1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
|
#!/usr/bin/env python3
#
# Copyright (c) 2017 Weitian LI <liweitianux@live.com>
# MIT license
#
# 2017-04-08
#
"""
Make images from simulated visibilities using CASA 'clean' task.
Credits
-------
[1] CASA: Common Astronomy Software Applications
https://casa.nrao.edu/
[2] CASA: clean
https://casa.nrao.edu/docs/TaskRef/clean-task.html
[2] GitHub: OxfordSKA/EoR - EoR_pipeline/make_images.py
https://github.com/OxfordSKA/EoR/blob/master/EoR_pipeline/make_images.py
"""
import os
import sys
import argparse
import subprocess
try:
from configparser import ConfigParser
except ImportError:
# CASA (4.7) ships Python 2.7
from ConfigParser import ConfigParser
class Settings:
"""
Manage settings for imaging.
"""
def __init__(self, infile):
self.infile = infile
# Python 2.7's ConfigParser doesn't have parameter 'interpolation'
config = ConfigParser()
config.read(infile)
DEFAULTS = {
"casa_bin": "casa",
"output_ms_fn": "visibility/visibility_{freq:.2f}.ms",
"output_image_rootname": "image/image_{freq:.2f}",
"clean_niter": '500', # int
"clean_gridmode": "widefield",
"clean_wprojplanes": '256', # int
"clean_weighting": "natural",
"clean_uvrange": "",
}
casa_bin = config.get("my", "casa_bin", vars=DEFAULTS)
self.casa_bin = os.path.expanduser(casa_bin)
# Width/X and height/Y of the input FITS image (unit: pixel)
size = config.get("my", "image_size").split(",")
self.image_width = int(size[0])
self.image_height = int(size[1])
self.image_size = (self.image_width, self.image_height)
# Pixel size of the input FITS image (unit: arcsec)
self.image_pixsize = config.getfloat("my", "image_pixsize")
# String format pattern for the output simulated visibility
# data in MeasurementSet format.
self.output_ms_fn = config.get("my", "output_ms_fn", vars=DEFAULTS)
# String format pattern for the output image rootname created
# from visibility using CASA 'clean' task.
self.output_image_rootname = config.get(
"my", "output_image_rootname", vars=DEFAULTS)
# Number of iteration over which to clean (i.e., deconvolve the
# dirty image)
# NOTE: Python 2.7's .getint() not support 'vars' parameter
self.clean_niter = int(config.get("my", "clean_niter", vars=DEFAULTS))
# Apply corrections for non-coplanar effects during imaging
# using the W-Projection algorithm
self.clean_gridmode = config.get("my", "clean_gridmode",
vars=DEFAULTS)
# Number of pre-computed w-planes used for the W-Projection
# algorithm
self.clean_wprojplanes = int(config.get("my", "clean_wprojplanes",
vars=DEFAULTS))
# Decides how much weight is given to uv grid points to allow
# for different sampling densities
self.clean_weighting = config.get("my", "clean_weighting",
vars=DEFAULTS)
# Range of baselines to include when generating the image
self.clean_uvrange = config.get("my", "clean_uvrange", vars=DEFAULTS)
class Imager:
"""
Imager using CASA 'clean' task to create image from visibility.
"""
def __init__(self, ms, rootname):
self.ms = ms
self.rootname = rootname
def make_image(self, settings):
"""
Make image from visibility using 'clean' task.
"""
default(clean)
ret = clean(
vis=self.ms,
imagename=self.rootname,
niter=settings.clean_niter,
gridmode=settings.clean_gridmode,
wprojplanes=settings.clean_wprojplanes,
uvrange=settings.clean_uvrange,
weighting=settings.clean_weighting,
imsize=[settings.image_width, settings.image_height],
cell=[settings.image_pixsize, settings.image_pixsize]
)
return ret
def export_fits(self):
"""
Export create image & psf into FITS.
"""
for imgtype in ["image", "psf"]:
imgfile = "%s.%s" % (self.rootname, imgtype)
fitsfile = imgfile + ".fits"
exportfits(imagename=imgfile, fitsimage=fitsfile)
def main_casa():
imgroot = sys.argv[-1]
msfile = sys.argv[-2]
configfile = sys.argv[-3]
settings = Settings(configfile)
imager = Imager(msfile, imgroot)
imager.make_image(settings)
imager.export_fits()
def main():
parser = argparse.ArgumentParser(
description="Make images from visibilities using CASA")
parser.add_argument("config", help="Configuration file")
parser.add_argument("frequency", type=float,
help="frequency slice to imaging [MHz]")
args = parser.parse_args()
settings = Settings(args.config)
msfile = settings.output_ms_fn.format(freq=args.frequency)
imgroot = settings.output_image_rootname.format(freq=args.frequency)
dname = os.path.dirname(imgroot)
if not os.path.isdir(dname):
os.makedirs(dname)
cmd = [
settings.casa_bin, "--nogui", "--nologger", "--log2term",
"-c", __file__, args.config, msfile, imgroot
]
print("CMD: %s" % " ".join(cmd))
subprocess.check_call(cmd)
if __name__ == "__main__":
progname = os.path.basename(sys.argv[0])
if progname in ["casa", "casapy", "casapy.py"]:
main_casa()
else:
main()
|
