optiland.wavefront.zernike_opd

This module defines the ZernikeOPD class.

Kramer Harrison, 2024

Classes

ZernikeOPD(optic, field, wavelength[, ...])

Represents a Zernike Optical Path Difference (OPD) calculation.
class ZernikeOPD(optic: Optic, field: tuple[float, float], wavelength: str | float, num_rings: int = 15, zernike_type: ZernikeType = 'fringe', num_terms: int = 37, strategy: WavefrontStrategyType = 'chief_ray', remove_tilt: bool = False, **kwargs)[source]

Represents a Zernike Optical Path Difference (OPD) calculation.

This class inherits from both the ZernikeFit and OPD classes. It first generates the OPD map(s), then fits Zernike polynomials to the map(s).

Parameters:

  • optic (object) – The optic object representing the optical system.

  • field (tuple) – The field used for the calculation.

  • wavelength (str | float) – The wavelength of light used in the calculation. Can be ‘primary’ or a float value.

  • num_rings (int, optional) – The number of rings used in the Zernike calculation. Default is 15.

  • zernike_type (str, optional) – The type of Zernike polynomials used. Default is ‘fringe’. See zernike module for more information.

  • num_terms (int, optional) – The number of Zernike terms used in the calculation. Default is 37.

  • strategy (str) – The calculation strategy to use. Supported options are “chief_ray”, “centroid_sphere”, and “best_fit_sphere”. Defaults to “chief_ray”.

  • remove_tilt (bool) – If True, removes tilt and piston from the OPD data. Defaults to False.

  • **kwargs – Additional keyword arguments passed to the strategy, including the afocal boolean flag to indicate if the system is afocal.

property coeffs: BEArray

The fitted Zernike coefficients.

Type:

Tensor

static fit_and_remove_tilt(data: WavefrontData, remove_piston: bool = False, ridge: float = 1e-12) → be.ndarray

Removes piston and tilt from OPD data using weighted least squares.

Parameters:

  • data (WavefrontData) – The wavefront data containing pupil coordinates and OPD.

  • remove_piston (bool, optional) – If True, removes piston term as well as tilt. Defaults to False.

  • ridge (float, optional) – Small diagonal regularization for stability. Defaults to 1e-12.

Returns:

OPD with piston and tilt removed, shape (N,).

Return type:

opd_detrended (be.ndarray)

generate_opd_map(num_points: int = 256) → OPDData

Generates the OPD map data.

Parameters:

num_points (int, optional) – The number of points for interpolation along each axis of the grid. Defaults to 256.

Returns:

A dictionary containing the interpolated OPD map, with keys ‘x’, ‘y’, and ‘z’. The values are NumPy arrays.

Return type:

dict[str, np.ndarray]

get_data(field: tuple[float, float], wl: float) → WavefrontData

Retrieves precomputed wavefront data for a field and wavelength.

Parameters:

  • field (tuple[float, float]) – The field coordinates, or a FieldPoint.

  • wl (float) – The wavelength in µm, or a WavelengthPoint.

Returns:

A data container with the computed wavefront results.

Return type:

WavefrontData

rms() → be.ndarray

Calculates the root mean square (RMS) of the OPD wavefront.

Returns:

The RMS value.

Return type:

float

view(fig_to_plot_on: Figure | None = None, projection: str = '2d', num_points: int = 128, figsize: tuple[float, float] = (7, 5.5), z_label: str = 'OPD (waves)') → tuple[Figure, Axes]

Visualize the fitted Zernike surface.

Parameters:

  • fig_to_plot_on (plt.Figure, optional) – Figure to plot on. If None, a new figure is created.

  • projection (str) – ‘2d’ for image plot, ‘3d’ for surface plot.

  • num_points (int) – Grid resolution for display.

  • figsize (tuple) – Figure size in inches.

  • to (defaults)

  • z_label (str) – Label for the z-axis or colorbar.

  • 'OPD (defaults to)

Returns:

A tuple containing the figure and axes objects.

Return type:

tuple

Raises:

ValueError – If projection is not ‘2d’ or ‘3d’.

view_residual(fig_to_plot_on: Figure | None = None, figsize: tuple[float, float] = (7, 5.5), z_label: str = 'Residual (waves)')

Scatter plot of residuals between fitted surface and original data.

Parameters:

  • fig_to_plot_on (plt.Figure, optional) – Figure to plot on. If None, a new figure is created.

  • figsize (tuple) – Figure size in inches. Defaults to (7, 5.5).

  • z_label (str) – Label for the colorbar. Defaults to ‘Residual (waves)’.

Returns:

A tuple containing the figure and axes objects.

Return type:

tuple