ApertureMask¶
- class photutils.aperture.ApertureMask(data, bbox)[source]¶
Bases:
object
Class for an aperture mask.
- Parameters:
- dataarray_like
A 2D array representing the fractional overlap of an 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.aperture.BoundingBox
The bounding box object defining the aperture minimal bounding box.
Attributes Summary
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.
get_overlap_slices
(shape)Get slices for the overlapping part of the aperture mask and a 2D array.
get_values
(data[, mask])Get the mask-weighted pixel values from the data as a 1D array.
multiply
(data[, fill_value])Multiply the aperture mask with the input data, taking any edge effects into account.
to_image
(shape[, dtype])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:
- dataarray_like
A 2D array on which to apply the aperture mask.
- fill_valuefloat, optional
The value used to fill pixels where the aperture mask does not overlap with the input
data
. The default is 0.- copybool, optional
If
True
then the returned cutout array will always be hold a copy of the inputdata
. IfFalse
and the mask is fully within the inputdata
, then the returned cutout array will be a view into the inputdata
. In cases where the mask partially overlaps or has no overlap with the inputdata
, the returned cutout array will always hold a copy of the inputdata
(i.e., this keyword has no effect).
- Returns:
- result
ndarray
orNone
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 tofill_value
.None
is returned if there is no overlap of the aperture with the inputdata
.
- result
- get_overlap_slices(shape)[source]¶
Get slices for the overlapping part of the aperture mask and a 2D array.
- Parameters:
- shape2-tuple of int
The shape of the 2D array.
- Returns:
- slices_largetuple of slices or
None
A tuple of slice objects for each axis of the large array, such that
large_array[slices_large]
extracts the region of the large array that overlaps with the small array.None
is returned if there is no overlap of the bounding box with the given image shape.- slices_smalltuple of slices or
None
A tuple of slice objects for each axis of the aperture mask array such that
small_array[slices_small]
extracts the region that is inside the large array.None
is returned if there is no overlap of the bounding box with the given image shape.
- slices_largetuple of slices or
- get_values(data, mask=None)[source]¶
Get the mask-weighted pixel values from the data as a 1D array.
If the
ApertureMask
was created withmethod='center'
, (where the mask weights are only 1 or 0), then the returned values will simply be pixel values extracted from the data.- Parameters:
- Returns:
- result
ndarray
A 1D array of mask-weighted pixel values from the input
data
. If there is no overlap of the aperture with the inputdata
, the result will be an empty array with shape (0,).
- result
- 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:
- dataarray_like or
Quantity
The 2D array to multiply with the aperture mask.
- fill_valuefloat, optional
The value is used to fill pixels where the aperture mask does not overlap with the input
data
. The default is 0.
- dataarray_like or
- Returns:
- result
ndarray
orNone
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 tofill_value
before being multiplied with the mask.None
is returned if there is no overlap of the aperture with the inputdata
.
- result
- to_image(shape, dtype=<class 'float'>)[source]¶
Return an image of the mask in a 2D array of the given shape, taking any edge effects into account.
- Parameters:
- shapetuple of int
The
(ny, nx)
shape of the output array.- dtypedata-type, optional
The desired data type for the array. This should be a floating data type if the
ApertureMask
was created with the “exact” or “subpixel” mode, otherwise the fractional mask weights will be altered. A integer data type may be used if theApertureMask
was created with the “center” mode.
- Returns:
- result
ndarray
A 2D array of the mask.
- result