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Using the Fourier PSF plot

The Fourier PSF plot displays an image of the point-spread function (PSF) as calculated using the discrete Fourier transform (DFT).

To create the PSF plot window:

  1. Select from the menu Analysis > PSF > Fourier

Exporting data from PSF plot

The underlying data I(x,y) may be exported using the Export toolbar icon, or by "Save data as..." on the contextual menu (obtained by control clicking on the image).

Options panel

Field
Using the Field popup menu, select the field for which you wish to calculate. Select All to calculate for all fields (this can be very time-consuming).
Wave
Using the Wave popup menu, select the wave for which you wish to calculate. At present only the monochromatic diffraction OTF may be calculated.
Pupil sampling, number of rays per side
The pupil is sampled using a rectangular N by N grid of points that contains the pupil (if vignetting factors are zero). N is the "number of rays per side".
Interpolation order
To produce a smoother PSF or LSF, you can use this control to increase the order of Fourier interpolation used. The pupil data is Fourier transformed to produce the PSF, and this data is then (Fourier) interpolated to increase the resolution. The interpolation order is the number of doublings of the resolution.
Draw Airy disk
If checked, the Airy disk is drawn. n.b., this enables image resampling.
Draw rays
If checked, the geometrical rays are superimposed on the PSF image. n.b., this enables image resampling.
Resample image
Resamples image to center the pattern and make the image a specified minimum resolution, in case you wish to copy it out or save it.
False-color image
Colors instead of intensity shading.
Enhance faint features
Uses a nonlinear intensity map to amplify weak features.
Negative image
Reverse shading for high and low intensity.

See also