Source code for rayoptics.raytr.vigcalc

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# Copyright © 2022 Michael J. Hayford
""" Vignetting and clear aperture setting operations

.. Created on Mon Apr 18 15:28:25 2022

.. codeauthor: Michael J. Hayford
"""
import logging

import numpy as np
from numpy import sqrt
from scipy.optimize import newton

import rayoptics.optical.model_constants as mc

from rayoptics.raytr import trace, RayPkg, RaySeg
from rayoptics.raytr import traceerror as terr
from rayoptics.parax import etendue

# label for coordinate chooser
xy_str = 'xy'


[docs] def set_ape(opm): """ From existing fields and vignetting, calculate clear apertures. This function modifies the max_aperture maintained by the list of :class:`~.interface.Interface` in the :class:`~.sequential.SequentialModel`. For each interface, the smallest aperture that will pass all of the (vignetted) boundary rays, for each field, is chosen. The change of the apertures is propagated to the :class:`~.elements.ElementModel` via :meth:`~.elements.ElementModel.sync_to_seq`. """ rayset = trace.trace_boundary_rays(opm, use_named_tuples=True) for i, ifc in enumerate(opm['sm'].ifcs): max_ap = -1.0e+10 update = True for f in rayset: for p in f: ray = p.ray if len(ray) > i: ap = sqrt(ray[i].p[0]**2 + ray[i].p[1]**2) if ap > max_ap: max_ap = ap else: # ray failed before this interface, don't update update = False if update: ifc.set_max_aperture(max_ap) # sync the element model with the new clear apertures opm['em'].sync_to_seq(opm['sm'])
[docs] def set_vig(opm): """ From existing fields and clear apertures, calculate vignetting. """ osp = opm['osp'] for fi in range(len(osp['fov'].fields)): fld, wvl, foc = osp.lookup_fld_wvl_focus(fi) # print(f"field {fi}:") calc_vignetting_for_field(opm, fld, wvl)
[docs] def set_pupil(opm): """ From existing stop size, calculate pupil spec and vignetting. Use the upper Y marginal ray on-axis (field #0) and iterate until it goes through the edge of the stop surface. Use the object or image segments of this ray to update the pupil specification value e.g. EPD, NA or f/#. """ sm = opm['sm'] if sm.stop_surface is None: # Nope, the whole purpose here is to go from aperture stop to pupil print('floating stop surface') return osp = opm['osp'] # iterate the on-axis marginal ray thru the edge of the stop. fld, wvl, foc = osp.lookup_fld_wvl_focus(0) stop_radius = sm.ifcs[sm.stop_surface].surface_od() start_coords = iterate_pupil_ray(opm, sm.stop_surface, 1, 1.0, stop_radius, fld, wvl) print(start_coords) # trace the real axial marginal ray ray_result = trace.trace_safe(opm, start_coords, fld, wvl, None, None, apply_vignetting=False, check_apertures=True) ray_pkg, ray_err = trace.retrieve_ray(ray_result) obj_img_key = osp['pupil'].key[1] pupil_spec = osp['pupil'].key[2] pupil_value_orig = osp['pupil'].value if obj_img_key == 'object': if pupil_spec == 'epd' or pupil_spec == 'pupil': rs1 = RaySeg(*ray_pkg[0][1]) ht = rs1.p[1] osp['pupil'].value = 2*ht else: rs0 = RaySeg(*ray_pkg[0][0]) slp0 = rs0.d[1]/rs0.d[2] if pupil_spec == 'NA': n0 = sm.rindx[0] osp['pupil'].value = n0*rs0.d[1] # osp['pupil'].value = etendue.slp2na(slp0) elif pupil_spec == 'f/#': osp['pupil'].value = 1/(2*slp0) elif obj_img_key == 'image': rsm2 = RaySeg(*ray_pkg[0][-2]) if pupil_spec == 'epd' or pupil_spec == 'pupil': ht = rsm2.p[1] osp['pupil'].value = 2*ht else: slpk = rsm2.d[1]/rsm2.d[2] if pupil_spec == 'NA': nk = sm.rindx[-1] osp['pupil'].value = -nk*rsm2.d[1] # osp['pupil'].value = etendue.slp2na(slpk) elif pupil_spec == 'f/#': osp['pupil'].value = -1/(2*slpk) if pupil_value_orig != osp['pupil'].value: opm.update_model() set_vig(opm)
[docs] def calc_vignetting_for_field(opm, fld, wvl): """Calculate and set the vignetting parameters for `fld`. """ pupil_starts = opm['osp']['pupil'].pupil_rays[1:] vig_factors = [0.]*4 for i in range(4): xy = i//2 start = pupil_starts[i] vig, last_indx, ray_pkg = calc_vignetted_ray(opm, xy, start, fld, wvl) # print(f"ray: ({start[0]:2.0f}, {start[1]:2.0f}), vig={vig:8.4f}, " # f"limited at ifcs[{last_indx}]") vig_factors[i] = vig # update the field's vignetting factors fld.vux = vig_factors[0] fld.vlx = vig_factors[1] fld.vuy = vig_factors[2] fld.vly = vig_factors[3]
[docs] def calc_vignetted_ray(opm, xy, start_dir, fld, wvl, max_iter_count=10): """ Find the limiting aperture and return the vignetting factor. Args: opm: :class:`~.OpticalModel` instance xy: 0 or 1 depending on x or y axis as the pupil direction start_dir: the unit length starting pupil coordinates, e.g [1., 0.]. This establishes the radial direction of the ray iteration. fld: :class:`~.Field` point for wave aberration calculation wvl: wavelength of ray (nm) max_iter_count: fail-safe limit on aperture search Returns: (**vig**, **last_indx**, **ray_pkg**) - **vig** - vignetting factor - **last_indx** - the index of the limiting interface - **ray_pkg** - the vignetting-limited ray """ rel_p1 = np.array(start_dir) sm = opm['sm'] still_iterating = True last_indx = None iter_count = 0 # safe guard against runaway iteration while still_iterating and iter_count<max_iter_count: iter_count += 1 try: ray_pkg = trace.trace_base(opm, rel_p1, fld, wvl, apply_vignetting=False, check_apertures=True) except terr.TraceError as ray_error: indx = ray_error.surf ray_pkg = ray_error.ray_pkg # print(f"{xy_str[xy]} = {rel_p1[xy]:10.6f}: blocked at {indx}") if indx == last_indx: still_iterating = False else: r_target = sm.ifcs[indx].edge_pt_target(start_dir) rel_p1 = iterate_pupil_ray(opm, indx, xy, rel_p1[xy], r_target[xy], fld, wvl) still_iterating = True last_indx = indx else: # ray successfully traced. # print(f"{xy_str[xy]} = {rel_p1[xy]:10.6f}: passed") if last_indx is not None: # fall through and exit still_iterating = False else: # this is the first time through # iterate to find the ray that goes through the edge # of the stop surface indx = stop_indx = sm.stop_surface if stop_indx is not None: r_target = sm.ifcs[stop_indx].edge_pt_target(start_dir) rel_p1 = iterate_pupil_ray(opm, indx, xy, rel_p1[xy], r_target[xy], fld, wvl) still_iterating = True last_indx = indx else: # floating stop, exit still_iterating = False vig = 1.0 - (rel_p1[xy]/start_dir[xy]) return vig, last_indx, ray_pkg
[docs] def iterate_pupil_ray(opt_model, indx, xy, start_r0, r_target, fld, wvl, **kwargs): """ iterates a ray to r_target on interface indx, returns aim points on the paraxial entrance pupil plane If indx is None, i.e. a floating stop surface, returns r_target. If the iteration fails, a :class:`~.traceerror.TraceError` will be raised Args: opm: :class:`~.OpticalModel` instance indx: index of interface whose edge is the iteration target xy: 0 or 1 depending on x or y axis as the pupil direction start_r0: iteration starting point r_target: clear aperture radius that is the iteration target. fld: :class:`~.Field` point for wave aberration calculation wvl: wavelength of ray (nm) Returns: start_coords: pupil coordinates for ray thru r_target on ifc indx. """ def r_pupil_coordinate(xy_coord, *args): opt_model, indx, xy, fld, wvl, r_target = args rel_p1 = np.array([0., 0.]) rel_p1[xy] = xy_coord try: ray_pkg = trace.trace_base(opt_model, rel_p1, fld, wvl, apply_vignetting=False, check_apertures=False) except terr.TraceError as ray_error: ray_pkg = ray_error.ray_pkg if ray_error.surf < indx: raise ray_error ray = ray_pkg[mc.ray] r_ray = ray[indx][mc.p][xy] # print(xy_coord, r_ray, r_target, r_ray - r_target) return r_ray - r_target start_coords = np.array([0., 0.]) if indx is not None: logging.captureWarnings(True) try: start_r, results = newton(r_pupil_coordinate, start_r0, args=(opt_model, indx, xy, fld, wvl, r_target), tol=1e-6, disp=False, full_output=True) except RuntimeError as rte: # if we come here, set start_r to a RuntimeResults object start_r = results.root except terr.TraceError: start_r = 0.0 start_coords[xy] = start_r # print(f"converged={results.converged} in {results.iterations} iterations") else: # floating stop surface - use entrance pupil for aiming start_coords[xy] = r_target return start_coords