LSST Applications 27.0.0,g0265f82a02+469cd937ee,g02d81e74bb+21ad69e7e1,g1470d8bcf6+cbe83ee85a,g2079a07aa2+e67c6346a6,g212a7c68fe+04a9158687,g2305ad1205+94392ce272,g295015adf3+81dd352a9d,g2bbee38e9b+469cd937ee,g337abbeb29+469cd937ee,g3939d97d7f+72a9f7b576,g487adcacf7+71499e7cba,g50ff169b8f+5929b3527e,g52b1c1532d+a6fc98d2e7,g591dd9f2cf+df404f777f,g5a732f18d5+be83d3ecdb,g64a986408d+21ad69e7e1,g858d7b2824+21ad69e7e1,g8a8a8dda67+a6fc98d2e7,g99cad8db69+f62e5b0af5,g9ddcbc5298+d4bad12328,ga1e77700b3+9c366c4306,ga8c6da7877+71e4819109,gb0e22166c9+25ba2f69a1,gb6a65358fc+469cd937ee,gbb8dafda3b+69d3c0e320,gc07e1c2157+a98bf949bb,gc120e1dc64+615ec43309,gc28159a63d+469cd937ee,gcf0d15dbbd+72a9f7b576,gdaeeff99f8+a38ce5ea23,ge6526c86ff+3a7c1ac5f1,ge79ae78c31+469cd937ee,gee10cc3b42+a6fc98d2e7,gf1cff7945b+21ad69e7e1,gfbcc870c63+9a11dc8c8f
LSST Data Management Base Package
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wcsUtils.py
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1# This file is part of afw.
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
22__all__ = ["getSipMatrixFromMetadata", "computePixelToDistortedPixel",
23 "createTrivialWcsMetadata", "deleteBasicWcsMetadata", "getCdMatrixFromMetadata",
24 "getImageXY0FromMetadata", "hasSipMatrix", "makeSipMatrixMetadata",
25 "makeTanSipMetadata"]
26
27import lsst.geom
28from ._geom import (_getSipMatrixFromMetadata, makeTransform, linearizeTransform,
29 createTrivialWcsMetadata, deleteBasicWcsMetadata, getCdMatrixFromMetadata,
30 getImageXY0FromMetadata, hasSipMatrix, makeSipMatrixMetadata,
31 makeTanSipMetadata)
32
33
34def getSipMatrixFromMetadata(metadata, name):
35 """Extract a SIP matrix from FITS TAN-SIP WCS metadata.
36
37 Omitted coefficients are set to 0 and all coefficients may be omitted.
38
39 Parameters
40 ----------
41 metadata : `lsst.daf.base.PropertySet`
42 FITS metadata.
43 name : `str`
44 Name of TAN-SIP matrix (``"A"``, ``"B"``, ``"Ap"``, or ``"Bp"``).
45
46 Returns
47 -------
48 `numpy.array`
49 The SIP matrix.
50
51 Raises
52 ------
53 TypeError
54 If the order keyword ``<name>_ORDER`` (e.g. ``AP_ORDER``) is not found,
55 the value of the order keyword cannot be read as an integer,
56 the value of the order keyword is negative,
57 or if a matrix parameter (e.g. ``AP_5_0``) cannot be read as a float.
58 """
59 arr = _getSipMatrixFromMetadata(metadata, name)
60 if arr.shape == (): # order=0
61 arr.shape = (1, 1)
62 return arr
63
64
65def computePixelToDistortedPixel(pixelToFocalPlane, focalPlaneToFieldAngle):
66 """Compute the transform ``pixelToDistortedPixel``, which applies optical
67 distortion specified by ``focalPlaneToFieldAngle``.
68
69 The resulting transform is designed to be used to convert a pure TAN WCS
70 to a WCS that includes a model for optical distortion. In detail,
71 the initial WCS will contain these frames and transforms::
72
73 PIXELS frame -> pixelToIwc -> IWC frame -> gridToIwc -> SkyFrame
74
75 To produce the WCS with distortion, replace ``pixelToIwc`` with::
76
77 pixelToDistortedPixel -> pixelToIwc
78
79 Parameters
80 ----------
81 pixelToFocalPlane : `lsst.afw.geom.TransformPoint2ToPoint2`
82 Transform parent pixel coordinates to focal plane coordinates
83 focalPlaneToFieldAngle : `lsst.afw.geom.TransformPoint2ToPoint2`
84 Transform focal plane coordinates to field angle coordinates
85
86 Returns
87 -------
88 pixelToDistortedPixel : `lsst.afw.geom.TransformPoint2ToPoint2`
89 A transform that applies the effect of the optical distortion model.
90 """
91 # return pixelToFocalPlane -> focalPlaneToFieldAngle -> tanFieldAngleToocalPlane -> focalPlaneToPixel
92 focalPlaneToTanFieldAngle = makeTransform(linearizeTransform(focalPlaneToFieldAngle,
93 lsst.geom.Point2D(0, 0)))
94 return pixelToFocalPlane.then(focalPlaneToFieldAngle) \
95 .then(focalPlaneToTanFieldAngle.inverted()) \
96 .then(pixelToFocalPlane.inverted())
computePixelToDistortedPixel(pixelToFocalPlane, focalPlaneToFieldAngle)
Definition wcsUtils.py:65
getSipMatrixFromMetadata(metadata, name)
Definition wcsUtils.py:34