def raw_aperture_photometry(sci_path,
rms_path,
mask_path,
ra,
dec,
apply_calibration=False):
import photutils
from astropy.coordinates import SkyCoord
from astropy.io import fits
from astropy.table import vstack
from astropy.wcs import WCS
ra = np.atleast_1d(ra)
dec = np.atleast_1d(dec)
coord = SkyCoord(ra, dec, unit='deg')
with fits.open(sci_path, memmap=False) as shdu:
header = shdu[0].header
swcs = WCS(header)
scipix = shdu[0].data
with fits.open(rms_path, memmap=False) as rhdu:
rmspix = rhdu[0].data
with fits.open(mask_path, memmap=False) as mhdu:
maskpix = mhdu[0].data
apertures = photutils.SkyCircularAperture(coord, r=APERTURE_RADIUS)
phot_table = photutils.aperture_photometry(scipix,
apertures,
error=rmspix,
wcs=swcs)
pixap = apertures.to_pixel(swcs)
annulus_masks = pixap.to_mask(method='center')
maskpix = [annulus_mask.cutout(maskpix) for annulus_mask in annulus_masks]
magzp = header['MAGZP']
apcor = header[APER_KEY]
# check for invalid photometry on masked pixels
phot_table['flags'] = [
int(np.bitwise_or.reduce(m, axis=(0, 1))) for m in maskpix
]
phot_table['zp'] = magzp + apcor
phot_table['obsjd'] = header['OBSJD']
phot_table['filtercode'] = 'z' + header['FILTER'][-1]
# rename some columns
phot_table.rename_column('aperture_sum', 'flux')
phot_table.rename_column('aperture_sum_err', 'fluxerr')
return phot_table
def _get_apertures(grid):
# NOTE: we assume all apertures have the same radius
r = np.unique(grid.radiuses)
assert r.shape[0] == 1, "Regions have different radiuses!"
apertures = photutils.SkyCircularAperture(
SkyCoord(ra=grid.centers_ra * u.deg,
dec=grid.centers_dec * u.deg,
frame='icrs'), r[0] * u.arcsec)
return apertures
def test_recovered_flux_aperture(science_image):
with fits.open(science_image) as hdul:
header = hdul[0].header
wcs = WCS(header)
footprint = wcs.calc_footprint()
# realize fakes randomly throughout the footprint
rx = rng.uniform(size=N_FAKE)
ry = rng.uniform(size=N_FAKE)
# keep things bright
mag = rng.uniform(low=15, high=18, size=N_FAKE)
minra, mindec = footprint.min(axis=0)
maxra, maxdec = footprint.max(axis=0)
coord = SkyCoord(minra + (maxra - minra) * rx,
mindec + (maxdec - mindec) * ry,
unit='deg')
fakes.inject_psf(science_image, mag, coord)
with fits.open(science_image) as hdul:
data = hdul[-2].data
header = hdul[0].header
table = hdul[-1].data
# subtract off the background
sigma_clip = SigmaClip(sigma=3.0)
bkg = MedianBackground(sigma_clip)
bkg_val = bkg.calc_background(data)
bkgsub = data - bkg_val
APERTURE_RADIUS = 3 * u.pixel
for row in table:
ra, dec, mag = row['fake_ra'], row['fake_dec'], row['fake_mag']
coord = SkyCoord(ra, dec, unit='deg')
apertures = photutils.SkyCircularAperture(coord, r=APERTURE_RADIUS)
phot_table = photutils.aperture_photometry(bkgsub, apertures, wcs=wcs)
flux = phot_table['aperture_sum'][0]
assert abs(-2.5 * np.log10(flux) + header['MAGZP'] + header['APCOR4'] -
mag) < 0.05
def measure_backgrounds(cat_table, ref_im):
"""
Measure the background for all the sources in cat_table, using
ref_im.
Parameters
----------
cat_table: astropy Table
the catalog in astropy table form, as loaded from a .gst.fits
photometry catalog
ref_im: imageHDU
fits image which will be used to estimate the background
Returns
-------
measurements: list of float
a metric for the background intensity at the star's position
(photometry / area)
mask: 2d ndarray of bool
an array containing a bool for each pixel of the image, True if
the pixel was ignored for the background calculations
"""
if not ref_im:
# Return a dumb value
return cat_table['F814W_CHI']
w = wcs.WCS(ref_im.header)
shp = ref_im.data.shape
inner_rad = 30 * units.pixel
outer_rad = inner_rad + 20 * units.pixel
mask_rad = inner_rad
# More elaborate way using an actual image (do not care about the
# filter for the moment, just take the image (which was given on the
# command line) at face value)
ra = cat_table['RA']
dec = cat_table['DEC']
c = astropy.coordinates.SkyCoord(ra * units.degree, dec * units.degree)
# Annuli, of which the counts per surface area will be used as
# background measurements
annuli = pu.SkyCircularAnnulus(c, r_in=inner_rad, r_out=outer_rad)
area = annuli.to_pixel(w).area()
# A mask to make sure that no sources end up in the background
# calculation
circles = pu.SkyCircularAperture(c, mask_rad)
source_masks = circles.to_pixel(w).to_mask()
mask_union = np.zeros(shp)
for i, ap_mask in enumerate(source_masks):
data_slices = list(ap_mask.bbox.slices)
# These slices go outside of the box sometimes! In that case we
# will override the slices on both sides.
# Default slices (go over the whole mask)
mask_slices = [slice(None, None), slice(None, None)]
# Adjust the slices for x and y if necessary
for j in range(2):
# DATA: . . a b c d e f
# index - - 0 1 2 3 4 5
# ---------------
# MASK: - + + + -
# index 0 1 2 3 4
# --> DATA_SLICE [0:stop]
# --> MASK_SLICE [2:]
data_start = data_slices[j].start
if data_start < 0:
# Move the start from negative n to zero
data_slices[j] = slice(0, data_slices[j].stop)
# Move the start from 0 to positive n
mask_slices[j] = slice(-data_start, mask_slices[j].stop)
# --> we slice over the part of the small mask that
# falls on the positive side of the axis
data_stop = data_slices[j].stop
if data_stop > shp[j]:
overflow = data_stop - shp[j]
# Move the stop 'overflow' to shp[j]
data_slices[j] = slice(data_slices[j].start, shp[j])
# Move the stop to 'overflow' pixels from the end
mask_slices[j] = slice(mask_slices[j].start, -overflow)
# --> slice over the part that falls below the maximum
mask_union[data_slices] += ap_mask.data[mask_slices]
# Threshold
mask_union = mask_union > 0
phot = pu.aperture_photometry(ref_im.data, annuli, wcs=w, mask=mask_union)
return phot['aperture_sum'] / area, mask_union
outf.writeto('dendrograms_min1mJy_diff1mJy_mask_pruned.fits', clobber=True)
for image, name in ((contfile,''), (radio_image,'KUband')):
data = image[0].data.squeeze()
mywcs = wcs.WCS(image[0].header).celestial
keys = ['{1}cont_flux{0}arcsec'.format(rr.value, name) for rr in radii]
columns = {k:[] for k in (keys)}
log.info("Doing aperture photometry on {0}".format(name))
for ii, row in enumerate(ProgressBar(pruned_ppcat)):
size = max(radii)*2.2
xc,yc = row['x_cen'], row['y_cen']
position = coordinates.SkyCoord(xc, yc, frame='fk5', unit=(u.deg,u.deg))
cutout = Cutout2D(data, position, size, mywcs, mode='partial')
for rr in radii:
aperture = photutils.SkyCircularAperture(positions=position,
r=rr).to_pixel(cutout.wcs)
aperture_data = photutils.aperture_photometry(data=cutout.data,
apertures=aperture,
method='exact')
flux_jybeam = aperture_data[0]['aperture_sum']
#flux_jybeam_average = flux_jybeam / aperture.area()
#flux_jysr_average = flux_jybeam_average / beam.sr.value
#flux_jysr = flux_jysr_average * aperture.area()
#flux_jy = (flux_jysr * (pixel_scale**2).to(u.sr).value)
columns['{1}cont_flux{0}arcsec'.format(rr.value, name)].append(flux_jybeam/ppbeam)
for k in columns:
if k not in pruned_ppcat.keys():
pruned_ppcat.add_column(Column(name=k, data=columns[k]))
for k in pruned_ppcat.colnames:
def aperture_photometry(calibratable,
ra,
dec,
apply_calibration=False,
assume_background_subtracted=False,
use_cutout=False,
direct_load=None):
import photutils
from astropy.coordinates import SkyCoord
from astropy.io import fits
from astropy.table import vstack
from astropy.wcs import WCS
ra = np.atleast_1d(ra)
dec = np.atleast_1d(dec)
coord = SkyCoord(ra, dec, unit='deg')
if not use_cutout:
wcs = calibratable.wcs
apertures = photutils.SkyCircularAperture(coord, r=APERTURE_RADIUS)
# something that is photometerable implements mask, background, and wcs
if not assume_background_subtracted:
pixels_bkgsub = calibratable.background_subtracted_image.data
else:
pixels_bkgsub = calibratable.data
bkgrms = calibratable.rms_image.data
mask = calibratable.mask_image.data
phot_table = photutils.aperture_photometry(pixels_bkgsub,
apertures,
error=bkgrms,
wcs=wcs)
phot_table['zp'] = calibratable.header['MAGZP'] + calibratable.header[
'APCOR4']
phot_table['obsjd'] = calibratable.header['OBSJD']
phot_table['filtercode'] = 'z' + calibratable.header['FILTER'][-1]
pixap = apertures.to_pixel(wcs)
annulus_masks = pixap.to_mask(method='center')
maskpix = [
annulus_mask.cutout(mask.data) for annulus_mask in annulus_masks
]
else:
phot_table = []
maskpix = []
for s in coord:
if direct_load is not None and 'sci' in direct_load:
sci_path = direct_load['sci']
else:
if assume_background_subtracted:
sci_path = calibratable.local_path
else:
sci_path = calibratable.background_subtracted_image.local_path
if direct_load is not None and 'mask' in direct_load:
mask_path = direct_load['mask']
else:
mask_path = calibratable.mask_image.local_path
if direct_load is not None and 'rms' in direct_load:
rms_path = direct_load['rms']
else:
rms_path = calibratable.rms_image.local_path
with fits.open(sci_path, memmap=True) as f:
wcs = WCS(f[0].header)
pixcoord = wcs.all_world2pix([[s.ra.deg, s.dec.deg]], 0)[0]
pixx, pixy = pixcoord
nx = calibratable.header['NAXIS1']
ny = calibratable.header['NAXIS2']
xmin = max(0, pixx - 1.5 * APERTURE_RADIUS.value)
xmax = min(nx, pixx + 1.5 * APERTURE_RADIUS.value)
ymin = max(0, pixy - 1.5 * APERTURE_RADIUS.value)
ymax = min(ny, pixy + 1.5 * APERTURE_RADIUS.value)
ixmin = int(np.floor(xmin))
ixmax = int(np.ceil(xmax))
iymin = int(np.floor(ymin))
iymax = int(np.ceil(ymax))
ap = photutils.CircularAperture([pixx - ixmin, pixy - iymin],
APERTURE_RADIUS.value)
# something that is photometerable implements mask, background, and wcs
with fits.open(sci_path, memmap=True) as f:
pixels_bkgsub = f[0].data[iymin:iymax, ixmin:ixmax]
with fits.open(rms_path, memmap=True) as f:
bkgrms = f[0].data[iymin:iymax, ixmin:ixmax]
with fits.open(mask_path, memmap=True) as f:
mask = f[0].data[iymin:iymax, ixmin:ixmax]
pt = photutils.aperture_photometry(pixels_bkgsub, ap, error=bkgrms)
annulus_mask = ap.to_mask(method='center')
mp = annulus_mask.cutout(mask.data)
maskpix.append(mp)
phot_table.append(pt)
phot_table = vstack(phot_table)
if apply_calibration:
magzp = calibratable.header['MAGZP']
apcor = calibratable.header[APER_KEY]
phot_table['mag'] = -2.5 * np.log10(
phot_table['aperture_sum']) + magzp + apcor
phot_table['magerr'] = 1.0826 * phot_table[
'aperture_sum_err'] / phot_table['aperture_sum']
# check for invalid photometry on masked pixels
phot_table['flags'] = [
int(np.bitwise_or.reduce(m, axis=(0, 1))) for m in maskpix
]
# rename some columns
phot_table.rename_column('aperture_sum', 'flux')
phot_table.rename_column('aperture_sum_err', 'fluxerr')
return phot_table
def measure_backgrounds(cat_table, ref_im, mask_radius, ann_width, cat_filter):
"""
Measure the background for all the sources in cat_table, using
ref_im.
Parameters
----------
cat_table: astropy Table
the catalog in astropy table form, as loaded from a .gst.fits
photometry catalog
ref_im: imageHDU
fits image which will be used to estimate the background
mask_radius : float
radius (in pixels) of mask for catalog sources
ann_width : float
width of annulus (in pixels) for calculating background around each catalog source
cat_filter : list or None
If list: Two elements in which the first is a filter (e.g. 'F475W') and
the second is a magnitude. Catalog entries with [filter]_VEGA > mag
will not be masked.
If None: all catalog entries will be considered.
Returns
-------
measurements: list of float
a metric for the background intensity at the star's position
(photometry / area)
"""
w = wcs.WCS(ref_im.header)
shp = ref_im.data.shape
inner_rad = mask_radius * units.pixel
outer_rad = inner_rad + ann_width * units.pixel
mask_rad = inner_rad
# More elaborate way using an actual image (do not care about the
# filter for the moment, just take the image (which was given on the
# command line) at face value)
ra = cat_table['RA']
dec = cat_table['DEC']
c = astropy.coordinates.SkyCoord(ra * units.degree, dec * units.degree)
# Annuli, of which the counts per surface area will be used as
# background measurements
annuli = pu.SkyCircularAnnulus(c, r_in=inner_rad, r_out=outer_rad)
area = annuli.to_pixel(w).area()
# A mask to make sure that no sources end up in the background
# calculation
if cat_filter is None:
circles = pu.SkyCircularAperture(c, mask_rad)
else:
circles = pu.SkyCircularAperture(c[ cat_table[cat_filter[0]+'_VEGA'] < float(cat_filter[1]) ], mask_rad)
source_masks = circles.to_pixel(w).to_mask()
mask_union = np.zeros(shp)
for i, ap_mask in enumerate(source_masks):
# the masks have a bounding box which we need to take into
# account. Here we will calculate the overlap between the mask
# and the image (important if the mask is near the edge, so that
# the box might go outside of it).
data_slices = list(ap_mask.bbox.slices)
# These slices go outside of the box sometimes! In that case we
# will override the slices on both sides.
# Default slices (go over the whole mask)
mask_slices = [slice(None, None), slice(None, None)]
# Adjust the slices in each dimension
for j in range(2):
# DATA: . . a b c d e f
# index - - 0 1 2 3 4 5
# ---------------
# MASK: - + + + -
# index 0 1 2 3 4
# --> DATA_SLICE [0:stop]
# --> MASK_SLICE [2:]
data_start = data_slices[j].start
if data_start < 0:
# Move the start from negative n to zero
data_slices[j] = slice(0, data_slices[j].stop)
# Move the start from 0 to positive n
mask_slices[j] = slice(-data_start, mask_slices[j].stop)
# --> we slice over the part of the small mask that
# falls on the positive side of the axis
data_stop = data_slices[j].stop
if data_stop > shp[j]:
overflow = data_stop - shp[j]
# Move the stop 'overflow' to shp[j]
data_slices[j] = slice(data_slices[j].start, shp[j])
# Move the stop to 'overflow' pixels from the end
mask_slices[j] = slice(mask_slices[j].start, -overflow)
# --> slice over the part that falls below the maximum
mask_union[tuple(data_slices)] += ap_mask.data[tuple(mask_slices)]
# Threshold
mask_union = mask_union > 0
# also mask NaNs
mask_union[np.isnan(ref_im.data)] = True
# Save the masked reference image
hdu = fits.PrimaryHDU(np.where(mask_union, 0, ref_im.data), header=ref_im.header)
hdu.writeto('masked_reference_image.fits', overwrite=True)
# Do the measurements
phot = pu.aperture_photometry(ref_im.data, annuli, wcs=w, mask=mask_union)
return phot['aperture_sum'] / area
def funcdrz_aperture_photometry_on_crop(drz, obs, tar, source='qso', fp_image='drz_crop.fits', radii=([1., 2., 3., 4., ])*u.arcsec, stretch='linear', vmin=None, vmax=None):
""" measure aperture photometry of images
"""
s = drz.sources[source]
# wcs from drz.fits
w = wcs.WCS(fits.getheader(drz.directory+'drz.fits', 1))
# read crop
fp = s.directory+fp_image
fp_root = os.path.splitext(fp)[0]
data = fits.getdata(fp)
# define aperture
pos_sky = ac.SkyCoord(s.ra, s.dec, frame='icrs', unit='deg')
apt_sky = [pu.SkyCircularAperture(pos_sky, r=r) for r in radii]
apt_pix = [apt_sky.to_pixel(wcs=w) for apt_sky in apt_sky]
# transform from drz.fits pix coordinate to crop pix coordinate
pos_pix_crop = apt_pix[0].positions[0] - np.array([s.x, s.y]) + np.array(data.shape[::-1])//2
apertures_pix_crop = copy.copy(apt_pix)
for aperture in apertures_pix_crop:
aperture.positions = np.array([pos_pix_crop])
phot = at.Table(pu.aperture_photometry(data, apertures_pix_crop))
phot['xcenter'].unit = None
phot['ycenter'].unit = None
# reorganize phot table
phot.remove_column('id')
phot.rename_column('xcenter', 'xc_drzcrop')
phot.rename_column('ycenter', 'yc_drzcrop')
phot['xc_drz'] = apt_pix[0].positions[0][0]
phot['yc_drz'] = apt_pix[0].positions[0][1]
phot['ra'] = s.ra
phot['dec'] = s.dec
phot['fn_image'] = fp_image
cols = ['fn_image', 'ra', 'dec', 'xc_drz', 'yc_drz', 'xc_drzcrop', 'yc_drzcrop', ]
if len(radii) == 1:
cols += ['aperture_sum']
else:
cols += ['aperture_sum_'+str(i) for i in range(len(radii))]
phot = phot[cols]
# write photometric results
phot.write(fp_root+'_aphot.csv', overwrite=True)
# write radii csv
radii_df = pd.DataFrame({'tag': ['aperture_sum_'+str(i) for i in range(len(radii))],
'radii': [str(radii[i]) for i in range(len(radii))]})
radii_df = radii_df[['tag','radii']]
radii_df.to_csv('radii.csv', index=False)
# visual
v = tinyfit.visual.visual(fp)
v.plot(fn_out=fp_root+'_aphot.pdf', colorbar=True, vmin=vmin, vmax=vmax, stretch=stretch)
for a in apertures_pix_crop:
a.plot()
plt.savefig(fp_root+'_aphot.pdf')
plt.close()