Estimating a channel that is subject to frequency selective Rayleigh fading is a challenging problem in an orthogonal frequency division multiplexing (OFDM) system. In this paper we propose an enhanced channel estimation algorithm that combines the EM-based algorithms proposed previously and a Least Squares polynomial fitting (LSPF) approach. The combined algorithm can efficiently estimate the ...

The anterior corneal asphericity (Q) with the tangential radius is calculated, and a three-dimensional (3-D) anterior corneal model is constructed. Tangential power maps from Orbscan II are acquired for 66 young adult subjects. The Q-value of each semimeridian in the near-horizontal region is calculated with the tangential radius. Polynomial fitting is used to model the 360-semimeridional varia...

The ability to construct CAD or other object models from edge and range data has a fundamental meaning in building a recognition and positioning system. While the problem of model fitting has been successfully addressed, the problem of efficient high accuracy and stability of the fitting is still an open problem. In the past researchers have used approximate distance functions rather than the r...

An algebraic curve is defined as the zero set of a polynomial in two variables. Algebraic curves are practical for modeling shapes much more complicated than conics or superquadrics. The main drawback in representing shapes by algebraic curves has been the lack of repeatability in fitting algebraic curves to data. Usually, arguments against using algebraic curves involve references to mathemati...

P-band radar remote sensing applied during the Airborne Microwave Observatory of Subcanopy and Subsurface (AirMOSS) mission has shown great potential for estimation of root zone soil moisture. When retrieving the soil moisture profile (SMP) from P-band radar, a mathematical function describing the vertical moisture distribution is required. Because only a limited number of observations are avai...

Loci of extreme curvature of the topographic surface may be defined by the derivation function (T) depending on the first-, second-, and third-order partial derivatives of elevation. The loci may partially describe ridge and thalweg lines. The firstand second-order partial derivatives are commonly calculated from a digital elevation model (DEM) by fitting the second-order polynomial to a 363 wi...

However, in attempting to find a suitable polynomial approximation to a general function fix), the integral occurring in equation (1.3) cannot be evaluated explicitly, and recourse has to be made to approximate methods for evaluating a„ . The most widely used method is the "curve-fitting" method described by Lanczos [1], and, in greater detail, by Clenshaw and Curtis [2]. There are two variatio...

E. J. Offerman, I. Koktzoglou, C. Glielmi, and R. R. Edelman Radiology, Northshore University HealthSystem, Evanston, IL, United States, Radiology, The University of Chicago, Chicago, IL, United States, Siemens Healthcare, Chicago, IL, United States, Radiology, Northwestern University, Chicago, IL, United States Introduction: Reprojected Line Scan Phase Contrast (rLSPC) MRA is a rapid line scan...

This work presents a new approach to contour representation and coding. It consists of an improved fitting of high-degree (4 to 18) implicit polynomials (IPs) to the contour, which is robust to coefficient quantization. The proposed approach to solve the fitting problem is a modification of the 3L linear solution developed by Lei et al and is more robust to noise and to coefficient quantization...