prysm.mtf_utils¶

Utilities for working with MTF data.

class prysm.mtf_utils.MTFvFvF(data, focus, field, freq, azimuth)¶

Bases: object

Abstract object representing a cube of MTF vs Field vs Focus data.

azimuth¶

Azimuth associated with the data

Type: str

data¶

3D array of data in shape (focus, field, freq)

Type: numpy.ndarray

field¶

array of fields associated with the field axis of data

Type: numpy.ndarray

focus¶

array of focus associated with the focus axis of data

Type: numpy.ndarray

freq¶

array of frequencies associated with the frequency axis of data

Type: numpy.ndarray

plot2d(freq, symmetric=False, contours=True, interp_method='lanczos', fig=None, ax=None)¶

Create a 2D plot of the cube, an “MTF vs Field vs Focus” plot.

Parameters

freq (float) – frequency to plot, will be rounded to the closest value present in the self.freq iterable
symmetric (bool) – make the plot symmetric by mirroring it about the x-axis origin
contours (bool) – plot contours
interp_method (string) – interpolation method used for the plot
fig (matplotlib.figure.Figure, optional:) – Figure to plot inside
ax (matplotlib.axes.Axis, optional:) – Axis to plot inside

Returns

fig (matplotlib.figure.Figure) – figure containing the plot
axis (matplotlib.axes.Axis) – axis containing the plot

plot_thrufocus_singlefield(field, freqs=(10, 20, 30, 40, 50), _range=100, fig=None, ax=None)¶

Create a plot of Thru-Focus MTF for a single field point.

Parameters

field (float) – which field point to plot, in same units as self.field
freqs (iterable) – frequencies to plot, will be rounded to the closest values present in the self.freq iterable
_range (float) – +/- focus range to plot, symmetric
fig (matplotlib.figure.Figure, optional) – Figure to plot inside
ax (matplotlib.axes.Axis) – Axis to plot inside

Returns

fig (matplotlib.figure.Figure, optional) – figure containing the plot
axis (matplotlib.axes.Axis) – axis containing the plot

trace_focus(algorithm='avg')¶

Find the focus position in each field.

This is, in effect, the “field curvature” for this azimuth.

Parameters

algorithm (str) – algorithm to use to trace focus, currently only supports ‘0.5’, see notes for a description of this technique

Returns

field (numpy.ndarray) – array of field values, mm
focus (numpy.ndarray) – array of focus values, microns

Notes

Algorithm ‘0.5’ uses the frequency that has its peak closest to 0.5 on-axis to estimate the focus coresponding to the minimum RMS WFE condition. This is based on the following assumptions:

Any combination of third, fifth, and seventh order spherical
aberration will produce a focus shift that depends on frequency, and this dependence can be well fit by an equation of the form y(x) = ax^2 + bx + c. If this is true, then the frequency which peaks at 0.5 will be near the vertex of the quadratic, which converges to the min RMS WFE condition.
Coma, while it enhances depth of field, does not shift the
focus peak.
Astigmatism and field curvature are the dominant cause of any
shift in best focus with field.
Chromatic aberrations do not influence the thru-focus MTF peak
in a way that varies with field.

Raises: ValueError – if an unsupported algorithm is entered

static from_dataframe(df)¶

Return a pair of MTFvFvF objects for the tangential and one for the sagittal MTF.

Parameters

df (pandas.DataFrame) – a dataframe with columns Focus, Field, Freq, Azimuth, MTF

Returns

t_cube (MTFvFvF) – tangential MTFvFvF
s_cube (MTFvFvF) – sagittal MTFvFvF

static from_trioptics_file(file_path)¶

Create a new MTFvFvF object from a trioptics file.

Parameters: file_path (path_like) – path to a file
Returns: new MTFvFvF object
Return type: MTFvFvF

prysm.mtf_utils.plot_mtf_vs_field(data_dict, fig=None, ax=None, labels=('MTF', 'Freq [lp/mm]', 'Field [mm]', 'Az'), palette=None)¶

Plot MTF vs Field.

Parameters

data_dict (dict) – dictionary with keys tan, sag, fields, freq
fig (matplotlib.figure.Figure, optional) – figure containing the plot
axis (matplotlib.axes.Axis) – axis containing the plot

Returns

fig (matplotlib.figure.Figure, optional) – figure containing the plot
axis (matplotlib.axes.Axis) – axis containing the plot

prysm.mathops

prysm.objects