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Add multi-source flux conservation test #177

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Mar 18, 2025
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Add multi-source flux conservation test #177

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Add multi-source flux conservation test
mcara Mar 18, 2025
bbdbe30
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mcara Mar 18, 2025
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25 changes: 25 additions & 0 deletions drizzle/tests/data/nrcb5_output_wcs_psr_0p55.hdr
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Original file line number Diff line number Diff line change
@@ -0,0 +1,25 @@
NAXIS = 2 / number of array dimensions
NAXIS1 = 3774
NAXIS2 = 3760
WCSAXES = 2 / Number of coordinate axes
WCSNAX1 = 3774
WCSNAX2 = 3760
WCSNAME = 'NRCB5-resampled-psr=0.55'
CRPIX1 = 1881.5 / Pixel coordinate of reference point
CRPIX2 = 1888.5 / Pixel coordinate of reference point
CD1_1 = -3.2887784263502E-06 / Coordinate transformation matrix element
CD1_2 = 9.0452124171947E-06 / Coordinate transformation matrix element
CD2_1 = 9.0452124170788E-06 / Coordinate transformation matrix element
CD2_2 = 3.2887784263487E-06 / Coordinate transformation matrix element
CUNIT1 = 'deg' / Units of coordinate increment and value
CUNIT2 = 'deg' / Units of coordinate increment and value
CTYPE1 = 'RA---TAN' / Right ascension, gnomonic projection
CTYPE2 = 'DEC--TAN' / Declination, gnomonic projection
CRVAL1 = 34.462181668953 / [deg] Coordinate value at reference point
CRVAL2 = -5.2370769627861 / [deg] Coordinate value at reference point
LONPOLE = 180.0 / [deg] Native longitude of celestial pole
LATPOLE = -5.2370769627861 / [deg] Native latitude of celestial pole
MJDREF = 0.0 / [d] MJD of fiducial time
RADESYS = 'ICRS' / Equatorial coordinate system
COMMENT pixel scale ratio: 0.55
END
25 changes: 25 additions & 0 deletions drizzle/tests/data/nrcb5_output_wcs_psr_1p0.hdr
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Original file line number Diff line number Diff line change
@@ -0,0 +1,25 @@
NAXIS = 2 / number of array dimensions
NAXIS1 = 2076
NAXIS2 = 2068
WCSAXES = 2 / Number of coordinate axes
WCSNAX1 = 2076
WCSNAX2 = 2068
WCSNAME = 'NRCB5-resampled-psr=1.0'
CRPIX1 = 1035.5 / Pixel coordinate of reference point
CRPIX2 = 1039.5 / Pixel coordinate of reference point
CD1_1 = -5.979597265673E-06 / Coordinate transformation matrix element
CD1_2 = 1.6445840712429E-05 / Coordinate transformation matrix element
CD2_1 = 1.644584071221E-05 / Coordinate transformation matrix element
CD2_2 = 5.9795972656895E-06 / Coordinate transformation matrix element
CUNIT1 = 'deg' / Units of coordinate increment and value
CUNIT2 = 'deg' / Units of coordinate increment and value
CTYPE1 = 'RA---TAN' / Right ascension, gnomonic projection
CTYPE2 = 'DEC--TAN' / Declination, gnomonic projection
CRVAL1 = 34.462186510947 / [deg] Coordinate value at reference point
CRVAL2 = -5.237071020123 / [deg] Coordinate value at reference point
LONPOLE = 180.0 / [deg] Native longitude of celestial pole
LATPOLE = -5.237071020123 / [deg] Native latitude of celestial pole
MJDREF = 0.0 / [d] MJD of fiducial time
RADESYS = 'ICRS' / Equatorial coordinate system
COMMENT pixel scale ratio: 1.0
END
25 changes: 25 additions & 0 deletions drizzle/tests/data/nrcb5_output_wcs_psr_1p2.hdr
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Original file line number Diff line number Diff line change
@@ -0,0 +1,25 @@
NAXIS = 2 / number of array dimensions
NAXIS1 = 1730
NAXIS2 = 1723
WCSAXES = 2 / Number of coordinate axes
WCSNAX1 = 1730
WCSNAX2 = 1723
WCSNAME = 'NRCB5-resampled-psr=1.2'
CRPIX1 = 862.5 / Pixel coordinate of reference point
CRPIX2 = 866.5 / Pixel coordinate of reference point
CD1_1 = -7.1755169028951E-06 / Coordinate transformation matrix element
CD1_2 = 1.9735008788012E-05 / Coordinate transformation matrix element
CD2_1 = 1.9735008787734E-05 / Coordinate transformation matrix element
CD2_2 = 7.1755169029068E-06 / Coordinate transformation matrix element
CUNIT1 = 'deg' / Units of coordinate increment and value
CUNIT2 = 'deg' / Units of coordinate increment and value
CTYPE1 = 'RA---TAN' / Right ascension, gnomonic projection
CTYPE2 = 'DEC--TAN' / Declination, gnomonic projection
CRVAL1 = 34.46219236569 / [deg] Coordinate value at reference point
CRVAL2 = -5.2370819342517 / [deg] Coordinate value at reference point
LONPOLE = 180.0 / [deg] Native longitude of celestial pole
LATPOLE = -5.2370819342517 / [deg] Native latitude of celestial pole
MJDREF = 0.0 / [d] MJD of fiducial time
RADESYS = 'ICRS' / Equatorial coordinate system
COMMENT pixel scale ratio: 1.2
END
63 changes: 63 additions & 0 deletions drizzle/tests/data/nrcb5_sip_wcs.hdr
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Original file line number Diff line number Diff line change
@@ -0,0 +1,63 @@
NAXIS = 2 / number of array dimensions
NAXIS1 = 2048
NAXIS2 = 2048
WCSAXES = 2 / Number of coordinate axes
WCSNAX1 = 2048
WCSNAX2 = 2048
WCSNAME = 'NCRB5-distorted'
CRPIX1 = 1024.5 / Pixel coordinate of reference point
CRPIX2 = 1024.5 / Pixel coordinate of reference point
CD1_1 = -5.9503404343539E-06 / Coordinate transformation matrix element
CD1_2 = 1.648275705369E-05 / Coordinate transformation matrix element
CD2_1 = 1.6413012543338E-05 / Coordinate transformation matrix element
CD2_2 = 6.0004968333255E-06 / Coordinate transformation matrix element
CUNIT1 = 'deg' / Units of coordinate increment and value
CUNIT2 = 'deg' / Units of coordinate increment and value
CTYPE1 = 'RA---TAN-SIP' / Right ascension, gnomonic projection
CTYPE2 = 'DEC--TAN-SIP' / Declination, gnomonic projection
CRVAL1 = 34.462141245715 / [deg] Coordinate value at reference point
CRVAL2 = -5.2370131013006 / [deg] Coordinate value at reference point
LONPOLE = 180.0 / [deg] Native longitude of celestial pole
LATPOLE = -5.2370131013006 / [deg] Native latitude of celestial pole
MJDREF = 0.0 / [d] MJD of fiducial time
RADESYS = 'ICRS' / Equatorial coordinate system
A_ORDER = 5
B_ORDER = 5
A_0_2 = 1.61277115051773E-06
A_0_3 = 1.73577114462509E-11
A_0_4 = 5.89952689299414E-15
A_0_5 = -9.2706016645490E-18
A_1_1 = -1.1751937758814E-05
A_1_2 = 1.73036803751169E-09
A_1_3 = -3.1289934897622E-14
A_1_4 = 3.06218671532168E-17
A_2_0 = -1.8926777088332E-06
A_2_1 = 1.03291495279138E-10
A_2_2 = 2.03368375378982E-14
A_2_3 = -4.4162900401209E-17
A_3_0 = 1.67914343216288E-09
A_3_1 = -5.4435048958724E-14
A_3_2 = 9.46275771964339E-17
A_4_0 = 7.41603692584866E-15
A_4_1 = -9.7176613274953E-18
A_5_0 = -2.6162006188010E-17
B_0_2 = -6.9663104269845E-06
B_0_3 = 1.69597092451221E-09
B_0_4 = -2.6284874597164E-14
B_0_5 = 3.79795310696409E-17
B_1_1 = -3.6577740533158E-06
B_1_2 = 8.02672477273099E-11
B_1_3 = -1.7478642466998E-14
B_1_4 = -2.7372755032689E-18
B_2_0 = 4.92018167812442E-06
B_2_1 = 1.69745602106894E-09
B_2_2 = 6.81819605498880E-15
B_2_3 = 7.20352111485166E-17
B_3_0 = 3.98424806886705E-12
B_3_1 = -5.3941905107867E-15
B_3_2 = -3.2098483024471E-17
B_4_0 = 2.16072939656730E-14
B_4_1 = -2.7836646857682E-17
B_5_0 = -1.8084499231992E-17
COMMENT Converted to FITS from JWST NRCB5 gwcs
END
91 changes: 61 additions & 30 deletions drizzle/tests/helpers.py
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Original file line number Diff line number Diff line change
@@ -56,40 +56,71 @@ def wcs_from_file(filename, ext=None, return_data=False, crpix_shift=None,
"""
full_file_name = os.path.join(DATA_DIR, filename)
path = os.path.join(DATA_DIR, full_file_name)
with fits.open(path) as hdu:
if ext is None:
for k, u in enumerate(hdu):

def get_shape(hdr):
naxis1 = hdr.get("WCSNAX1", hdr.get("NAXIS1"))
naxis2 = hdr.get("WCSNAX2", hdr.get("NAXIS2"))
if naxis1 is None or naxis2 is None:
return None
return (naxis2, naxis1)

def data_from_hdr(hdr, data=None, shape=None):
if data is not None:
return data
bitpix = hdr.get("BITPIX", -32)
dtype = fits.hdu.BITPIX2DTYPE[bitpix]
shape = get_shape(hdr) or shape
if shape is None:
return None
return np.zeros(shape, dtype=dtype)

if os.path.splitext(filename)[1] in [".hdr", ".txt"]:
hdul = None
hdr = fits.Header.fromfile(
path,
sep='\n',
endcard=False,
padding=False
)

else:
with fits.open(path) as fits_hdul:
hdul = fits.HDUList([hdu.copy() for hdu in fits_hdul])

if ext is None and hdul is not None:
for k, u in enumerate(hdul):
if "CTYPE1" in u.header:
ext = k
break

hdr = hdu[ext].header
naxis1 = hdr.get("WCSNAX1", hdr.get("NAXIS1"))
naxis2 = hdr.get("WCSNAX2", hdr.get("NAXIS2"))
if naxis1 is not None and naxis2 is not None:
shape = (naxis2, naxis1)
if hdu[ext].data is None:
hdu[ext].data = np.zeros(shape, dtype=np.float32)
else:
shape = None

if crpix_shift is not None and "CRPIX1" in hdr:
hdr["CRPIX1"] += crpix_shift[0]
hdr["CRPIX2"] += crpix_shift[1]

result = fits_wcs.WCS(hdr, hdu)
result.array_shape = shape

if wcs_type == "gwcs":
result = _gwcs_from_hst_fits_wcs(result)

if return_data:
result = (result, )
if not isinstance(return_data, (list, tuple)):
return_data = [ext]
for ext in return_data:
data = (hdu[ext].data, )
result = result + data
hdr = hdul[ext].header

if crpix_shift is not None and "CRPIX1" in hdr:
hdr["CRPIX1"] += crpix_shift[0]
hdr["CRPIX2"] += crpix_shift[1]

result = fits_wcs.WCS(hdr, hdul)
shape = get_shape(hdr)
result.array_shape = shape

if wcs_type == "gwcs":
result = _gwcs_from_hst_fits_wcs(result)

if return_data:
if hdul is None:
data = data_from_hdr(hdr, data=None, shape=shape)
return (result, data)

result = (result, )
if not isinstance(return_data, (list, tuple)):
return_data = [ext]
for ext in return_data:
data = data_from_hdr(
hdul[ext].header,
data=hdul[ext].data,
shape=shape
)
result = result + (data, )

return result

97 changes: 97 additions & 0 deletions drizzle/tests/test_resample.py
View file
Original file line number Diff line number Diff line change
@@ -5,6 +5,7 @@
import pytest

from astropy import wcs
from astropy.convolution import Gaussian2DKernel
from drizzle import cdrizzle, resample, utils

from .helpers import wcs_from_file
@@ -191,6 +192,56 @@ def make_grid_image(shape, spacing, value):
return output_image


@pytest.fixture(scope="module")
def nrcb5_stars():
full_file_name = os.path.join(DATA_DIR, "nrcb5_sip_wcs.hdr")
path = os.path.join(DATA_DIR, full_file_name)

wcs, data = wcs_from_file(path, return_data=True)
dq = np.zeros(data.shape, dtype=np.int32)

np.random.seed(0)

patch_size = 21
p2 = patch_size // 2
# add border so that resampled partial pixels can be isolated
# in the segmentation:
border = 4
pwb = patch_size + border

fwhm2sigma = 2.0 * math.sqrt(2.0 * math.log(2.0))

ny, nx = data.shape

stars = []

for yc in range(border + p2, ny - pwb, pwb):
for xc in range(border + p2, nx - pwb, pwb):
sl = np.s_[yc - p2:yc + p2 + 1, xc - p2:xc + p2 + 1]
flux = 1.0 + 99.0 * np.random.random()
if np.random.random() > 0.7:
# uniform image
psf = np.full((patch_size, patch_size), flux)
else:
# "star":
fwhm = 1.5 + 1.5 * np.random.random()
sigma = fwhm / fwhm2sigma

psf = flux * Gaussian2DKernel(
sigma,
x_size=patch_size,
y_size=patch_size
).array

flux = psf.sum()

data[sl] = psf
dq[sl] = 0
stars.append((xc, yc, flux, sl))

return data, dq, stars, wcs


def test_drizzle_defaults():
n = 200
in_shape = (n, n)
@@ -821,6 +872,52 @@ def test_flux_conservation_distorted(kernel, fc):
)


@pytest.mark.parametrize("kernel", ["square", "turbo", "point"])
@pytest.mark.parametrize("pscale_ratio", [0.55, 1.0, 1.2])
def test_flux_conservation_distorted_distributed_sources(nrcb5_stars, kernel, pscale_ratio):
""" test aperture photometry """
insci, dq, stars, wcs = nrcb5_stars

suffix = f"{pscale_ratio}".replace(".", "p")
output_wcs = wcs_from_file(f"nrcb5_output_wcs_psr_{suffix}.hdr")

pixmap = utils.calc_pixmap(
wcs,
output_wcs,
wcs.array_shape,
)

inwht = np.ones_like(insci) * (1 - dq)

driz = resample.Drizzle(
kernel=kernel,
out_shape=output_wcs.array_shape,
fillval=0.0,
)
driz.add_image(
insci,
exptime=1.0,
pixmap=pixmap,
weight_map=inwht,
scale=1,
)

# for efficiency, instead of doing this patch-by-patch,
# multiply resampled data by resampled image weight
out_data = driz.out_img * driz.out_wht

dim3 = (slice(None, None, None), )
for _, _, fin, sl in stars:
xyout = pixmap[sl + dim3]
xmin = int(np.floor(xyout[:, :, 0].min() - 0.5))
xmax = int(np.ceil(xyout[:, :, 0].max() + 1.5))
ymin = int(np.floor(xyout[:, :, 1].min() - 0.5))
ymax = int(np.ceil(xyout[:, :, 1].max() + 1.5))
fout = np.nansum(out_data[ymin:ymax, xmin:xmax])

assert np.allclose(fin, fout, rtol=1.0e-6, atol=0.0)


def test_drizzle_exptime():
n = 200
in_shape = (n, n)
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