apodization


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apodization

(ap″ŏ-dĭ-zā′shŏn)
1. Alteration of a surface by removal of its irregularities.
2. Introduction of a gradual change into a mathematical function that would otherwise be discontinuous. It is used in radiology to smooth out choppy signals, and in optics, to blend diffractive steps.
References in periodicals archive ?
The new fast-aperture lens with an apodization filter is ideal for portrait with sublime focus effects.
During the process of scanning absorption spectra of the samples, Norton-Beer medium function is selected as the apodization function since it can lead to the best fitting adherence to Beer's law for the spectra measured at moderate resolution.
where P([theta]) is the pupil apodization function and [J.sub.n] is the nth order Bessel function of the first kind.
Typical methods include spatially variant apodization (SVA), super-SVA, and the CLEAN technique [19-22].
Notable means of suppressing sidebands in APD include apodization of the adiabatic pulses [9, 11], use of fractional initial decoupling periods [12], application of the SEAD pulse sequence [20], and matching the sweep rate and direction to the coupling [20].
The non- rectangular spectrum poses challenges for conventional sidelobe reduction (apodization) techniques [27-29].
In mathematics and in signal processing, a window function (also known as an apodization function or tapering function) is a mathematical function that is zero-valued outside of some chosen interval [13].
Choice of an apodization function form is most often determined by specific tasks of application, such as the achievement of the lowest level of the first side lobe of reflection (transmission) band (Figure 4(a), line 3), or the maximum suppression of peaks in the interval between adjacent Bragg reflection bands (Figure 4(a), line 2).
Rezig, "Broad antireflection grating by apodization of one dimensional photonic crystal," PIERS Proceedings, 1461-1464, Marrakesh, Morocco, Mar.
The measurement parameters were the following: spectral region 4000-400 [cm.sub.-1]; spectral resolution 8 [cm.sub.-1]; 128 scans; and Happ-Genzel apodization. Freshly dried KBr was used for the background measurement.
Apodization is applied during signal reception and transmission to improve the SNR by suitably shaping the Tx or Rx beam.