TukeyWindow

class photutils.psf_matching.TukeyWindow(alpha)

Bases: SplitCosineBellWindow

Class to define a 2D Tukey window function.

The Tukey window features a flat inner plateau equal to 1.0, surrounded by a smooth cosine taper that transitions to 0.0 at the edges. This provides an excellent balance between preserving data in the central region and suppressing edge artifacts.

The alpha parameter controls the trade-off: smaller values preserve more data but create stronger edge effects, while larger values reduce artifacts but taper more of the image.

Compared to HanningWindow, Tukey preserves a larger central region. Compared to TopHatWindow, it provides much better artifact suppression at the cost of tapering the outer regions.

Parameters:

alphafloat, optional

The percentage of array values that are tapered. Must be between 0.0 and 1.0, inclusive. When alpha=0, this becomes a TopHatWindow. When alpha=1, this becomes a HanningWindow.

Notes

Equivalent to SplitCosineBellWindow(alpha=alpha, beta=1.0 - alpha).

Examples

import matplotlib.pyplot as plt
from photutils.psf_matching import TukeyWindow

taper = TukeyWindow(alpha=0.4)
data = taper((101, 101))
fig, ax = plt.subplots()
axim = ax.imshow(data, origin='lower')
fig.colorbar(axim)

(Source code, png, hires.png, pdf, svg)

A 1D cut across the image center:

import matplotlib.pyplot as plt
from photutils.psf_matching import TukeyWindow

taper = TukeyWindow(alpha=0.4)
data = taper((101, 101))
fig, ax = plt.subplots()
ax.plot(data[50, :])

(Source code, png, hires.png, pdf, svg)

Methods Summary

__call__(shape)

Generate the window function for the given shape.

Methods Documentation

__call__(shape)

Generate the window function for the given shape.

Parameters:

shapetuple of int

The size of the output array along each axis.

Returns:

result2D ndarray

The window function as a 2D array.