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# This file is part of ip_isr. 

# 

# Developed for the LSST Data Management System. 

# This product includes software developed by the LSST Project 

# (https://www.lsst.org). 

# See the COPYRIGHT file at the top-level directory of this distribution 

# for details of code ownership. 

# 

# This program is free software: you can redistribute it and/or modify 

# it under the terms of the GNU General Public License as published by 

# the Free Software Foundation, either version 3 of the License, or 

# (at your option) any later version. 

# 

# This program is distributed in the hope that it will be useful, 

# but WITHOUT ANY WARRANTY; without even the implied warranty of 

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 

# GNU General Public License for more details. 

# 

# You should have received a copy of the GNU General Public License 

# along with this program. If not, see <https://www.gnu.org/licenses/>. 

from abc import ABC, abstractmethod 

from typing import Optional 

 

from lsst.pex.config import Config, Field, ListField 

from lsst.pipe.base import Task 

from lsst.geom import Angle 

 

 

class StrayLightConfig(Config): 

doRotatorAngleCorrection = Field( 

dtype=bool, 

doc="", 

default=False, 

) 

filters = ListField( 

dtype=str, 

doc="Filters that need straylight correction.", 

default=[], 

) 

 

 

class StrayLightTask(Task): 

"""Remove stray light from instruments. 

 

This is a dummy task to be retargeted with an camera-specific version. 

""" 

ConfigClass = StrayLightConfig 

_DefaultName = "isrStrayLight" 

 

def readIsrData(self, dataRef, rawExposure): 

"""Read and return calibration products relevant for correcting 

stray light in the given exposure. 

 

Parameters 

---------- 

dataRef : `daf.persistence.butlerSubset.ButlerDataRef` 

Butler reference of the detector data to be processed 

rawExposure : `afw.image.Exposure` 

The raw exposure that will later be corrected with the 

retrieved calibration data; should not be modified in this 

method. 

 

Returns 

------- 

straylightData : `object`, optional 

An opaque object that should be passed as the second argument to 

the `run` method. If `None`, no stray light correction will be 

performed for the given image. Any other object (e.g. `True`) 

may be used to signal that stray light correction should be 

performed even if there is nothing to read. 

 

Notes 

----- 

This method will be called only when `IsrTask` is run by the Gen2 

Middleware (i.e. CmdLineTask). 

""" 

return None 

 

def check(self, exposure): 

"""Check if stray light correction should be run. 

 

Parameters 

---------- 

exposure : `lsst.afw.image.Exposure` 

Exposure to correct. 

""" 

return False 

 

def run(self, exposure, strayLightData): 

"""Correct stray light. 

 

Parameters 

---------- 

exposure : `lsst.afw.image.Exposure` 

Exposure to correct. 

strayLightData : `object`, optional 

An opaque object that contains any calibration data used to 

correct for stray light. 

""" 

raise NotImplementedError("Must be implemented by subclasses.") 

 

def checkFilter(self, exposure): 

"""Check whether we should fringe-subtract the science exposure. 

 

Parameters 

---------- 

exposure : `lsst.afw.image.Exposure` 

Exposure to check the filter of. 

 

Returns 

------- 

needsFringe : `bool` 

If True, then the exposure has a filter listed in the 

configuration, and should have the fringe applied. 

""" 

return exposure.getFilter().getName() in self.config.filters 

 

 

class StrayLightData(ABC): 

"""An abstract base class for rotator-dependent stray light information. 

""" 

 

@abstractmethod 

def evaluate(self, angle_start: Angle, angle_end: Optional[Angle] = None): 

"""Get a stray light array for a range of rotator angles. 

 

Parameters 

---------- 

angle_begin : `float` 

Instrument rotation angle at the start of the exposure. 

angle_end : `float`, optional 

Instrument rotation angle at the end of the exposure. 

If not provided, the returned array will reflect a snapshot at 

`angle_start`. 

 

Returns 

------- 

array : `numpy.ndarray` 

A stray-light background image for this exposure. 

""" 

raise NotImplementedError("Must be implemented by subclasses.")