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 outcome parameters for screening of the cataract patients for suitability of multifocal intraocular lens evolved based on few aspects, such as, History taking, evaluating patient's personality profile, clinical and diagnostic evaluation and also it focuses on benefits of AcrySof diffractive IOL which has adopted apodisation technology.
Apodisation of central diffractive zone by gradually reducing the number of diffractive steps in width and height creates a smooth transition between far, intermediate and near focal points [27].
This gradual decrease in the apodisation of multifocal IOLs from center to the periphery in width and height allows a decrease in ocular operations, hence maximizing the lens performance.
Multi focal IOL has undergone various transformation, from refractive to diffractive apodisation and from +4 add to +3 add and +2.5 add.
Journal papers (He Cunfu, Li Ying, Wang Xiuyan, Wu Bin, Li Longtao, 2005) mentions the method wavelet transform and Wigner-Ville distribution which are also one of the popular methods of removing noise, but [WVD.sub.x] (t,[omega]) does not meet nonnegative demands that limit the application of Wigner-Ville distribution; In the final analysis Wavelet transform is still based on Fourier transform, so the selection of Apodisation function and the selection of wavelet base are the important factors that affect the effect.
In engineering, a signal is long, and we need an "instantaneous" Fourier Transform at each given time, thus a function that provides a time--window-termed apodisation function.
The recording was performed with a resolution of 4[cm.sup.-1], weak apodisation, and 16 scans per sample.