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
|
#!casa-script
# -*- mode: python -*-
#
# Copyright (c) 2017 Aaron LI <aly@aaronly.me>
# MIT License
#
"""
Add random Gaussian noises to the MeasurementSet DATA.
NOTE: the input MS is modified in place.
"""
import sys
import argparse
import numpy as np
# from casac.ms import ms
def add_noise(msname, sigma):
print("Opening MS: %s ..." % msname)
ms.open(msname, nomodify=False)
ms.selectinit(datadescid=0)
print("Geting MS data column ...")
rec = ms.getdata(["data"])
data = rec["data"]
print("data mean: (%g, %g)" % (data.real.mean(), data.imag.mean()))
print("data std: (%g, %g)" % (data.real.std(), data.imag.std()))
print("Add Gaussian noises sigma=%g ..." % sigma)
nreal = np.random.normal(scale=sigma, size=data.shape)
nimag = np.random.normal(scale=sigma, size=data.shape)
noise = nreal + 1j*nimag
data += noise
rec = {"data": data}
ms.putdata(rec)
ms.writehistory("Add Gaussian noises: sigma=%g" % sigma)
ms.close()
print("Closed MS: %s" % msname)
def main(argv):
parser = argparse.ArgumentParser(
description="Add random noise to MS visibilities")
parser.add_argument("-s", "--sigma", dest="sigma",
required=True, type=float,
help="sigma of the random Gaussian noises")
parser.add_argument("-m", "--ms", dest="ms", required=True,
help="input MeasurementSet to be modified")
args = parser.parse_args(argv)
add_noise(args.ms, sigma=args.sigma)
if __name__ == "__main__":
argi = sys.argv.index("--") + 1
argv = sys.argv[argi:]
print("argv:", argv)
main(argv)
|
