1.1.1.0 image.fft

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image.fft - Function

1.1.1 FFT the image
Description

This function fast Fourier Transforms the image to the Fourier plane. If you leave axes unset, then the sky plane of the image (if there is one) is transformed. Otherwise, you can specify which axes you wish to transform. Note that if you specify a sky axis, you must specify both of them.

You specify which form you wish to see the result in by specifying the desired output image file name(s). At some point, an output complex image will also be allowed (when the Image tool can deal with it).

Before the FFT is taken, any masked pixels are replaced by zero. The output mask is the combination (logical OR) of the default input pixel mask (if any) and the OTF mask. Any other input pixel masks will not be copied. Use function maskhandler if you need to copy other masks too.

Arguments


Inputs
real	Output real image file name
	allowed:	string
	Default:
imag	Output imaginary image file name
	allowed:	string
	Default:
amp	Output amplitude image file name
	allowed:	string
	Default:
phase	Output phase image file name
	allowed:	string
	Default:
axes	Specify pixel axes to FFT. Default is sky plane(s).
	allowed:	intArray
	Default:	-1
region	The region of interest. Default is whole image.
	allowed:	any
	Default:	record
mask	OTF mask, Boolean LEL expression or mask region. Default is none.
	allowed:	any
	Default:	variant

Returns
bool

Example

"""
#
print "\t----\t fft Ex 1 \t----"
ia.maketestimage(’gc.small’, overwrite=true)
ia.fft(real=’r.im’, amp=’a.im’)
ia.close()
ia.removefile(’r.im’) # clean up example ouptut files
ia.removefile(’a.im’)
#
"""

This transforms only the sky plane(s). The real and amplitude images only are written out.

Example

"""
#
print "\t----\t fft Ex 2 \t----"
ia.fromshape(’gc.small’, [64,64,128], overwrite=true)
ia.fft(amp=’amp.im’, phase=’p.im’, axes=[2])
ia.close()
ia.removefile(’amp.im’) # clean up example output files
ia.removefile(’p.im’)
#
"""

This transforms only the third axis of the image. The amplitude and phase images only are written out.

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