CONVOLVE

       Convolution of an image with a Point Spread Function (PSF)

       The default is to compute the convolution using a product of
       Fourier transforms (for speed).

       imconv = convolve( image1, psf, FT_PSF = psf_FT )
  or:
       correl = convolve( image1, image2, /CORREL )
  or:
       correl = convolve( image, /AUTO )

       image = 2-D array (matrix) to be convolved with psf
       psf = the Point Spread Function, (size < or = to size of image).

       FT_PSF = passes out/in the Fourier transform of the PSF,
               (so that it can be re-used the next time function is called).
       FT_IMAGE = passes out/in the Fourier transform of image.
       /CORRELATE uses the conjugate of the Fourier transform of PSF,
               to compute the cross-correlation of image and PSF,
               (equivalent to IDL function convol() with NO rotation of PSF)
       /AUTO_CORR computes the auto-correlation function of image using FFT.
       /NO_FT overrides the use of FFT, using IDL function convol() instead.
               (then PSF is rotated by 180 degrees to give same result)

       When using FFT, PSF is centered & expanded to size of image.

       written, Frank Varosi, NASA/GSFC 1992.
       Converted to IDL V5.0   W. Landsman   September 1997

[Home Page] [Software, Documentation] [IDL Documentation] [Quick Reference] [Feedback]