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LSST Data Management Base Package
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photodiode.py
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1# This file is part of ip_isr.
2#
3# Developed for the LSST Data Management System.
4# This product includes software developed by the LSST Project
5# (https://www.lsst.org).
6# See the COPYRIGHT file at the top-level directory of this distribution
7# for details of code ownership.
8#
9# This program is free software: you can redistribute it and/or modify
10# it under the terms of the GNU General Public License as published by
11# the Free Software Foundation, either version 3 of the License, or
12# (at your option) any later version.
13#
14# This program is distributed in the hope that it will be useful,
15# but WITHOUT ANY WARRANTY; without even the implied warranty of
16# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17# GNU General Public License for more details.
18#
19# You should have received a copy of the GNU General Public License
20# along with this program. If not, see <https://www.gnu.org/licenses/>.
21"""
22Photodiode storage class.
23"""
24
25__all__ = ["PhotodiodeCalib"]
26
27import numpy as np
28from astropy.table import Table
29
30from lsst.ip.isr import IsrCalib
31
32
34 """Independent current measurements from photodiode for linearity
35 calculations.
36
37 Parameters
38 ----------
39 timeSamples : `list` or `numpy.ndarray`
40 List of samples the photodiode was measured at.
41 currentSamples : `list` or `numpy.ndarray`
42 List of current measurements at each time sample.
43 log : `lsst.log.Log`, optional
44 Log to write messages to.
45 **kwargs :
46 Additional parameters. These will be passed to the parent
47 constructor with the exception of:
48
49 ``"integrationMethod"``
50 Name of the algorithm to use to integrate the current
51 samples. Allowed values are ``DIRECT_SUM``,
52 ``TRIMMED_SUM``, and ``CHARGE_SUM`` (`str`).
53 ``"currentScale"``
54 Scale factor to apply to the current samples for the
55 ``CHARGE_SUM`` integration method. A typical value
56 would be `-1`, to flip the sign of the integrated charge.
57 """
58
59 _OBSTYPE = 'PHOTODIODE'
60 _SCHEMA = 'Photodiode'
61 _VERSION = 1.0
62
63 def __init__(self, timeSamples=None, currentSamples=None, **kwargs):
64 if timeSamples is not None and currentSamples is not None:
65 if len(timeSamples) != len(currentSamples):
66 raise RuntimeError(f"Inconsitent vector lengths: {len(timeSamples)} vs {len(currentSamples)}")
67 else:
68 self.timeSamples = np.array(timeSamples).ravel()
69 self.currentSamples = np.array(currentSamples).ravel()
70 else:
71 self.timeSamples = np.array([]).ravel()
72 self.currentSamples = np.array([]).ravel()
73
74 super().__init__(**kwargs)
75
76 if 'integrationMethod' in kwargs:
77 self.integrationMethod = kwargs.pop('integrationMethod')
78 else:
79 self.integrationMethod = 'DIRECT_SUM'
80
81 if 'currentScale' in kwargs:
82 self.currentScale = kwargs.pop('currentScale')
83 else:
84 self.currentScale = 1.0
85
86 if 'day_obs' in kwargs:
87 self.updateMetadata(day_obs=kwargs['day_obs'])
88 if 'seq_num' in kwargs:
89 self.updateMetadata(seq_num=kwargs['seq_num'])
90
91 self.requiredAttributesrequiredAttributesrequiredAttributes.update(['timeSamples', 'currentSamples', 'integrationMethod'])
92
93 @classmethod
94 def fromDict(cls, dictionary):
95 """Construct a PhotodiodeCalib from a dictionary of properties.
96
97 Parameters
98 ----------
99 dictionary : `dict`
100 Dictionary of properties.
101
102 Returns
103 -------
104 calib : `lsst.ip.isr.PhotodiodeCalib`
105 Constructed photodiode data.
106
107 Raises
108 ------
109 RuntimeError
110 Raised if the supplied dictionary is for a different
111 calibration type.
112 """
113 calib = cls()
114
115 if calib._OBSTYPE != dictionary['metadata']['OBSTYPE']:
116 raise RuntimeError(f"Incorrect photodiode supplied. Expected {calib._OBSTYPE}, "
117 f"found {dictionary['metadata']['OBSTYPE']}")
118
119 calib.setMetadata(dictionary['metadata'])
120
121 calib.timeSamples = np.array(dictionary['timeSamples']).ravel()
122 calib.currentSamples = np.array(dictionary['currentSamples']).ravel()
123 calib.integrationMethod = dictionary.get('integrationMethod', "DIRECT_SUM")
124
125 calib.updateMetadata()
126 return calib
127
128 def toDict(self):
129 """Return a dictionary containing the photodiode properties.
130
131 The dictionary should be able to be round-tripped through.
132 `fromDict`.
133
134 Returns
135 -------
136 dictionary : `dict`
137 Dictionary of properties.
138 """
139 self.updateMetadata()
140
141 outDict = {}
142 outDict['metadata'] = self.getMetadata()
143
144 outDict['timeSamples'] = self.timeSamples.tolist()
145 outDict['currentSamples'] = self.currentSamples.tolist()
146
147 outDict['integrationMethod'] = self.integrationMethod
148
149 return outDict
150
151 @classmethod
152 def fromTable(cls, tableList):
153 """Construct calibration from a list of tables.
154
155 This method uses the `fromDict` method to create the
156 calibration after constructing an appropriate dictionary from
157 the input tables.
158
159 Parameters
160 ----------
161 tableList : `list` [`astropy.table.Table`]
162 List of tables to use to construct the crosstalk
163 calibration.
164
165 Returns
166 -------
167 calib : `lsst.ip.isr.PhotodiodeCalib`
168 The calibration defined in the tables.
169 """
170 dataTable = tableList[0]
171
172 metadata = dataTable.meta
173 inDict = {}
174 inDict['metadata'] = metadata
175 inDict['integrationMethod'] = metadata.pop('INTEGRATION_METHOD', 'DIRECT_SUM')
176
177 inDict['timeSamples'] = dataTable['TIME']
178 inDict['currentSamples'] = dataTable['CURRENT']
179
180 return cls().fromDict(inDict)
181
182 def toTable(self):
183 """Construct a list of tables containing the information in this
184 calibration.
185
186 The list of tables should create an identical calibration
187 after being passed to this class's fromTable method.
188
189 Returns
190 -------
191 tableList : `list` [`astropy.table.Table`]
192 List of tables containing the photodiode calibration
193 information.
194 """
195 self.updateMetadata()
196 catalog = Table([{'TIME': self.timeSamples,
197 'CURRENT': self.currentSamples}])
198 inMeta = self.getMetadata().toDict()
199 outMeta = {k: v for k, v in inMeta.items() if v is not None}
200 outMeta.update({k: "" for k, v in inMeta.items() if v is None})
201 outMeta['INTEGRATION_METHOD'] = self.integrationMethod
202 catalog.meta = outMeta
203
204 return [catalog]
205
206 @classmethod
207 def readTwoColumnPhotodiodeData(cls, filename):
208 """Construct a PhotodiodeCalib by reading the simple column format.
209
210 Parameters
211 ----------
212 filename : `str`
213 File to read samples from.
214
215 Returns
216 -------
217 calib : `lsst.ip.isr.PhotodiodeCalib`
218 The calibration defined in the file.
219 """
220 import os.path
221
222 rawData = np.loadtxt(filename, dtype=[('time', 'float'), ('current', 'float')])
223
224 basename = os.path.basename(filename)
225 cleaned = os.path.splitext(basename)[0]
226 _, _, day_obs, seq_num = cleaned.split("_")
227
228 return cls(timeSamples=rawData['time'], currentSamples=rawData['current'],
229 day_obs=int(day_obs), seq_num=int(seq_num))
230
231 def integrate(self):
232 """Integrate the current.
233
234 Raises
235 ------
236 RuntimeError
237 Raised if the integration method is not known.
238 """
239 if self.integrationMethod == 'DIRECT_SUM':
240 return self.integrateDirectSum()
241 elif self.integrationMethod == 'TRIMMED_SUM':
242 return self.integrateTrimmedSum()
243 elif self.integrationMethod == 'CHARGE_SUM':
244 return self.integrateChargeSum()
245 else:
246 raise RuntimeError(f"Unknown integration method {self.integrationMethod}")
247
249 """Integrate points.
250
251 This uses numpy's trapezoidal integrator.
252
253 Returns
254 -------
255 sum : `float`
256 Total charge measured.
257 """
258 return np.trapz(self.currentSamples, x=self.timeSamples)
259
261 """Integrate points with a baseline level subtracted.
262
263 This uses numpy's trapezoidal integrator.
264
265 Returns
266 -------
267 sum : `float`
268 Total charge measured.
269
270 See Also
271 --------
272 lsst.eotask.gen3.eoPtc
273 """
274 currentThreshold = ((max(self.currentSamples) - min(self.currentSamples))/5.0
275 + min(self.currentSamples))
276 lowValueIndices = np.where(self.currentSamples < currentThreshold)
277 baseline = np.median(self.currentSamples[lowValueIndices])
278 return np.trapz(self.currentSamples - baseline, self.timeSamples)
279
281 """For this method, the values in .currentSamples are actually the
282 integrated charge values as measured by the ammeter for each
283 sampling interval. We need to do a baseline subtraction,
284 based on the charge values when the LED is off, then sum up
285 the corrected signals.
286
287 Returns
288 -------
289 sum : `float`
290 Total charge measured.
291 """
292 dt = self.timeSamples[1:] - self.timeSamples[:-1]
293 # The .currentSamples values are the current integrals over
294 # the interval preceding the current time stamp, so omit the
295 # first value.
296 charge = self.currentScale*self.currentSamples[1:]
297 # The current per interval to use for baseline subtraction
298 # without assuming all of the dt values are the same:
299 current = charge/dt
300 # To determine the baseline current level, exclude points with
301 # signal levels > 5% of the maximum (measured relative to the
302 # overall minimum), and extend that selection 2 entries on
303 # either side to avoid otherwise low-valued points that sample
304 # the signal ramp and which should not be included in the
305 # baseline estimate.
306 dy = np.max(current) - np.min(current)
307 signal, = np.where(current > dy/20. + np.min(current))
308 imin = signal[0] - 2
309 imax = signal[-1] + 2
310 bg = np.concatenate([np.arange(0, imin), np.arange(imax, len(current))])
311 bg_current = np.sum(charge[bg])/np.sum(dt[bg])
312 # Return the background-subtracted total charge.
313 return np.sum(charge - bg_current*dt)
int min
int max
updateMetadata(self, camera=None, detector=None, filterName=None, setCalibId=False, setCalibInfo=False, setDate=False, **kwargs)
Definition calibType.py:197
__init__(self, timeSamples=None, currentSamples=None, **kwargs)
Definition photodiode.py:63