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#!/usr/bin/env python3
#
# Copyright (c) 2017 Weitian LI <liweitianux@live.com>
# MIT license
"""
Correct (counts) image for exposure by dividing the exposure map.
References
----------
* Chandra Memo: An Introduction to Exposure Map
http://cxc.harvard.edu/ciao/download/doc/expmap_intro.ps
* CIAO: Single Chip ACIS Exposure Map and Exposure-corrected Image
http://cxc.harvard.edu/ciao/threads/expmap_acis_single/
* CIAO: Multiple Chip ACIS Exposure Map and Exposure-corrected Image
http://cxc.harvard.edu/ciao/threads/expmap_acis_multi/
"""
import os
import argparse
import subprocess
import logging
from _context import acispy
from acispy.manifest import get_manifest
from acispy.pfiles import setup_pfiles
from acispy.image import get_xygrid
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)
def threshold_image(infile, outfile, expmap, cut="1.5%", clobber=False):
"""
The strongly variable exposure near the edge of a dithered field
may produce "hot" pixels when divided into an image. Therefore,
apply a threshold to the image pixels that cuts the pixels with
value of exposure less than the threshold.
"""
logger.info("Threshold cut the image: cut=%s" % cut)
clobber = "yes" if clobber else "no"
subprocess.check_call(["punlearn", "dmimgthresh"])
subprocess.check_call([
"dmimgthresh", "infile=%s" % infile,
"outfile=%s" % outfile, "expfile=%s" % expmap,
"cut=%s" % cut,
"clobber=%s" % clobber
])
def correct_exposure(infile, outfile, expmap, clobber=False):
"""
The strongly variable exposure near the edge of a dithered field
may produce "hot" pixels when divided into an image. Therefore,
apply a threshold to the image pixels that cuts the pixels with
value of exposure less than the threshold.
"""
logger.info("Correct the image for exposure ...")
clobber = "yes" if clobber else "no"
subprocess.check_call(["punlearn", "dmimgcalc"])
subprocess.check_call([
"dmimgcalc", "infile=%s" % infile, "infile2=%s" % expmap,
"outfile=%s[PFLUX_IMAGE]" % outfile,
"operation=div",
"clobber=%s" % clobber
])
def main():
parser = argparse.ArgumentParser(
description="Make spectral-weighted exposure map")
parser.add_argument("-C", "--clobber", dest="clobber", action="store_true",
help="overwrite existing file")
parser.add_argument("-M", "--update-manifest", dest="update_manifest",
action="store_true",
help="update manifest with newly created images")
parser.add_argument("-i", "--infile", dest="infile", required=True,
help="input image file to apply exposure correction")
parser.add_argument("-e", "--expmap", dest="expmap",
help="exposure map (default: 'expmap' from manifest)")
parser.add_argument("-o", "--outfile", dest="outfile",
help="filename of output exposure-corrected image " +
"(default: append '_expcorr' to the base filename)")
args = parser.parse_args()
setup_pfiles(["dmimgcalc", "dmimgthresh"])
manifest = get_manifest()
if args.expmap:
expmap = args.expmap
else:
expmap = manifest.getpath("expmap", relative=True)
if args.outfile:
img_expcorr = args.outfile
else:
img_expcorr = os.path.splitext(args.infile)[0] + "_expcorr.fits"
img_thresh = os.path.splitext(args.infile)[0] + "_thresh.fits"
logger.info("infile: %s" % args.infile)
logger.info("expmap: %s" % expmap)
logger.info("output exposure-corrected image: %s" % img_expcorr)
logger.info("output threshold-cut counts image: %s" % img_thresh)
xygrid_infile = get_xygrid(args.infile)
xygrid_expmap = get_xygrid(expmap)
logger.info("%s:xygrid: %s" % (args.infile, xygrid_infile))
logger.info("%s:xygrid: %s" % (expmap, xygrid_expmap))
if xygrid_infile != xygrid_expmap:
raise ValueError("xygrid: input image and exposure map do not match")
threshold_image(infile=args.infile, outfile=img_thresh, expmap=expmap,
clobber=args.clobber)
correct_exposure(infile=img_thresh, outfile=img_expcorr,
expmap=expmap, clobber=args.clobber)
if args.update_manifest:
logger.info("Add newly created images to manifest ...")
key = "img_expcorr"
manifest.setpath(key, img_expcorr)
logger.info("Added '%s' to manifest: %s" % (key, manifest.get(key)))
key = "img_thresh"
manifest.setpath(key, img_thresh)
logger.info("Added '%s' to manifest: %s" % (key, manifest.get(key)))
if __name__ == "__main__":
main()
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