fftserver.shift - Function

Shift an array a non-integral number of pixels.

Synopsis
shift(a, shift)

Arguments

a		Real array
shift		How much to shift on each axis. > 0 means towards the end of the array, < 0 means towards the beginning of the array.

Returns
Real array

Description

The units of the shift, which need not be integral, are pixels. The length of shift must be the same as the number of dimensions of a. So, if a is a 1-dimensional array, then shift is a scalar.

This function shifts an array by; Fourier transforming it, multiplying each element of the transform by a complex phase factor, inverse Fourier transforming the result.

Multiplication by a linear phase gradient in the spectral domain corresponds to a shift in the image domain, so this process will shift the original array. If the shift is a non-integral number of pixels then a band-limited, or sinc interpolation is done.

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	Package	utility
	Module	mathematics
	Tool	fftserver