matchFakeStars.py

Go to the documentation of this file.

"""
matchFakes.py
matches fakes based on position stored in the calibrated exposure image header
"""
 
import argparse
import re
import collections
 
import numpy as np
 
import lsst.daf.persistence as dafPersist
 
 
def getFakeSources(rootdir, dataId, tol=0.1):
    """Get list of sources which agree in position with fake ones with tol
    """
    butler = dafPersist.Butler(rootdir)
 
    sources = butler.get('src', dataId)
    cal_md = butler.get('calexp_md', dataId)
 
    # Get the X, Y locations of objects on the CCD
    srcX, srcY = sources.getX(), sources.getY()
    # Get the zeropoint
    zeropoint = 2.5*np.log10(cal_md.getScalar("FLUXMAG0"))
    # Get the PSF flux and its error
    flux, ferr = sources.getPsfFlux(), sources.getPsfFluxErr()
    # Convert them into magnitude and its error
    mag, merr = 2.5*np.log10(flux), 2.5/np.log(10)*(ferr/flux)
    mag = zeropoint - mag
 
    # X, Y locations of the fake stars
    fakeXY = collections.defaultdict(tuple)
    # Regular Expression
    fakename = re.compile('FAKE([0-9]+)')
    for card in cal_md.names():
        m = fakename.match(card)
        if m is not None:
            x, y = list(map(float, (cal_md.getScalar(card)).split(',')))
            fakeXY[int(m.group(1))] = (x, y)
 
    srcIndex = collections.defaultdict(list)
    for fid, fcoord in fakeXY.items():
        matched = ((np.abs(srcX-fcoord[0]) < tol) &
                   (np.abs(srcY-fcoord[1]) < tol))
        srcIndex[fid] = np.where(matched)[0]
 
    srcPsfMag = []
    srcPsfMerr = []
    matchX = []
    matchY = []
    for s in srcIndex.values():
        if len(s) > 0:
            ss = s[0]
            srcPsfMag.append(mag[ss])
            srcPsfMerr.append(merr[ss])
            matchX.append(srcX[ss])
            matchY.append(srcY[ss])
        else:
            srcPsfMag.append(0)
            srcPsfMerr.append(0)
            matchX.append(0)
            matchY.append(0)
 
    return srcIndex, fakeXY, matchX, matchY, srcPsfMag, srcPsfMerr
 
 
def main():
 
    # TODO: this should use the LSST/HSC conventions
    parser = argparse.ArgumentParser()
    parser.add_argument('rootDir', help='root dir of data repo')
    parser.add_argument('visit', help='id of visit', type=int)
    parser.add_argument('ccd', help='id of ccd', type=int)
    args = parser.parse_args()
 
    starIndex, fakeXY, matchX, matchY, starPsfMag, starPsfMerr = getFakeSources(args.rootDir,
                                                                                {'visit': args.visit,
                                                                                 'ccd': args.ccd})
 
    nInject = len(fakeXY)
    nMatch = len(np.argwhere(starPsfMag))
    print("# Number of Injected Stars : %d" % nInject)
    print("# Number of Matched  Stars : %d" % nMatch)
    print("# Visit = %d   CCD = %d" % (args.visit, args.ccd))
    print("# FakeX  FakeY  PSFMag  PSFMagErr  Deblend ")
 
    for i in range(nInject):
        if len(starIndex[i]) > 1:
            deblend = "blended"
        elif starPsfMag[i] > 0:
            deblend = "isolate"
        else:
            deblend = "nomatch"
 
        injectXY = fakeXY[i]
 
        print("%6.1d   %6.1d   %7.3f  %6.3f  %s" % (injectXY[0], injectXY[1],
                                                    starPsfMag[i], starPsfMerr[i], deblend))
 
 
if __name__ == '__main__':
    main()