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otf2psf

Convert optical transfer function to point-spread function

Syntax

PSF = otf2psf(OTF)
PSF = otf2psf(OTF, OUTSIZE)

Description

PSF = otf2psf(OTF) computes the inverse Fast Fourier Transform (IFFT) of the optical transfer function (OTF) array and creates a point-spread function (PSF), centered at the origin. By default, the PSF is the same size as the OTF.

PSF = otf2psf(OTF, OUTSIZE) converts the OTF array into a PSF array, where OUTSIZE specifies the size of the output point-spread function. The size of the output array must not exceed the size of the OTF array in any dimension.

To center the PSF at the origin, otf2psf circularly shifts the values of the output array down (or to the right) until the (1,1) element reaches the central position, then it crops the result to match dimensions specified by OUTSIZE.

Note that this function is used in image convolution/deconvolution when the operations involve the FFT.

Class Support

OTF can be any nonsparse, numeric array. PSF is of class double.

Examples

collapse all

Create a point-spread function (PSF).

PSF  = fspecial('gaussian',13,1);

Convert the PSF to an Optical Transfer Function (OTF).

OTF  = psf2otf(PSF,[31 31]);

Convert the OTF back to a PSF.

PSF2 = otf2psf(OTF,size(PSF));

Plot the PSF and the OTF.

subplot(1,2,1)
surf(abs(OTF))
title('|OTF|');
axis square
axis tight
subplot(1,2,2)
surf(PSF2)
title('Corresponding PSF');
axis square
axis tight

Introduced before R2006a

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