PSFTOLSF Convert a line spread function to a point spread function
lsf = PSFTOLSF(psf,varargin)
This works by convolving a horizontal line with a psf and returning the vertical slice through the center. The spatial support of the lsf is equal to the spatial support of the vertical slice through the passed psf. The passed psf should be square. The returned lsf is normalized to have a peak amplitude of 1. See also LSFTOPSF.