PixelatedDetector

PixelatedDetector#

class abtem.detectors.PixelatedDetector(max_angle='valid', resample=False, reciprocal_space=True, to_cpu=True, url=None)[source]#

Bases: BaseDetector

The pixelated detector records the intensity of the Fourier-transformed exit wave function, i.e. the diffraction patterns. This may be used for example for simulating 4D-STEM.

Parameters:

max_angle (float or {'cutoff', 'valid', 'full'}) –

The diffraction patterns will be detected up to this angle [mrad]. If str, it must be one of:

cutoff :
The maximum scattering angle will be the cutoff of the antialiasing aperture.

valid :
The maximum scattering angle will be the largest rectangle that fits inside the circular antialiasing aperture (default).

full :
Diffraction patterns will not be cropped and will include angles outside the antialiasing aperture.
resample (str or False) – If ‘uniform’, the diffraction patterns from rectangular cells will be downsampled to a uniform angular sampling.
reciprocal_space (bool, optional) – If True (default), the diffraction pattern intensities are detected, otherwise the probe intensities are detected as images.
to_cpu (bool, optional) – If True, copy the measurement data from the calculation device to CPU memory after applying the detector, otherwise the data stays on the respective devices. Default is True.
url (str, optional) – If this parameter is set the measurement data is saved at the specified location, typically a path to a local file. A URL can also include a protocol specifier like s3:// for remote data. If not set (default) the data stays in memory.

__init__(max_angle='valid', resample=False, reciprocal_space=True, to_cpu=True, url=None)[source]#

Methods

`__init__`([max_angle, resample, ...])
`angular_limits`(waves)	The outer limits of the detected scattering angles in x and y [mrad] for the given waves.
`apply`(array_object)	Apply the transform to the given waves.
`copy`()	Make a copy.
`detect`(waves)	Detect the given waves producing diffraction patterns.
`ensemble_blocks`([chunks])	Split the ensemble into an array of smaller ensembles.
`generate_blocks`([chunks])	Generate chunks of the ensemble.
`select_block`(index, chunks)	Select a block from the ensemble.

Attributes

`axes_metadata`	List of AxisMetadata.
`base_axes_metadata`	List of AxisMetadata of the base axes.
`base_shape`	Shape of the base axes.
`ensemble_axes_metadata`	Axes metadata describing the ensemble axes added to the waves when applying the transform.
`ensemble_shape`	The shape of the ensemble axes added to the waves when applying the transform.
`max_angle`	Maximum detected scattering angle.
`metadata`	Metadata added to the waves when applying the transform.
`reciprocal_space`	Detect the exit wave functions in real or reciprocal space.
`resample`	How to resample the detected diffraction patterns.
`shape`	Shape of the ensemble.
`to_cpu`	The measurements are copied to host memory.
`url`	The storage location of the measurement data.

angular_limits(waves)[source]#

The outer limits of the detected scattering angles in x and y [mrad] for the given waves.

Parameters:: waves (BaseWaves) – The waves to derive the detector limits from.
Returns:: limits
Return type:: tuple of float

apply(array_object)#

Apply the transform to the given waves.

Parameters:: array_object (ArrayObject) – The array object to transform.
Returns:: transformed_array_object
Return type:: ArrayObject

property axes_metadata: AxesMetadataList#: List of AxisMetadata.

property base_axes_metadata: list[AxisMetadata]#: List of AxisMetadata of the base axes.

property base_shape: tuple[int, ...]#: Shape of the base axes.

copy()#: Make a copy.

detect(waves)[source]#

Detect the given waves producing diffraction patterns.

Parameters:: waves (Waves) – The waves to detect.
Returns:: measurement
Return type:: DiffractionPatterns

property ensemble_axes_metadata: list[AxisMetadata]#: Axes metadata describing the ensemble axes added to the waves when applying the transform.

ensemble_blocks(chunks=None)#

Split the ensemble into an array of smaller ensembles.

Parameters:: chunks (iterable of tuples) – Block sizes along each dimension.
Return type:: Array

property ensemble_shape: tuple[int, ...]#: The shape of the ensemble axes added to the waves when applying the transform.

generate_blocks(chunks=1)#

Generate chunks of the ensemble.

Parameters:: chunks (iterable of tuples) – Block sizes along each dimension.

property max_angle: str | float#: Maximum detected scattering angle.

property metadata: dict#: Metadata added to the waves when applying the transform.

property reciprocal_space: bool#: Detect the exit wave functions in real or reciprocal space.

property resample: str | bool#: How to resample the detected diffraction patterns.

select_block(index, chunks)#

Select a block from the ensemble.

Parameters:

index (tuple of ints) – Index of selected block.
chunks (iterable of tuples) – Block sizes along each dimension.

property shape#: Shape of the ensemble.

property to_cpu#: The measurements are copied to host memory.

property url#: The storage location of the measurement data.

PixelatedDetector

Contents

PixelatedDetector#