80 lines
3.3 KiB
Python
80 lines
3.3 KiB
Python
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from typing import Union
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import numpy as np
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from astropy import units as u
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from .IPSF import IPSF
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from scipy.optimize import newton
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from scipy.special import j0, j1
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from ...lib.helpers import error
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class Airy(IPSF):
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"""
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A class for modelling the PSF using an airy disk.
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"""
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@u.quantity_input(wl="length", d_aperture="length")
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def __init__(self, wl: u.Quantity, d_aperture: u.Quantity):
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self.__wl = wl
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self.__d_aperture = d_aperture
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def calcReducedObservationAngle(self, contained_energy: Union[str, int, float, u.Quantity]) -> u.Quantity:
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"""
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Calculate the reduced observation angle in lambda / d_ap for the given contained energy.
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Parameters
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----------
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contained_energy : Union[str, int, float, u.Quantity]
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The percentage of energy to be contained within a circle with the diameter reduced observation angle.
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Returns
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-------
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reduced_observation_angle: Quantity
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The reduced observation angle in lambda / d_ap
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"""
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# Calculate the reduced observation angle in lambda / D for the given encircled energy
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if type(contained_energy) == str:
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# Encircled energy is of type string
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if contained_energy.lower() == "peak":
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# For the peak value of the PSF, the observation angle becomes zero which leads to one exposed
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# pixel later in the code
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reduced_observation_angle = 0
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elif contained_energy.lower() == "fwhm":
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# Width of the FWHM of the airy disk
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reduced_observation_angle = 1.028
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elif contained_energy.lower() == "min":
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# Width of the first minimum of the airy disk
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reduced_observation_angle = 1.22 * 2
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else:
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# Try to parse the encircled energy to float
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reduced_observation_angle = 0
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try:
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contained_energy = float(contained_energy) / 100.0 * u.dimensionless_unscaled
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# Calculate the width numerically from the integral of the airy disk
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# See also https://en.wikipedia.org/wiki/Airy_disk#Mathematical_formulation
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reduced_observation_angle = 2 * newton(lambda x: 1 - j0(np.pi * x) ** 2 - j1(np.pi * x) ** 2 -
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contained_energy, 1, tol=1e-6)
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except ValueError:
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error("Could not convert encircled energy to float.")
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else:
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# Calculate the width numerically from the integral of the airy disk
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reduced_observation_angle = 2 * newton(lambda x: 1 - j0(np.pi * x) ** 2 - j1(np.pi * x) ** 2 -
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contained_energy.value, 1, tol=1e-6)
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return reduced_observation_angle * u.dimensionless_unscaled
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def mapToGrid(self, grid: np.ndarray) -> np.ndarray:
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"""
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Map the integrated PSF values to a sensor grid.
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Parameters
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----------
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grid : ndarray
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The grid to map the values to. The values will only be mapped onto entries with the value 1.
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Returns
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-------
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grid : ndarray
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The grid with the mapped values.
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"""
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pass
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