Falih H. Ahmad

Tau method approximation for radiative transfer problems in a slab medium

An approximate method for solving the radiative transfer equation in a slab medium with an isotropic scattering is proposed. The method is based upon constructing the double Legendre series to approximate the required solution using Legendre tau method. The differential and integral expressions which arise in the radiative transfer equation are converted into a system of linear algebraic equations which can be solved for the unknown coefficients. Numerical examples are included to demonstrate the validity and applicability of the method and a comparison is made with existing results.

A pseudospectral technique for the discrete reconstruction of the three-dimensional equivalent-current density

In this paper, a new technique is developed to reconstruct the three dimensional equivalent-current density associated with a dielectric scatterer with an arbitrary shape. This technique is based on the solution of an integral equation using a pseudospectral method where part of the integrand represents the unknown. The other part of the integrand is the known dyadic Greens function. This technique generates accurate results, which makes it attractive for electromagnetic inversion of scatters from inhomogeneous dielectric bodies. An example is given to demonstrate the accuracy of the developed technique.

Lagrange Gradient Mask for Optical Image Processing

Masks are used in optical image processing. They are used to generate gradient maps. These maps are applica- ble to the enhancement of feature extraction and edge detection. Lagrange mask is presented in this letter and criteria for the characterizations of mask performance are given. Through an illustration the performance of the presented mask is demonstrated where it is compared to that of Gabor mask. Results from the illustration support the applicability and suit- ability of Lagrange mask for the generation of gradient maps from a noise corrupted optical image.

A discrete bidirectional reflectance model in remote sensing

A numerical scheme is devised to develop a discrete bidirectional reflectance model. A pseudospectral method is utilized with which the discrete solution of the radiative transfer equation is made part of this development. To produce discrete bidirectional reflectance values, a set of algebraic equations is solved. Illustrative examples are given to demonstrate the performance of the developed model.

A WAVELET PACKETS TECHNIQUE FOR THE DETECTION OF ANOMALIES IN FOURIER TRANSFORM INFRARED INTERFEROGRAMS

ABSTRACT A technique that integrates applications of wavelet packets and principal component analysis is developed. This technique is applied for the purpose of detecting anomalies in Fourier Transform Infrared (FTIR) interferograms. An experimental example is given to demonstrate the performance of this technique.

A legendre wavelet method for the radiative transfer equation in remote sensing

An approximate method for solving radiative Transfer equation in a slab medium with an isotropic scattering is presented. The method is based upon Legendre wavelets approximations. The differential and integral expressions which arise in the radiative transfer equation are converted into some linear systems of differential equations which can be solved for the unknown coefficient. Numerical examples are included to demonstrate the validity and applicability of the technique and a comparison is made with existing results.

Interferogram phase evaluation through a differential equation technique

A technique for the evaluation of the unknown phase of a spatial carrier interferogram is proposed in this paper. This technique is based on the formulation of a differential equation for the unknown phase. The coefficients of this equation are known functions. They are formulated with the aid of a modified Fourier transform method and Hilbert transform where they are functions of the measured interferogram. This equation is made discrete and solved through the application of a pseudospectral method. An illustrative example is given in which this technique is applied. Results generated from the application of this technique are compared with exact phase values, and exemplary agreement between the exact and approximate phase values is demonstrated.

A direct method for phase approximation of interferograms

A direct method that generates an approximation of the unknown phase of an interferogram is proposed in this paper. The method is based on finding an expression for the derivative of the unknown phase which is integrated to generate such approximation. An illustrative example is given in which this method is applied. Results generated from the application of this method are compared with exact phase values, and excellent agreement between the exact and approximate phase values is demonstrated.