prtools.pixel_kernel#

pixel_kernel(shape, oversample=1, pixelscale=1.0, fftshift=False)[source]#

2D pixel MTF filter kernel

This function returns a normalized 2D sinc function sized to represent the transfer function of an idealized square pixel.

Parameters:

  • shape (int or tuple of int) – Shape of the kernel

  • oversample (float, optional) – Oversampling factor to represent in the kernel. Default is 1.

  • pixelscale (scalar or tuple of scalars, optional) – Sample spacing. Providing two values defines non-symmetric sampling interpreted as (pixelscale_row, pixelscale_col). Default is 1.

  • fftshift (bool, optional) – If True, the kernel is FFT-shifted so that the zero-frequency (DC) term is placed at the center of the returned array. Default is False.

Return type:

ndarray

See also

fftconv(), pixelate(), sinc()

Examples

>>> pixel_mtf = prtools.pixel_kernel((256,256), 1, fftshift=True)
>>> plt.imshow(pixel_mtf, cmap='gray', vmin=0)
../_images/prtools-pixel_kernel-1.png