apodization


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apodization

(ap-ŏ-di-zay -shŏn) Any process suppressing the secondary maxima of a diffraction pattern, such as the faint rings around the Airy disk of an optical image; this allows finer detail to be resolved. It may be achieved, for example, by progressively reducing the transmission of the telescope from the center of the aperture to its periphery.

apodization

[‚a·pə·də′zā·shən]
(electronics)
A technique for modifying the response of a surface acoustic wave filter by varying the overlap between adjacent electrodes of the interdigital transducer.
(optics)
The modification of the amplitude transmittance of the aperture of an optical system so as to reduce or suppress the energy of the diffraction rings relative to that of the central Airy disk.
(spectroscopy)
A mathematical transformation carried out on data received from an interferometer to alter the instrument's response function before the Fourier transformation is calculated to obtain the spectrum.
References in periodicals archive ?
Data were evaluated with Opus 6.5 software (Bruker Optics, Ettlingen, Germany) with Blackman Haris 3-Term apodization, in 4000-400 [cm.sup.-1] range with 64 scans at 4 [cm.sup.-1] resolution.
This aspheric IOL model has a 6.0 mm optic with a central zone of 3.6 mm apodization and outer refractive zone.
Each spectrum was obtained with triangle apodization using 64 scans in the range of 4000-400[cm.sup.-1], at a wavelength resolution of 4 [cm.sup.-1].
Ramping is usually accomplished by an apodization function such as a Tukey (tapered cosine) or a Hamming window, which smoothly reduces the intensity to zero.
Interferograms were Fourier transformed using cosine apodization for optimum linear response.
Another form of restricting it is by multiplying the function with a finite-support window function (apodization function) as stated by Thevenaz et al., (2000).
The spectra data was collected with twenty scans at a resolution of 4 [cm.sup.-1] and the apodization function was of the Happ-Genzel type.
A 0.3 Hz exponential apodization function was applied prior to Fourier transformation; then each spectrum was phase corrected (zero-order only) and stored in a vector of 131072 real points using the Topspin software (V2.5 PL 6, Bruker Biospin A.G., Rheinstetten, Germany).
The spectra were recorded using a Nexus Vector spectrometer (Nexus 670, Thermo Nicolet Company, USA) under the following specifications: Apodization: triangular; detector: DTGS/KBr; regulation: 4 [cm.sup.-1]; and number of scans: 32.
Hernandez, "Influence of spherical aberration, stimulus spatial frequency, and pupil apodization on subjective refractions," Ophthalmic & Physiological Optics, vol.
Zhu, "A novel flat-band long period grating with special apodization induced by high frequency C[O.sub.2] laser pulses," in Proceedings of the the Optical Fiber Communication Conference, Optical Society of America, Anaheim, CA, USA, 2006.
It is also due to the apodization function that we apply to the final image.