ApertureMask

class photutils.ApertureMask(data, bbox)[source]

Bases: object

Class for an aperture mask.

Parameters:
mask : array_like

A 2D array of an aperture mask representing the fractional overlap of the aperture on the pixel grid. This should be the full-sized (i.e. not truncated) array that is the direct output of one of the low-level photutils.geometry functions.

bbox : photutils.BoundingBox

The bounding box object defining the aperture minimal bounding box.

Attributes Summary

shape The shape of the mask data array.

Methods Summary

cutout(data[, fill_value, copy]) Create a cutout from the input data over the mask bounding box, taking any edge effects into account.
multiply(data[, fill_value]) Multiply the aperture mask with the input data, taking any edge effects into account.
to_image(shape) Return an image of the mask in a 2D array of the given shape, taking any edge effects into account.

Attributes Documentation

shape

The shape of the mask data array.

Methods Documentation

cutout(data, fill_value=0.0, copy=False)[source]

Create a cutout from the input data over the mask bounding box, taking any edge effects into account.

Parameters:
data : array_like

A 2D array on which to apply the aperture mask.

fill_value : float, optional

The value is used to fill pixels where the aperture mask does not overlap with the input data. The default is 0.

copy : bool, optional

If True then the returned cutout array will always be hold a copy of the input data. If False and the mask is fully within the input data, then the returned cutout array will be a view into the input data. In cases where the mask partially overlaps or has no overlap with the input data, the returned cutout array will always hold a copy of the input data (i.e. this keyword has no effect).

Returns:
result : ndarray

A 2D array cut out from the input data representing the same cutout region as the aperture mask. If there is a partial overlap of the aperture mask with the input data, pixels outside of the data will be assigned to fill_value. None is returned if there is no overlap of the aperture with the input data.

multiply(data, fill_value=0.0)[source]

Multiply the aperture mask with the input data, taking any edge effects into account.

The result is a mask-weighted cutout from the data.

Parameters:
data : array_like or Quantity

The 2D array to multiply with the aperture mask.

fill_value : float, optional

The value is used to fill pixels where the aperture mask does not overlap with the input data. The default is 0.

Returns:
result : ndarray

A 2D mask-weighted cutout from the input data. If there is a partial overlap of the aperture mask with the input data, pixels outside of the data will be assigned to fill_value before being multipled with the mask. None is returned if there is no overlap of the aperture with the input data.

to_image(shape)[source]

Return an image of the mask in a 2D array of the given shape, taking any edge effects into account.

Parameters:
shape : tuple of int

The (ny, nx) shape of the output array.

Returns:
result : ndarray

A 2D array of the mask.