors is larger than the number of radiating sources.
The array response matrix is partitioned into five linearly dependent phases to construct the noise projector using five different propagators from non diagonal blocks of the spectral matrice of the received data; hence, five different estimators are proposed to estimate the angles of the sources. The simulation results proved the performance of the proposed estimators in the presence of white noise comparatively to high resolution eigen based spectra.
Abstract: In this paper, we investigated the effect of real valued transformation of the spectral matrix of the received data for Angles Of Arrival estimation problem. Indeed, the unitary transformation of Partial Propagator (UPP) for narrowband sources is proposed and applied on Uniform Linear Array (ULA).
Monte Carlo simulations proved the performance of the UPP spectrum comparatively with Forward Backward Partial Propagator (FBPP) and Unitary Propagator (UP). The results demonstrates that when some of the sources are fully correlated and closer than the Rayleigh angular limit resolution of the broadside array, the UPP method outperforms the FBPP in both of spatial resolution and complexity.
Abstract: The Maximum entropy principle in spectral analysis
was used as an estimator of Direction of Arrival (DoA) of
electromagnetic or acoustic sources impinging on an array of sensors,
indeed the maximum entropy operator is very efficient when the
signals of the radiating sources are ergodic and complex zero mean
random processes which is the case for cosmic sources. In this paper,
we present basic review of the maximum entropy method (MEM)
which consists of rank one operator but not a projector, and we
elaborate a new operator which is full rank and sum of all possible
projectors. Two dimensional Simulation results based on Monte
Carlo trials prove the resolution power of the new operator where the
MEM presents some erroneous fluctuations.