hyperspy.signal module¶

class
hyperspy.signal.
BaseSetMetadataItems
(signal)¶ Bases:
traits.has_traits.HasTraits

class
hyperspy.signal.
BaseSignal
(data, **kwds)¶ Bases:
hyperspy.misc.slicing.FancySlicing
,hyperspy.learn.mva.MVA
,hyperspy.signal.MVATools
Create a Signal from a numpy array.
 Parameters
data (
numpy.ndarray
) – The signal data. It can be an array of any dimensions.axes (dict, optional) – Dictionary to define the axes (see the documentation of the
AxesManager
class for more details).attributes (dict, optional) – A dictionary whose items are stored as attributes.
metadata (dict, optional) – A dictionary containing a set of parameters that will to stores in the
metadata
attribute. Some parameters might be mandatory in some cases.original_metadata (dict, optional) – A dictionary containing a set of parameters that will to stores in the
original_metadata
attribute. It typically contains all the parameters that has been imported from the original data file.

property
T
¶ The transpose of the signal, with signal and navigation spaces swapped. Enables calling
transpose()
with the default parameters as a property of a Signal.
Check the shape of the navigation mask.
 Parameters
mask (numpy array or BaseSignal.) – Mask to check the shape.
 Raises
ValueError – If shape doesn’t match the shape of the navigation dimension.
 Returns
 Return type
None.

_check_signal_mask
(mask)¶ Check the shape of the signal mask.
 Parameters
mask (numpy array or BaseSignal.) – Mask to check the shape.
 Raises
ValueError – If shape doesn’t match the shape of the signal dimension.
 Returns
 Return type
None.

_cycle_signal
()¶ Cycles over the signal data.
It is faster than using the signal iterator.
Warning! could produce a infinite loop.

property
_data_aligned_with_axes
¶ Returns a view of data with is axes aligned with the Signal axes.

_deepcopy_with_new_data
(data=None, copy_variance=False, copy_navigator=False, copy_learning_results=False)¶ Returns a deepcopy of itself replacing the data.
This method has an advantage over the default
copy.deepcopy()
in that it does not copy the data, which can save memory. Parameters
data (None or
numpy.ndarray
) –copy_variance (bool) – Whether to copy the variance of the signal to the new copy
copy_navigator (bool) – Whether to copy the navigator of the signal to the new copy
copy_learning_results (bool) – Whether to copy the learning_results of the signal to the new copy
 Returns
ns – The newly copied signal
 Return type
BaseSignal
(or subclass)
Return a signal with the same axes as the navigation space.
 Parameters
data (None or
numpy.ndarray
, optional) – IfNone
, the resulting Signal data is an array of the same dtype as the current one filled with zeros. If a numpy array, the array must have the correct dimensions.dtype (
numpy.dtype
, optional) – The desired datatype for the data array when data isNone
, e.g.,numpy.int8
. The default is the data type of the current signal data.

_get_signal_signal
(data=None, dtype=None)¶ Return a signal with the same axes as the signal space.
 Parameters
data (None or
numpy.ndarray
, optional) – IfNone
, the resulting Signal data is an array of the same dtype as the current one filled with zeros. If a numpy array, the array must have the correct dimensions.dtype (
numpy.dtype
, optional) – The desired datatype for the data array when data isNone
, e.g.,numpy.int8
. The default is the data type of the current signal data.

_iterate_signal
()¶ Iterates over the signal data.
It is faster than using the signal iterator.

_load_dictionary
(file_data_dict)¶ Load data from dictionary.
 Parameters
file_data_dict (dict) –
A dictionary containing at least a ‘data’ keyword with an array of arbitrary dimensions. Additionally the dictionary can contain the following items:
data: the signal data. It can be an array of any dimensions.
axes: a dictionary to define the axes (see the documentation of the
AxesManager
class for more details).attributes: a dictionary whose items are stored as attributes.
metadata: a dictionary containing a set of parameters that will to stores in the metadata attribute. Some parameters might be mandatory in some cases.
original_metadata: a dictionary containing a set of parameters that will to stores in the original_metadata attribute. It typically contains all the parameters that has been imported from the original data file.

_map_all
(function, inplace=True, **kwargs)¶ The function has to have either ‘axis’ or ‘axes’ keyword argument, and hence support operating on the full dataset efficiently.
Replaced for lazy signals

_map_iterate
(function, iterating_kwargs=(), show_progressbar=None, parallel=None, max_workers=None, ragged=None, inplace=True, **kwargs)¶ Iterates the signal navigation space applying the function.
 Parameters
function (function) – the function to apply
iterating_kwargs (tuple (of tuples)) – A tuple with structure ((‘key1’, value1), (‘key2’, value2), ..) where the keyvalue pairs will be passed as kwargs for the function to be mapped, and the values will be iterated together with the signal navigation. The value needs to be a signal instance because passing array can be ambigous and will be removed in HyperSpy 2.0.
show_progressbar (None or bool) – If
True
, display a progress bar. IfNone
, the default from the preferences settings is used.parallel (None or bool) – If
True
, perform computation in parallel using multithreading. IfNone
, the default from the preferences settings is used. The number of threads is controlled by themax_workers
argument.max_workers (None or int) – Maximum number of threads used when
parallel=True
. If None, defaults tomin(32, os.cpu_count())
.inplace (bool, default True) – if
True
, the data is replaced by the result. Otherwise a new signal with the results is returned.ragged (None or bool, default None) – Indicates if results for each navigation pixel are of identical shape (and/or numpy arrays to begin with). If
None
, an appropriate choice is made while processing. Note:None
is not allowed for Lazy signals!**kwargs (dict) – Additional keyword arguments passed to function
Notes
This method is replaced for lazy signals.
Examples
Pass a larger array of different shape
>>> s = hs.signals.Signal1D(np.arange(20.).reshape((20,1))) >>> def func(data, value=0): ... return data + value >>> # pay attention that it's a tuple of tuples  need commas >>> s._map_iterate(func, ... iterating_kwargs=(('value', ... np.random.rand(5,400).flat),)) >>> s.data.T array([[ 0.82869603, 1.04961735, 2.21513949, 3.61329091, 4.2481755 , 5.81184375, 6.47696867, 7.07682618, 8.16850697, 9.37771809, 10.42794054, 11.24362699, 12.11434077, 13.98654036, 14.72864184, 15.30855499, 16.96854373, 17.65077064, 18.64925703, 19.16901297]])
Storing function result to other signal (e.g. calculated shifts)
>>> s = hs.signals.Signal1D(np.arange(20.).reshape((5,4))) >>> def func(data): # the original function ... return data.sum() >>> result = s._get_navigation_signal().T >>> def wrapped(*args, data=None): ... return func(data) >>> result._map_iterate(wrapped, ... iterating_kwargs=(('data', s),)) >>> result.data array([ 6., 22., 38., 54., 70.])

_to_dictionary
(add_learning_results=True, add_models=False, add_original_metadata=True)¶ Returns a dictionary that can be used to recreate the signal.
All items but data are copies.
 Parameters
add_learning_results (bool, optional) – Whether or not to include any multivariate learning results in the outputted dictionary. Default is True.
add_models (bool, optional) – Whether or not to include any models in the outputted dictionary. Default is False
add_original_metadata (bool) – Whether or not to include the original_medata in the outputted dictionary. Default is True.
 Returns
dic – The dictionary that can be used to recreate the signal
 Return type

_unfold
(steady_axes, unfolded_axis)¶ Modify the shape of the data by specifying the axes whose dimension do not change and the axis over which the remaining axes will be unfolded
 Parameters
See also
Notes
WARNING: this private function does not modify the signal subclass and it is intended for internal use only. To unfold use the public
unfold()
,unfold_navigation_space()
,unfold_signal_space()
instead. It doesn’t make sense to perform an unfolding when dim < 2

add_gaussian_noise
(std, random_state=None)¶ Add Gaussian noise to the data.
The operation is performed inplace (i.e. the data of the signal is modified). This method requires the signal to have a float data type, otherwise it will raise a
TypeError
. Parameters
Note
This method uses
numpy.random.normal()
(ordask.array.random.normal()
for lazy signals) to generate the noise.

add_marker
(marker, plot_on_signal=True, plot_marker=True, permanent=False, plot_signal=True, render_figure=True)¶ Add one or several markers to the signal or navigator plot and plot the signal, if not yet plotted (by default)
 Parameters
marker (
hyperspy.drawing.marker
object or iterable) – The marker or iterable (list, tuple, …) of markers to add. See the Markers section in the User Guide if you want to add a large number of markers as an iterable, since this will be much faster. For signals with navigation dimensions, the markers can be made to change for different navigation indices. See the examples for info.plot_on_signal (bool) – If
True
(default), add the marker to the signal. IfFalse
, add the marker to the navigatorplot_marker (bool) – If
True
(default), plot the marker.permanent (bool) – If
False
(default), the marker will only appear in the current plot. IfTrue
, the marker will be added to the metadata.Markers list, and be plotted withplot(plot_markers=True)
. If the signal is saved as a HyperSpy HDF5 file, the markers will be stored in the HDF5 signal and be restored when the file is loaded.
Examples
>>> import scipy.misc >>> im = hs.signals.Signal2D(scipy.misc.ascent()) >>> m = hs.markers.rectangle(x1=150, y1=100, x2=400, >>> y2=400, color='red') >>> im.add_marker(m)
Adding to a 1D signal, where the point will change when the navigation index is changed:
>>> s = hs.signals.Signal1D(np.random.random((3, 100))) >>> marker = hs.markers.point((19, 10, 60), (0.2, 0.5, 0.9)) >>> s.add_marker(marker, permanent=True, plot_marker=True)
Add permanent marker:
>>> s = hs.signals.Signal2D(np.random.random((100, 100))) >>> marker = hs.markers.point(50, 60, color='red') >>> s.add_marker(marker, permanent=True, plot_marker=True)
Add permanent marker to signal with 2 navigation dimensions. The signal has navigation dimensions (3, 2), as the dimensions gets flipped compared to the output from
numpy.random.random()
. To add a vertical line marker which changes for different navigation indices, the list used to make the marker must be a nested list: 2 lists with 3 elements each (2 x 3):>>> s = hs.signals.Signal1D(np.random.random((2, 3, 10))) >>> marker = hs.markers.vertical_line([[1, 3, 5], [2, 4, 6]]) >>> s.add_marker(marker, permanent=True)
Add permanent marker which changes with navigation position, and do not add it to a current plot:
>>> s = hs.signals.Signal2D(np.random.randint(10, size=(3, 100, 100))) >>> marker = hs.markers.point((10, 30, 50), (30, 50, 60), color='red') >>> s.add_marker(marker, permanent=True, plot_marker=False) >>> s.plot(plot_markers=True)
Removing a permanent marker:
>>> s = hs.signals.Signal2D(np.random.randint(10, size=(100, 100))) >>> marker = hs.markers.point(10, 60, color='red') >>> marker.name = "point_marker" >>> s.add_marker(marker, permanent=True) >>> del s.metadata.Markers.point_marker
Adding many markers as a list:
>>> from numpy.random import random >>> s = hs.signals.Signal2D(np.random.randint(10, size=(100, 100))) >>> marker_list = [] >>> for i in range(100): >>> marker = hs.markers.point(random()*100, random()*100, color='red') >>> marker_list.append(marker) >>> s.add_marker(marker_list, permanent=True)

add_poissonian_noise
(keep_dtype=True, random_state=None)¶ Add Poissonian noise to the data.
This method works inplace. The resulting data type is
int64
. If this is different from the original data type then a warning is added to the log. Parameters
keep_dtype (bool, default True) – If
True
, keep the original data type of the signal data. For example, if the data type was initially'float64'
, the result of the operation (usually'int64'
) will be converted to'float64'
.random_state (None or int or RandomState instance, default None) – Seed for the random generator.
Note
This method uses
numpy.random.poisson()
(ordask.array.random.poisson()
for lazy signals) to generate the Poissonian noise.

apply_apodization
(window='hann', hann_order=None, tukey_alpha=0.5, inplace=False)¶ Apply an apodization window to a Signal.
 Parameters
window (str, optional) – Select between {
'hann'
(default),'hamming'
, or'tukey'
}hann_order (None or int, optional) – Only used if
window='hann'
If integer n is provided, a Hann window of nth order will be used. IfNone
, a first order Hann window is used. Higher orders result in more homogeneous intensity distribution.tukey_alpha (float, optional) –
Only used if
window='tukey'
(default is 0.5). From the documentation ofscipy.signal.windows.tukey()
:Shape parameter of the Tukey window, representing the fraction of the window inside the cosine tapered region. If zero, the Tukey window is equivalent to a rectangular window. If one, the Tukey window is equivalent to a Hann window.
inplace (bool, optional) – If
True
, the apodization is applied in place, i.e. the signal data will be substituted by the apodized one (default isFalse
).
 Returns
out – If
inplace=False
, returns the apodized signal of the same type as the provided Signal. Return type
BaseSignal
(or subclasses), optional
Examples
>>> import hyperspy.api as hs >>> holo = hs.datasets.example_signals.object_hologram() >>> holo.apply_apodization('tukey', tukey_alpha=0.1).plot()

as_lazy
(copy_variance=True, copy_navigator=True, copy_learning_results=True)¶ Create a copy of the given Signal as a
LazySignal
. Parameters
copy_variance (bool) – Whether or not to copy the variance from the original Signal to the new lazy version. Default is True.
copy_navigator (bool) – Whether or not to copy the navigator from the original Signal to the new lazy version. Default is True.
copy_learning_results (bool) – Whether to copy the learning_results from the original signal to the new lazy version. Default is True.
 Returns
res – The same signal, converted to be lazy
 Return type

as_signal1D
(spectral_axis, out=None, optimize=True)¶ Return the Signal as a spectrum.
The chosen spectral axis is moved to the last index in the array and the data is made contiguous for efficient iteration over spectra. By default, the method ensures the data is stored optimally, hence often making a copy of the data. See
transpose()
for a more general method with more options. Parameters
spectral_axis (
int
,str
, orDataAxis
) – The axis can be passed directly, or specified using the index of the axis in the Signal’s axes_manager or the axis name.out (
BaseSignal
(or subclasses) orNone
) – IfNone
, a new Signal is created with the result of the operation and returned (default). If a Signal is passed, it is used to receive the output of the operation, and nothing is returned.optimize (bool) – If
True
, the location of the data in memory is optimised for the fastest iteration over the navigation axes. This operation can cause a peak of memory usage and requires considerable processing times for large datasets and/or low specification hardware. See the Transposing (changing signal spaces) section of the HyperSpy user guide for more information. When operating on lazy signals, ifTrue
, the chunks are optimised for the new axes configuration.
Examples
>>> img = hs.signals.Signal2D(np.ones((3,4,5,6))) >>> img <Signal2D, title: , dimensions: (4, 3, 6, 5)> >>> img.as_signal1D(1+1j) <Signal1D, title: , dimensions: (6, 5, 4, 3)> >>> img.as_signal1D(0) <Signal1D, title: , dimensions: (6, 5, 3, 4)>

as_signal2D
(image_axes, out=None, optimize=True)¶ Convert a signal to image (
Signal2D
).The chosen image axes are moved to the last indices in the array and the data is made contiguous for efficient iteration over images.
 Parameters
image_axes (tuple (of int, str or
DataAxis
)) – Select the image axes. Note that the order of the axes matters and it is given in the “natural” i.e. X, Y, Z… order.out (
BaseSignal
(or subclasses) orNone
) – IfNone
, a new Signal is created with the result of the operation and returned (default). If a Signal is passed, it is used to receive the output of the operation, and nothing is returned.optimize (bool) – If
True
, the location of the data in memory is optimised for the fastest iteration over the navigation axes. This operation can cause a peak of memory usage and requires considerable processing times for large datasets and/or low specification hardware. See the Transposing (changing signal spaces) section of the HyperSpy user guide for more information. When operating on lazy signals, ifTrue
, the chunks are optimised for the new axes configuration.
 Raises
DataDimensionError – When data.ndim < 2
Examples
>>> s = hs.signals.Signal1D(np.ones((2,3,4,5))) >>> s <Signal1D, title: , dimensions: (4, 3, 2, 5)> >>> s.as_signal2D((0,1)) <Signal2D, title: , dimensions: (5, 2, 4, 3)>
>>> s.to_signal2D((1,2)) <Signal2D, title: , dimensions: (4, 5, 3, 2)>

change_dtype
(dtype, rechunk=True)¶ Change the data type of a Signal.
 Parameters
dtype (str or
numpy.dtype
) – Typecode string or datatype to which the Signal’s data array is cast. In addition to all the standard numpy Data type objects (dtype), HyperSpy supports four extra dtypes for RGB images:'rgb8'
,'rgba8'
,'rgb16'
, and'rgba16'
. Changing from and to anyrgb(a)
dtype is more constrained than most other dtype conversions. To change to anrgb(a)
dtype, the signal_dimension must be 1, and its size should be 3 (forrgb
) or 4 (forrgba
) dtypes. The original dtype should beuint8
oruint16
if converting torgb(a)8
orrgb(a))16
, and the navigation_dimension should be at least 2. After conversion, the signal_dimension becomes 2. The dtype of images with original dtypergb(a)8
orrgb(a)16
can only be changed touint8
oruint16
, and the signal_dimension becomes 1.rechunk (bool) – Only has effect when operating on lazy signal. If
True
(default), the data may be automatically rechunked before performing this operation.
Examples
>>> s = hs.signals.Signal1D([1,2,3,4,5]) >>> s.data array([1, 2, 3, 4, 5]) >>> s.change_dtype('float') >>> s.data array([ 1., 2., 3., 4., 5.])

copy
()¶ Return a “shallow copy” of this Signal using the standard library’s
copy()
function. Note: this will return a copy of the signal, but it will not duplicate the underlying data in memory, and both Signals will reference the same data.See also

crop
(axis, start=None, end=None, convert_units=False)¶ Crops the data in a given axis. The range is given in pixels.
 Parameters
axis (int or str) – Specify the data axis in which to perform the cropping operation. The axis can be specified using the index of the axis in axes_manager or the axis name.
start (int, float, or None) – The beginning of the cropping interval. If type is
int
, the value is taken as the axis index. If type isfloat
the index is calculated using the axis calibration. If start/end isNone
the method crops from/to the low/high end of the axis.end (int, float, or None) – The end of the cropping interval. If type is
int
, the value is taken as the axis index. If type isfloat
the index is calculated using the axis calibration. If start/end isNone
the method crops from/to the low/high end of the axis.convert_units (bool) – Default is
False
. IfTrue
, convert the units using theconvert_units()
method of theAxesManager
. IfFalse
, does nothing.

property
data
¶ The underlying data structure as a
numpy.ndarray
(ordask.array.Array
, if the Signal is lazy).

deepcopy
()¶ Return a “deep copy” of this Signal using the standard library’s
deepcopy()
function. Note: this means the underlying data structure will be duplicated in memory.See also

derivative
(axis, order=1, out=None, rechunk=True)¶ Calculate the numerical derivative along the given axis, with respect to the calibrated units of that axis.
For a function y = f(x) and two consecutive values x_1 and x_2:
\frac{df(x)}{dx} = \frac{y(x_2)y(x_1)}{x_2x_1}
 Parameters
axis (
int
,str
, orDataAxis
) – The axis can be passed directly, or specified using the index of the axis in the Signal’s axes_manager or the axis name.order (int) – The order of the derivative.
out (
BaseSignal
(or subclasses) orNone
) – IfNone
, a new Signal is created with the result of the operation and returned (default). If a Signal is passed, it is used to receive the output of the operation, and nothing is returned.rechunk (bool) – Only has effect when operating on lazy signal. If
True
(default), the data may be automatically rechunked before performing this operation.
 Returns
der – Note that the size of the data on the given
axis
decreases by the givenorder
. i.e. ifaxis
is"x"
andorder
is 2, if the x dimension is N, thender
’s x dimension is N  2. Return type
See also

diff
(axis, order=1, out=None, rechunk=True)¶ Returns a signal with the nth order discrete difference along given axis. i.e. it calculates the difference between consecutive values in the given axis: out[n] = a[n+1]  a[n]. See
numpy.diff()
for more details. Parameters
axis (
int
,str
, orDataAxis
) – The axis can be passed directly, or specified using the index of the axis in the Signal’s axes_manager or the axis name.order (int) – The order of the discrete difference.
out (
BaseSignal
(or subclasses) orNone
) – IfNone
, a new Signal is created with the result of the operation and returned (default). If a Signal is passed, it is used to receive the output of the operation, and nothing is returned.rechunk (bool) – Only has effect when operating on lazy signal. If
True
(default), the data may be automatically rechunked before performing this operation.
 Returns
s – Note that the size of the data on the given
axis
decreases by the givenorder
. i.e. ifaxis
is"x"
andorder
is 2, the x dimension is N,der
’s x dimension is N  2. Return type
BaseSignal
(or subclasses) or None
See also
Examples
>>> import numpy as np >>> s = BaseSignal(np.random.random((64,64,1024))) >>> s.data.shape (64,64,1024) >>> s.diff(1).data.shape (64,64,1023)

estimate_poissonian_noise_variance
(expected_value=None, gain_factor=None, gain_offset=None, correlation_factor=None)¶ Estimate the Poissonian noise variance of the signal.
The variance is stored in the metadata.Signal.Noise_properties.variance attribute.
The Poissonian noise variance is equal to the expected value. With the default arguments, this method simply sets the variance attribute to the given expected_value. However, more generally (although then the noise is not strictly Poissonian), the variance may be proportional to the expected value. Moreover, when the noise is a mixture of white (Gaussian) and Poissonian noise, the variance is described by the following linear model:
\mathrm{Var}[X] = (a * \mathrm{E}[X] + b) * c
Where a is the gain_factor, b is the gain_offset (the Gaussian noise variance) and c the correlation_factor. The correlation factor accounts for correlation of adjacent signal elements that can be modeled as a convolution with a Gaussian point spread function.
 Parameters
expected_value (
None
orBaseSignal
(or subclasses)) – IfNone
, the signal data is taken as the expected value. Note that this may be inaccurate where the value of data is small.gain_factor (None or float) – a in the above equation. Must be positive. If
None
, take the value from metadata.Signal.Noise_properties.Variance_linear_model if defined. Otherwise, suppose pure Poissonian noise (i.e.gain_factor=1
). If notNone
, the value is stored in metadata.Signal.Noise_properties.Variance_linear_model.gain_offset (None or float) – b in the above equation. Must be positive. If
None
, take the value from metadata.Signal.Noise_properties.Variance_linear_model if defined. Otherwise, suppose pure Poissonian noise (i.e.gain_offset=0
). If notNone
, the value is stored in metadata.Signal.Noise_properties.Variance_linear_model.correlation_factor (None or float) – c in the above equation. Must be positive. If
None
, take the value from metadata.Signal.Noise_properties.Variance_linear_model if defined. Otherwise, suppose pure Poissonian noise (i.e.correlation_factor=1
). If notNone
, the value is stored in metadata.Signal.Noise_properties.Variance_linear_model.

fft
(shift=False, apodization=False, real_fft_only=False, **kwargs)¶ Compute the discrete Fourier Transform.
This function computes the discrete Fourier Transform over the signal axes by means of the Fast Fourier Transform (FFT) as implemented in numpy.
 Parameters
shift (bool, optional) – If
True
, the origin of FFT will be shifted to the centre (default isFalse
).Apply an apodization window before calculating the FFT in order to suppress streaks. Valid string values are {
'hann'
or'hamming'
or'tukey'
} IfTrue
or'hann'
, applies a Hann window. If'hamming'
or'tukey'
, applies Hamming or Tukey windows, respectively (default isFalse
).real_fft_only (bool, default False) – If
True
and data is realvalued, usesnumpy.fft.rfftn()
instead ofnumpy.fft.fftn()
**kwargs (dict) – other keyword arguments are described in
numpy.fft.fftn()
 Returns
s – A Signal containing the result of the FFT algorithm
 Return type
Examples
>>> im = hs.signals.Signal2D(scipy.misc.ascent()) >>> im.fft() <ComplexSignal2D, title: FFT of , dimensions: (512, 512)>
>>> # Use following to plot power spectrum of `im`: >>> im.fft(shift=True, apodization=True).plot(power_spectrum=True)
Note
For further information see the documentation of
numpy.fft.fftn()

fold
()¶ If the signal was previously unfolded, fold it back

get_current_signal
(auto_title=True, auto_filename=True)¶ Returns the data at the current coordinates as a
BaseSignal
subclass.The signal subclass is the same as that of the current object. All the axes navigation attributes are set to
False
. Parameters
auto_title (bool) – If
True
, the current indices (in parentheses) are appended to the title, separated by a space.auto_filename (bool) – If
True
and tmp_parameters.filename is defined (which is always the case when the Signal has been read from a file), the filename stored in the metadata is modified by appending an underscore and the current indices in parentheses.
 Returns
cs – The data at the current coordinates as a Signal
 Return type
BaseSignal
(or subclass)
Examples
>>> im = hs.signals.Signal2D(np.zeros((2,3, 32,32))) >>> im <Signal2D, title: , dimensions: (3, 2, 32, 32)> >>> im.axes_manager.indices = 2,1 >>> im.get_current_signal() <Signal2D, title: (2, 1), dimensions: (32, 32)>

get_dimensions_from_data
()¶ Get the dimension parameters from the Signal’s underlying data. Useful when the data structure was externally modified, or when the spectrum image was not loaded from a file

get_histogram
(bins='fd', range_bins=None, max_num_bins=250, out=None, **kwargs)¶ Return a histogram of the signal data.
More sophisticated algorithms for determining the bins can be used by passing a string as the
bins
argument. Other than the'blocks'
and'knuth'
methods, the available algorithms are the same asnumpy.histogram()
.Note: The lazy version of the algorithm only supports
"scott"
and"fd"
as a string argument forbins
. Parameters
bins (int or sequence of scalars or str, default "fd") –
If bins is an int, it defines the number of equalwidth bins in the given range. If bins is a sequence, it defines the bin edges, including the rightmost edge, allowing for nonuniform bin widths.
If bins is a string from the list below, will use the method chosen to calculate the optimal bin width and consequently the number of bins (see Notes for more detail on the estimators) from the data that falls within the requested range. While the bin width will be optimal for the actual data in the range, the number of bins will be computed to fill the entire range, including the empty portions. For visualisation, using the ‘auto’ option is suggested. Weighted data is not supported for automated bin size selection.
 ’auto’
Maximum of the ‘sturges’ and ‘fd’ estimators. Provides good all around performance.
 ’fd’ (Freedman Diaconis Estimator)
Robust (resilient to outliers) estimator that takes into account data variability and data size.
 ’doane’
An improved version of Sturges’ estimator that works better with nonnormal datasets.
 ’scott’
Less robust estimator that that takes into account data variability and data size.
 ’stone’
Estimator based on leaveoneout crossvalidation estimate of the integrated squared error. Can be regarded as a generalization of Scott’s rule.
 ’rice’
Estimator does not take variability into account, only data size. Commonly overestimates number of bins required.
 ’sturges’
R’s default method, only accounts for data size. Only optimal for gaussian data and underestimates number of bins for large nongaussian datasets.
 ’sqrt’
Square root (of data size) estimator, used by Excel and other programs for its speed and simplicity.
 ’knuth’
Knuth’s rule is a fixedwidth, Bayesian approach to determining the optimal bin width of a histogram.
 ’blocks’
Determination of optimal adaptivewidth histogram bins using the Bayesian Blocks algorithm.
range_bins (tuple or None, optional) – the minimum and maximum range for the histogram. If range_bins is
None
, (x.min()
,x.max()
) will be used.max_num_bins (int, default 250) – When estimating the bins using one of the str methods, the number of bins is capped by this number to avoid a MemoryError being raised by
numpy.histogram()
.out (
BaseSignal
(or subclasses) orNone
) – IfNone
, a new Signal is created with the result of the operation and returned (default). If a Signal is passed, it is used to receive the output of the operation, and nothing is returned.rechunk (bool) – Only has effect when operating on lazy signal. If
True
(default), the data may be automatically rechunked before performing this operation.**kwargs – other keyword arguments (weight and density) are described in
numpy.histogram()
.
 Returns
hist_spec – A 1D spectrum instance containing the histogram.
 Return type
See also
print_summary_statistics
dask.histogram()
Examples
>>> s = hs.signals.Signal1D(np.random.normal(size=(10, 100))) >>> # Plot the data histogram >>> s.get_histogram().plot() >>> # Plot the histogram of the signal at the current coordinates >>> s.get_current_signal().get_histogram().plot()

get_noise_variance
()¶ Get the noise variance of the signal, if set.
Equivalent to
s.metadata.Signal.Noise_properties.variance
. Parameters
None –
 Returns
variance – Noise variance of the signal, if set. Otherwise returns None.
 Return type
None or float or
BaseSignal
(or subclasses)

ifft
(shift=None, return_real=True, **kwargs)¶ Compute the inverse discrete Fourier Transform.
This function computes the real part of the inverse of the discrete Fourier Transform over the signal axes by means of the Fast Fourier Transform (FFT) as implemented in numpy.
 Parameters
shift (bool or None, optional) – If
None
, the shift option will be set to the original status of the FFT using the value in metadata. If no FFT entry is present in metadata, the parameter will be set toFalse
. IfTrue
, the origin of the FFT will be shifted to the centre. IfFalse
, the origin will be kept at (0, 0) (default isNone
).return_real (bool, default True) – If
True
, returns only the real part of the inverse FFT. IfFalse
, returns all parts.**kwargs (dict) – other keyword arguments are described in
numpy.fft.ifftn()
 Returns
s – A Signal containing the result of the inverse FFT algorithm
 Return type
BaseSignal
(or subclasses)
Examples
>>> import scipy >>> im = hs.signals.Signal2D(scipy.misc.ascent()) >>> imfft = im.fft() >>> imfft.ifft() <Signal2D, title: real(iFFT of FFT of ), dimensions: (512, 512)>
Note
For further information see the documentation of
numpy.fft.ifftn()

indexmax
(axis, out=None, rechunk=True)¶ Returns a signal with the index of the maximum along an axis.
 Parameters
axis (
int
,str
, orDataAxis
) – The axis can be passed directly, or specified using the index of the axis in the Signal’s axes_manager or the axis name.out (
BaseSignal
(or subclasses) orNone
) – IfNone
, a new Signal is created with the result of the operation and returned (default). If a Signal is passed, it is used to receive the output of the operation, and nothing is returned.rechunk (bool) – Only has effect when operating on lazy signal. If
True
(default), the data may be automatically rechunked before performing this operation.
 Returns
s – A new Signal containing the indices of the maximum along the specified axis. Note: the data dtype is always
int
. Return type
BaseSignal
(or subclasses)
See also
max()
,min()
,sum()
,mean()
,std()
,var()
,indexmin()
,valuemax()
,valuemin()
Examples
>>> import numpy as np >>> s = BaseSignal(np.random.random((64,64,1024))) >>> s.data.shape (64,64,1024) >>> s.indexmax(1).data.shape (64,64)

indexmin
(axis, out=None, rechunk=True)¶ Returns a signal with the index of the minimum along an axis.
 Parameters
axis (
int
,str
, orDataAxis
) – The axis can be passed directly, or specified using the index of the axis in the Signal’s axes_manager or the axis name.out (
BaseSignal
(or subclasses) orNone
) – IfNone
, a new Signal is created with the result of the operation and returned (default). If a Signal is passed, it is used to receive the output of the operation, and nothing is returned.rechunk (bool) – Only has effect when operating on lazy signal. If
True
(default), the data may be automatically rechunked before performing this operation.
 Returns
s – A new Signal containing the indices of the minimum along the specified axis. Note: the data dtype is always
int
. Return type
BaseSignal
(or subclasses)
See also
max()
,min()
,sum()
,mean()
,std()
,var()
,indexmax()
,valuemax()
,valuemin()
Examples
>>> import numpy as np >>> s = BaseSignal(np.random.random((64,64,1024))) >>> s.data.shape (64,64,1024) >>> s.indexmin(1).data.shape (64,64)

integrate1D
(axis, out=None)¶ Integrate the signal over the given axis.
The integration is performed using Simpson’s rule if metadata.Signal.binned is
False
and simple summation over the given axis ifTrue
. Parameters
axis (
int
,str
, orDataAxis
) – The axis can be passed directly, or specified using the index of the axis in the Signal’s axes_manager or the axis name.out (
BaseSignal
(or subclasses) orNone
) – IfNone
, a new Signal is created with the result of the operation and returned (default). If a Signal is passed, it is used to receive the output of the operation, and nothing is returned.
 Returns
s – A new Signal containing the integral of the provided Signal along the specified axis.
 Return type
BaseSignal
(or subclasses)
See also
Examples
>>> import numpy as np >>> s = BaseSignal(np.random.random((64,64,1024))) >>> s.data.shape (64,64,1024) >>> s.integrate1D(1).data.shape (64,64)

integrate_simpson
(axis, out=None)¶ Calculate the integral of a Signal along an axis using Simpson’s rule.
 Parameters
axis (
int
,str
, orDataAxis
) – The axis can be passed directly, or specified using the index of the axis in the Signal’s axes_manager or the axis name.out (
BaseSignal
(or subclasses) orNone
) – IfNone
, a new Signal is created with the result of the operation and returned (default). If a Signal is passed, it is used to receive the output of the operation, and nothing is returned.
 Returns
s – A new Signal containing the integral of the provided Signal along the specified axis.
 Return type
BaseSignal
(or subclasses)
See also
Examples
>>> import numpy as np >>> s = BaseSignal(np.random.random((64,64,1024))) >>> s.data.shape (64,64,1024) >>> s.integrate_simpson(1).data.shape (64,64)

property
is_rgb
¶ Whether or not this signal is an RGB dtype.

property
is_rgba
¶ Whether or not this signal is an RGB + alpha channel dtype.

property
is_rgbx
¶ Whether or not this signal is either an RGB or RGB + alpha channel dtype.

map
(function, show_progressbar=None, parallel=None, max_workers=None, inplace=True, ragged=None, output_signal_size=None, output_dtype=None, **kwargs)¶ Apply a function to the signal data at all the navigation coordinates.
The function must operate on numpy arrays. It is applied to the data at each navigation coordinate pixelpypixel. Any extra keyword arguments are passed to the function. The keywords can take different values at different coordinates. If the function takes an axis or axes argument, the function is assumed to be vectorized and the signal axes are assigned to axis or axes. Otherwise, the signal is iterated over the navigation axes and a progress bar is displayed to monitor the progress.
In general, only navigation axes (order, calibration, and number) are guaranteed to be preserved.
 Parameters
function (function) – Any function that can be applied to the signal.
show_progressbar (None or bool) – If
True
, display a progress bar. IfNone
, the default from the preferences settings is used.parallel (None or bool) – If
True
, perform computation in parallel using multithreading. IfNone
, the default from the preferences settings is used. The number of threads is controlled by themax_workers
argument.max_workers (None or int) – Maximum number of threads used when
parallel=True
. If None, defaults tomin(32, os.cpu_count())
.inplace (bool, default True) – if
True
, the data is replaced by the result. Otherwise a new Signal with the results is returned.ragged (None or bool, default None) – Indicates if the results for each navigation pixel are of identical shape (and/or numpy arrays to begin with). If
None
, the appropriate choice is made while processing. If True in case of lazy signal, the signal will be compute at the end of the mapping. Note:None
is not allowed for Lazy signals!**kwargs (dict) – All extra keyword arguments are passed to the provided function
Notes
If the function results do not have identical shapes, the result is an array of navigation shape, where each element corresponds to the result of the function (of arbitrary object type), called a “ragged array”. As such, most functions are not able to operate on the result and the data should be used directly.
This method is similar to Python’s
map()
that can also be utilized with aBaseSignal
instance for similar purposes. However, this method has the advantage of being faster because it iterates the underlying numpy data array instead of theBaseSignal
.Examples
Apply a Gaussian filter to all the images in the dataset. The sigma parameter is constant:
>>> import scipy.ndimage >>> im = hs.signals.Signal2D(np.random.random((10, 64, 64))) >>> im.map(scipy.ndimage.gaussian_filter, sigma=2.5)
Apply a Gaussian filter to all the images in the dataset. The signal parameter is variable:
>>> im = hs.signals.Signal2D(np.random.random((10, 64, 64))) >>> sigmas = hs.signals.BaseSignal(np.linspace(2,5,10)).T >>> im.map(scipy.ndimage.gaussian_filter, sigma=sigmas)

max
(axis=None, out=None, rechunk=True)¶ Returns a signal with the maximum of the signal along at least one axis.
 Parameters
axis (
int
,str
,DataAxis
, tuple (of DataAxis) orNone
) – Either one on its own, or many axes in a tuple can be passed. In both cases the axes can be passed directly, or specified using the index in axes_manager or the name of the axis. Any duplicates are removed. IfNone
, the operation is performed over all navigation axes (default).out (
BaseSignal
(or subclasses) orNone
) – IfNone
, a new Signal is created with the result of the operation and returned (default). If a Signal is passed, it is used to receive the output of the operation, and nothing is returned.rechunk (bool) – Only has effect when operating on lazy signal. If
True
(default), the data may be automatically rechunked before performing this operation.
 Returns
s – A new Signal containing the maximum of the provided Signal over the specified axes
 Return type
BaseSignal
(or subclasses)
See also
min()
,sum()
,mean()
,std()
,var()
,indexmax()
,indexmin()
,valuemax()
,valuemin()
Examples
>>> import numpy as np >>> s = BaseSignal(np.random.random((64,64,1024))) >>> s.data.shape (64,64,1024) >>> s.max(1).data.shape (64,64)

mean
(axis=None, out=None, rechunk=True)¶ Returns a signal with the average of the signal along at least one axis.
 Parameters
axis (
int
,str
,DataAxis
, tuple (of DataAxis) orNone
) – Either one on its own, or many axes in a tuple can be passed. In both cases the axes can be passed directly, or specified using the index in axes_manager or the name of the axis. Any duplicates are removed. IfNone
, the operation is performed over all navigation axes (default).out (
BaseSignal
(or subclasses) orNone
) – IfNone
, a new Signal is created with the result of the operation and returned (default). If a Signal is passed, it is used to receive the output of the operation, and nothing is returned.rechunk (bool) – Only has effect when operating on lazy signal. If
True
(default), the data may be automatically rechunked before performing this operation.
 Returns
s – A new Signal containing the mean of the provided Signal over the specified axes
 Return type
BaseSignal
(or subclasses)
See also
max()
,min()
,sum()
,std()
,var()
,indexmax()
,indexmin()
,valuemax()
,valuemin()
Examples
>>> import numpy as np >>> s = BaseSignal(np.random.random((64,64,1024))) >>> s.data.shape (64,64,1024) >>> s.mean(1).data.shape (64,64)

min
(axis=None, out=None, rechunk=True)¶ Returns a signal with the minimum of the signal along at least one axis.
 Parameters
axis (
int
,str
,DataAxis
, tuple (of DataAxis) orNone
) – Either one on its own, or many axes in a tuple can be passed. In both cases the axes can be passed directly, or specified using the index in axes_manager or the name of the axis. Any duplicates are removed. IfNone
, the operation is performed over all navigation axes (default).out (
BaseSignal
(or subclasses) orNone
) – IfNone
, a new Signal is created with the result of the operation and returned (default). If a Signal is passed, it is used to receive the output of the operation, and nothing is returned.rechunk (bool) – Only has effect when operating on lazy signal. If
True
(default), the data may be automatically rechunked before performing this operation.
 Returns
s – A new Signal containing the minimum of the provided Signal over the specified axes
 Return type
BaseSignal
(or subclasses)
See also
max()
,sum()
,mean()
,std()
,var()
,indexmax()
,indexmin()
,valuemax()
,valuemin()
Examples
>>> import numpy as np >>> s = BaseSignal(np.random.random((64,64,1024))) >>> s.data.shape (64,64,1024) >>> s.min(1).data.shape (64,64)

nanmax
(axis=None, out=None, rechunk=True)¶ Identical to
max()
, except ignores missing (NaN) values. See that method’s documentation for details.

nanmean
(axis=None, out=None, rechunk=True)¶ Identical to
mean()
, except ignores missing (NaN) values. See that method’s documentation for details.

nanmin
(axis=None, out=None, rechunk=True)¶ Identical to
min()
, except ignores missing (NaN) values. See that method’s documentation for details.

nanstd
(axis=None, out=None, rechunk=True)¶ Identical to
std()
, except ignores missing (NaN) values. See that method’s documentation for details.

nansum
(axis=None, out=None, rechunk=True)¶ Identical to
sum()
, except ignores missing (NaN) values. See that method’s documentation for details.

nanvar
(axis=None, out=None, rechunk=True)¶ Identical to
var()
, except ignores missing (NaN) values. See that method’s documentation for details.

plot
(navigator='auto', axes_manager=None, plot_markers=True, **kwargs)¶ Plot the signal at the current coordinates.
For multidimensional datasets an optional figure, the “navigator”, with a cursor to navigate that data is raised. In any case it is possible to navigate the data using the sliders. Currently only signals with signal_dimension equal to 0, 1 and 2 can be plotted.
 Parameters
navigator (str, None, or
BaseSignal
(or subclass). Allowed string values are'auto'
,'slider'
, and'spectrum'
.) –If
'auto'
:If navigation_dimension > 0, a navigator is provided to explore the data.
If navigation_dimension is 1 and the signal is an image the navigator is a sum spectrum obtained by integrating over the signal axes (the image).
If navigation_dimension is 1 and the signal is a spectrum the navigator is an image obtained by stacking all the spectra in the dataset horizontally.
If navigation_dimension is > 1, the navigator is a sum image obtained by integrating the data over the signal axes.
Additionally, if navigation_dimension > 2, a window with one slider per axis is raised to navigate the data.
For example, if the dataset consists of 3 navigation axes X, Y, Z and one signal axis, E, the default navigator will be an image obtained by integrating the data over E at the current Z index and a window with sliders for the X, Y, and Z axes will be raised. Notice that changing the Zaxis index changes the navigator in this case.
For lazy signals, the navigator will be calculated using the
compute_navigator()
method.
If
'slider'
:If navigation dimension > 0 a window with one slider per axis is raised to navigate the data.
If
'spectrum'
:If navigation_dimension > 0 the navigator is always a spectrum obtained by integrating the data over all other axes.
Not supported for lazy signals, the
'auto'
option will be used instead.
If
None
, no navigator will be provided.Alternatively a
BaseSignal
(or subclass) instance can be provided. The navigation or signal shape must match the navigation shape of the signal to plot or the navigation_shape + signal_shape must be equal to the navigator_shape of the current object (for a dynamic navigator). If the signal dtype is RGB or RGBA this parameter has no effect and the value is always set to'slider'
.axes_manager (None or
AxesManager
) – If None, the signal’s axes_manager attribute is used.plot_markers (bool, default True) – Plot markers added using s.add_marker(marker, permanent=True). Note, a large number of markers might lead to very slow plotting.
navigator_kwds (dict) – Only for image navigator, additional keyword arguments for
matplotlib.pyplot.imshow()
.norm (str, optional) – The function used to normalize the data prior to plotting. Allowable strings are:
'auto'
,'linear'
,'log'
. (default value is'auto'
). If'auto'
, intensity is plotted on a linear scale except whenpower_spectrum=True
(only for complex signals).autoscale (str) – The string must contain any combination of the ‘x’ and ‘v’ characters. If ‘x’ or ‘v’ (for values) are in the string, the corresponding horizontal or vertical axis limits are set to their maxima and the axis limits will reset when the data or the navigation indices are changed. Default is ‘v’.
**kwargs (dict) – Only when plotting an image: additional (optional) keyword arguments for
matplotlib.pyplot.imshow()
.

print_summary_statistics
(formatter='%.3g', rechunk=True)¶ Prints the fivenumber summary statistics of the data, the mean, and the standard deviation.
Prints the mean, standard deviation (std), maximum (max), minimum (min), first quartile (Q1), median, and third quartile. nans are removed from the calculations.
 Parameters
See also

rebin
(new_shape=None, scale=None, crop=True, out=None)¶ Rebin the signal into a smaller or larger shape, based on linear interpolation. Specify either new_shape or scale.
 Parameters
new_shape (list (of floats or integer) or None) – For each dimension specify the new_shape. This will internally be converted into a scale parameter.
scale (list (of floats or integer) or None) – For each dimension, specify the new:old pixel ratio, e.g. a ratio of 1 is no binning and a ratio of 2 means that each pixel in the new spectrum is twice the size of the pixels in the old spectrum. The length of the list should match the dimension of the Signal’s underlying data array. Note : Only one of `scale` or `new_shape` should be specified, otherwise the function will not run
crop (bool) –
Whether or not to crop the resulting rebinned data (default is
True
). When binning by a noninteger number of pixels it is likely that the final row in each dimension will contain fewer than the full quota to fill one pixel.e.g. a 5*5 array binned by 2.1 will produce two rows containing 2.1 pixels and one row containing only 0.8 pixels. Selection of
crop=True
orcrop=False
determines whether or not this “black” line is cropped from the final binned array or not.
Please note that if
crop=False
is used, the final row in each dimension may appear black if a fractional number of pixels are left over. It can be removed but has been left to preserve total counts before and after binning.out (
BaseSignal
(or subclasses) orNone
) – IfNone
, a new Signal is created with the result of the operation and returned (default). If a Signal is passed, it is used to receive the output of the operation, and nothing is returned.
 Returns
s – The resulting cropped signal.
 Return type
BaseSignal
(or subclass)
Examples
>>> spectrum = hs.signals.EDSTEMSpectrum(np.ones([4, 4, 10])) >>> spectrum.data[1, 2, 9] = 5 >>> print(spectrum) <EDXTEMSpectrum, title: dimensions: (4, 410)> >>> print ('Sum = ', sum(sum(sum(spectrum.data)))) Sum = 164.0 >>> scale = [2, 2, 5] >>> test = spectrum.rebin(scale) >>> print(test) <EDSTEMSpectrum, title: dimensions (2, 22)> >>> print('Sum = ', sum(sum(sum(test.data)))) Sum = 164.0

rollaxis
(axis, to_axis, optimize=False)¶ Roll the specified axis backwards, until it lies in a given position.
 Parameters
axis (
int
,str
, orDataAxis
) – The axis can be passed directly, or specified using the index of the axis in the Signal’s axes_manager or the axis name. The axis to roll backwards. The positions of the other axes do not change relative to one another.to_axis (
int
,str
, orDataAxis
) – The axis can be passed directly, or specified using the index of the axis in the Signal’s axes_manager or the axis name. The axis is rolled until it lies before this other axis.optimize (bool) – If
True
, the location of the data in memory is optimised for the fastest iteration over the navigation axes. This operation can cause a peak of memory usage and requires considerable processing times for large datasets and/or low specification hardware. See the Transposing (changing signal spaces) section of the HyperSpy user guide for more information. When operating on lazy signals, ifTrue
, the chunks are optimised for the new axes configuration.
 Returns
s – Output signal.
 Return type
BaseSignal
(or subclass)
See also
Examples
>>> s = hs.signals.Signal1D(np.ones((5,4,3,6))) >>> s <Signal1D, title: , dimensions: (3, 4, 5, 6)> >>> s.rollaxis(3, 1) <Signal1D, title: , dimensions: (3, 4, 5, 6)> >>> s.rollaxis(2,0) <Signal1D, title: , dimensions: (5, 3, 4, 6)>

save
(filename=None, overwrite=None, extension=None, **kwds)¶ Saves the signal in the specified format.
The function gets the format from the specified extension (see Supported formats in the User Guide for more information):
'hspy'
for HyperSpy’s HDF5 specification'rpl'
for Ripple (useful to export to Digital Micrograph)'msa'
for EMSA/MSA single spectrum saving.'unf'
for SEMPER unf binary format.'blo'
for Blockfile diffraction stack saving.Many image formats such as
'png'
,'tiff'
,'jpeg'
…
If no extension is provided the default file format as defined in the preferences is used. Please note that not all the formats supports saving datasets of arbitrary dimensions, e.g.
'msa'
only supports 1D data, and blockfiles only supports image stacks with a navigation_dimension < 2.Each format accepts a different set of parameters. For details see the specific format documentation.
 Parameters
filename (str or None) – If None (default) and tmp_parameters.filename and tmp_parameters.folder are defined, the filename and path will be taken from there. A valid extension can be provided e.g.
'my_file.rpl'
(see extension parameter).overwrite (None or bool) – If None, if the file exists it will query the user. If True(False) it does(not) overwrite the file if it exists.
The extension of the file that defines the file format. Allowable string values are: {
'hspy'
,'hdf5'
,'rpl'
,'msa'
,'unf'
,'blo'
,'emd'
, and common image extensions e.g.'tiff'
,'png'
, etc.}'hspy'
and'hdf5'
are equivalent. Use'hdf5'
if compatibility with HyperSpy versions older than 1.2 is required. IfNone
, the extension is determined from the following list in this order:the filename
Signal.tmp_parameters.extension
'hspy'
(the default extension)
chunks (tuple or True or None (default)) – HyperSpy, Nexus and EMD NCEM format only. Define chunks used when saving. The chunk shape should follow the order of the array (
s.data.shape
), not the shape of theaxes_manager
. If None and lazy signal, the dask array chunking is used. If None and nonlazy signal, the chunks are estimated automatically to have at least one chunk per signal space. If True, the chunking is determined by the the h5pyguess_chunk
function.save_original_metadata (bool , default : False) – Nexus file only. Option to save hyperspy.original_metadata with the signal. A loaded Nexus file may have a large amount of data when loaded which you may wish to omit on saving
use_default (bool , default : False) – Nexus file only. Define the default dataset in the file. If set to True the signal or first signal in the list of signals will be defined as the default (following Nexus v3 data rules).

set_noise_variance
(variance)¶ Set the noise variance of the signal.
Equivalent to
s.metadata.set_item("Signal.Noise_properties.variance", variance)
. Parameters
variance (None or float or
BaseSignal
(or subclasses)) – Value or values of the noise variance. A value of None is equivalent to clearing the variance. Returns
 Return type

set_signal_origin
(origin)¶ Set the signal_origin metadata value.
The signal_origin attribute specifies if the data was obtained through experiment or simulation.
 Parameters
origin (str) – Typically
'experiment'
or'simulation'

set_signal_type
(signal_type='')¶ Set the signal type and convert the current signal accordingly.
The
signal_type
attribute specifies the type of data that the signal contains e.g. electron energyloss spectroscopy data, photoemission spectroscopy data, etc.When setting signal_type to a “known” type, HyperSpy converts the current signal to the most appropriate
hyperspy.signal.BaseSignal
subclass. Known signal types are signal types that have a specializedhyperspy.signal.BaseSignal
subclass associated, usually providing specific features for the analysis of that type of signal.HyperSpy ships with a minimal set of known signal types. External packages can register extra signal types. To print a list of registered signal types in the current installation, call
hyperspy.utils.print_known_signal_types()
, and see the developer guide for details on how to add new signal_types. A nonexhaustive list of HyperSpy extensions is also maintained here: https://github.com/hyperspy/hyperspyextensionslist. Parameters
signal_type (str, optional) – If no arguments are passed, the
signal_type
is set to undefined and the current signal converted to a generic signal subclass. Otherwise, set the signal_type to the given signal type or to the signal type corresponding to the given signal type alias. Setting the signal_type to a known signal type (if exists) is highly advisable. If none exists, it is good practice to set signal_type to a value that best describes the data signal type.
Examples
Let’s first print all known signal types:
>>> s = hs.signals.Signal1D([0, 1, 2, 3]) >>> s <Signal1D, title: , dimensions: (4)> >>> hs.print_known_signal_types() +++++  signal_type  aliases  class name  package  +++++  DielectricFunction  dielectric function  DielectricFunction  hyperspy   EDS_SEM   EDSSEMSpectrum  hyperspy   EDS_TEM   EDSTEMSpectrum  hyperspy   EELS  TEM EELS  EELSSpectrum  hyperspy   hologram   HologramImage  hyperspy   MySignal   MySignal  hspy_ext  +++++
We can set the signal_type using the signal_type:
>>> s.set_signal_type("EELS") >>> s <EELSSpectrum, title: , dimensions: (4)> >>> s.set_signal_type("EDS_SEM") >>> s <EDSSEMSpectrum, title: , dimensions: (4)>
or any of its aliases:
>>> s.set_signal_type("TEM EELS") >>> s <EELSSpectrum, title: , dimensions: (4)>
To set the signal_type to undefined, simply call the method without arguments:
>>> s.set_signal_type() >>> s <Signal1D, title: , dimensions: (4)>

split
(axis='auto', number_of_parts='auto', step_sizes='auto')¶ Splits the data into several signals.
The split can be defined by giving the number_of_parts, a homogeneous step size, or a list of customized step sizes. By default (
'auto'
), the function is the reverse ofstack()
. Parameters
axis (
int
,str
, orDataAxis
) – The axis can be passed directly, or specified using the index of the axis in the Signal’s axes_manager or the axis name. If'auto'
and if the object has been created withstack()
(andstack_metadata=True
), this method will return the former list of signals (information stored in metadata._HyperSpy.Stacking_history). If it was not created withstack()
, the last navigation axis will be used.number_of_parts (str or int) – Number of parts in which the spectrum image will be split. The splitting is homogeneous. When the axis size is not divisible by the number_of_parts the remainder data is lost without warning. If number_of_parts and step_sizes is
'auto'
, number_of_parts equals the length of the axis, step_sizes equals one, and the axis is suppressed from each subspectrum.step_sizes (str, list (of ints), or int) – Size of the split parts. If
'auto'
, the step_sizes equals one. If an int is given, the splitting is homogeneous.
Examples
>>> s = hs.signals.Signal1D(random.random([4,3,2])) >>> s <Signal1D, title: , dimensions: (3, 42)> >>> s.split() [<Signal1D, title: , dimensions: (3 2)>, <Signal1D, title: , dimensions: (3 2)>, <Signal1D, title: , dimensions: (3 2)>, <Signal1D, title: , dimensions: (3 2)>] >>> s.split(step_sizes=2) [<Signal1D, title: , dimensions: (3, 22)>, <Signal1D, title: , dimensions: (3, 22)>] >>> s.split(step_sizes=[1,2]) [<Signal1D, title: , dimensions: (3, 12)>, <Signal1D, title: , dimensions: (3, 22)>]
 Returns
splitted – A list of the split signals
 Return type

squeeze
()¶ Remove singledimensional entries from the shape of an array and the axes. See
numpy.squeeze()
for more details. Returns
s – A new signal object with singleentry dimensions removed
 Return type
signal
Examples
>>> s = hs.signals.Signal2D(np.random.random((2,1,1,6,8,8))) <Signal2D, title: , dimensions: (6, 1, 1, 28, 8)> >>> s = s.squeeze() >>> s <Signal2D, title: , dimensions: (6, 28, 8)>

std
(axis=None, out=None, rechunk=True)¶ Returns a signal with the standard deviation of the signal along at least one axis.
 Parameters
axis (
int
,str
,DataAxis
, tuple (of DataAxis) orNone
) – Either one on its own, or many axes in a tuple can be passed. In both cases the axes can be passed directly, or specified using the index in axes_manager or the name of the axis. Any duplicates are removed. IfNone
, the operation is performed over all navigation axes (default).out (
BaseSignal
(or subclasses) orNone
) – IfNone
, a new Signal is created with the result of the operation and returned (default). If a Signal is passed, it is used to receive the output of the operation, and nothing is returned.rechunk (bool) – Only has effect when operating on lazy signal. If
True
(default), the data may be automatically rechunked before performing this operation.
 Returns
s – A new Signal containing the standard deviation of the provided Signal over the specified axes
 Return type
BaseSignal
(or subclasses)
See also
max()
,min()
,sum()
,mean()
,var()
,indexmax()
,indexmin()
,valuemax()
,valuemin()
Examples
>>> import numpy as np >>> s = BaseSignal(np.random.random((64,64,1024))) >>> s.data.shape (64,64,1024) >>> s.std(1).data.shape (64,64)

sum
(axis=None, out=None, rechunk=True)¶ Sum the data over the given axes.
 Parameters
axis (
int
,str
,DataAxis
, tuple (of DataAxis) orNone
) – Either one on its own, or many axes in a tuple can be passed. In both cases the axes can be passed directly, or specified using the index in axes_manager or the name of the axis. Any duplicates are removed. IfNone
, the operation is performed over all navigation axes (default).out (
BaseSignal
(or subclasses) orNone
) – IfNone
, a new Signal is created with the result of the operation and returned (default). If a Signal is passed, it is used to receive the output of the operation, and nothing is returned.rechunk (bool) – Only has effect when operating on lazy signal. If
True
(default), the data may be automatically rechunked before performing this operation.
 Returns
s – A new Signal containing the sum of the provided Signal along the specified axes.
 Return type
BaseSignal
(or subclasses)
See also
max()
,min()
,mean()
,std()
,var()
,indexmax()
,indexmin()
,valuemax()
,valuemin()
Examples
>>> import numpy as np >>> s = BaseSignal(np.random.random((64,64,1024))) >>> s.data.shape (64,64,1024) >>> s.sum(1).data.shape (64,64)

swap_axes
(axis1, axis2, optimize=False)¶ Swap two axes in the signal.
 Parameters
axis1 (
int
,str
, orDataAxis
) – The axis can be passed directly, or specified using the index of the axis in the Signal’s axes_manager or the axis name.axis2 (
int
,str
, orDataAxis
) – The axis can be passed directly, or specified using the index of the axis in the Signal’s axes_manager or the axis name.optimize (bool) – If
True
, the location of the data in memory is optimised for the fastest iteration over the navigation axes. This operation can cause a peak of memory usage and requires considerable processing times for large datasets and/or low specification hardware. See the Transposing (changing signal spaces) section of the HyperSpy user guide for more information. When operating on lazy signals, ifTrue
, the chunks are optimised for the new axes configuration.
 Returns
s – A copy of the object with the axes swapped.
 Return type
BaseSignal
(or subclass)
See also

transpose
(signal_axes=None, navigation_axes=None, optimize=False)¶ Transposes the signal to have the required signal and navigation axes.
 Parameters
signal_axes (None, int, or iterable type) – The number (or indices) of axes to convert to signal axes
navigation_axes (None, int, or iterable type) – The number (or indices) of axes to convert to navigation axes
optimize (bool) – If
True
, the location of the data in memory is optimised for the fastest iteration over the navigation axes. This operation can cause a peak of memory usage and requires considerable processing times for large datasets and/or low specification hardware. See the Transposing (changing signal spaces) section of the HyperSpy user guide for more information. When operating on lazy signals, ifTrue
, the chunks are optimised for the new axes configuration.
Note
With the exception of both axes parameters (signal_axes and navigation_axes getting iterables, generally one has to be
None
(i.e. “floating”). The other one specifies either the required number or explicitly the indices of axes to move to the corresponding space. If both are iterables, full control is given as long as all axes are assigned to one space only.See also
T()
,as_signal2D()
,as_signal1D()
,hyperspy.misc.utils.transpose()
Examples
>>> # just create a signal with many distinct dimensions >>> s = hs.signals.BaseSignal(np.random.rand(1,2,3,4,5,6,7,8,9)) >>> s <BaseSignal, title: , dimensions: (9, 8, 7, 6, 5, 4, 3, 2, 1)>
>>> s.transpose() # swap signal and navigation spaces <BaseSignal, title: , dimensions: (9, 8, 7, 6, 5, 4, 3, 2, 1)>
>>> s.T # a shortcut for no arguments <BaseSignal, title: , dimensions: (9, 8, 7, 6, 5, 4, 3, 2, 1)>
>>> # roll to leave 5 axes in navigation space >>> s.transpose(signal_axes=5) <BaseSignal, title: , dimensions: (4, 3, 2, 19, 8, 7, 6, 5)>
>>> # roll leave 3 axes in navigation space >>> s.transpose(navigation_axes=3) <BaseSignal, title: , dimensions: (3, 2, 19, 8, 7, 6, 5, 4)>
>>> # 3 explicitly defined axes in signal space >>> s.transpose(signal_axes=[0, 2, 6]) <BaseSignal, title: , dimensions: (8, 6, 5, 4, 2, 19, 7, 3)>
>>> # A mix of two lists, but specifying all axes explicitly >>> # The order of axes is preserved in both lists >>> s.transpose(navigation_axes=[1, 2, 3, 4, 5, 8], signal_axes=[0, 6, 7]) <BaseSignal, title: , dimensions: (8, 7, 6, 5, 4, 19, 3, 2)>

unfold
(unfold_navigation=True, unfold_signal=True)¶ Modifies the shape of the data by unfolding the signal and navigation dimensions separately
 Parameters
 Returns
needed_unfolding – Whether or not one of the axes needed unfolding (and that unfolding was performed)
 Return type
Note
It doesn’t make sense to perform an unfolding when the total number of dimensions is < 2.
Modify the shape of the data to obtain a navigation space of dimension 1
 Returns
needed_unfolding – Whether or not the navigation space needed unfolding (and whether it was performed)
 Return type

unfold_signal_space
()¶ Modify the shape of the data to obtain a signal space of dimension 1
 Returns
needed_unfolding – Whether or not the signal space needed unfolding (and whether it was performed)
 Return type

unfolded
(unfold_navigation=True, unfold_signal=True)¶ Use this function together with a with statement to have the signal be unfolded for the scope of the with block, before automatically refolding when passing out of scope.
Examples
>>> import numpy as np >>> s = BaseSignal(np.random.random((64,64,1024))) >>> with s.unfolded(): # Do whatever needs doing while unfolded here pass

update_plot
()¶ If this Signal has been plotted, update the signal and navigator plots, as appropriate.

valuemax
(axis, out=None, rechunk=True)¶ Returns a signal with the value of coordinates of the maximum along an axis.
 Parameters
axis (
int
,str
, orDataAxis
) – The axis can be passed directly, or specified using the index of the axis in the Signal’s axes_manager or the axis name.out (
BaseSignal
(or subclasses) orNone
) – IfNone
, a new Signal is created with the result of the operation and returned (default). If a Signal is passed, it is used to receive the output of the operation, and nothing is returned.rechunk (bool) – Only has effect when operating on lazy signal. If
True
(default), the data may be automatically rechunked before performing this operation.
 Returns
s – A new Signal containing the calibrated coordinate values of the maximum along the specified axis.
 Return type
BaseSignal
(or subclasses)
See also
max()
,min()
,sum()
,mean()
,std()
,var()
,indexmax()
,indexmin()
,valuemin()
Examples
>>> import numpy as np >>> s = BaseSignal(np.random.random((64,64,1024))) >>> s.data.shape (64,64,1024) >>> s.valuemax(1).data.shape (64,64)

valuemin
(axis, out=None, rechunk=True)¶ Returns a signal with the value of coordinates of the minimum along an axis.
 Parameters
axis (
int
,str
, orDataAxis
) – The axis can be passed directly, or specified using the index of the axis in the Signal’s axes_manager or the axis name.out (
BaseSignal
(or subclasses) orNone
) – IfNone
, a new Signal is created with the result of the operation and returned (default). If a Signal is passed, it is used to receive the output of the operation, and nothing is returned.rechunk (bool) – Only has effect when operating on lazy signal. If
True
(default), the data may be automatically rechunked before performing this operation.
 Returns
s – A new Signal containing the calibrated coordinate values of the minimum along the specified axis.
 Return type
BaseSignal
(or subclasses)
See also
max()
,min()
,sum()
,mean()
,std()
,var()
,indexmax()
,indexmin()
,valuemax()

var
(axis=None, out=None, rechunk=True)¶ Returns a signal with the variances of the signal along at least one axis.
 Parameters
axis (
int
,str
,DataAxis
, tuple (of DataAxis) orNone
) – Either one on its own, or many axes in a tuple can be passed. In both cases the axes can be passed directly, or specified using the index in axes_manager or the name of the axis. Any duplicates are removed. IfNone
, the operation is performed over all navigation axes (default).out (
BaseSignal
(or subclasses) orNone
) – IfNone
, a new Signal is created with the result of the operation and returned (default). If a Signal is passed, it is used to receive the output of the operation, and nothing is returned.rechunk (bool) – Only has effect when operating on lazy signal. If
True
(default), the data may be automatically rechunked before performing this operation.
 Returns
s – A new Signal containing the variance of the provided Signal over the specified axes
 Return type
BaseSignal
(or subclasses)
See also
max()
,min()
,sum()
,mean()
,std()
,indexmax()
,indexmin()
,valuemax()
,valuemin()
Examples
>>> import numpy as np >>> s = BaseSignal(np.random.random((64,64,1024))) >>> s.data.shape (64,64,1024) >>> s.var(1).data.shape (64,64)