create_convolutionfunction_from_image

ska_sdp_datamodels.gridded_visibility.create_convolutionfunction_from_image(im, nw=1, wstep=1000000000000000.0, oversampling=8, support=16, polarisation_frame=None)[source]

Create a convolution function from an image

The convolution function has axes [chan, pol, z, dy, dx, y, x] where z, y, x are spatial axes in either sky or Fourier plane. The order in the WCS is reversed so the conv_func_WCS describes UU, VV, WW, STOKES, FREQ axes

The axes UU,VV have the same physical stride as the image. The axes DUU, DVV are sub-sampled.

Convolution function holds the original sky plane projection in the projection_wcs.

Parameters:

  • im – Template Image

  • nw – Number of z axes, usually z is W

  • wstep – Step in z, usually z is W

  • oversampling – Oversampling (size of dy, dx axes)

  • support – Support of final convolution function (size of y, x axes)

  • polarisation_frame – PolarisationFrame object

Returns:

Convolution Function