def merge_gsaoi_objcats(ad, cull_sources=False):
"""
This function takes an AstroDataGsaoi object and combines the OBJCATs on
the 4 extensions into a single Table, while also adding the static-
distortion-corrected coordinates based on the WCS on each extension.
Parameters
----------
ad : AstroData
input AstroDataGsaoi object with OBJCATs
cull_sources : bool
include only non-saturated point-like sources?
Returns
-------
Table : merged OBJCATs with static-distortion-corrected coords added
"""
# If we're not going to clip the OBJCATs we still need an iterable
# for the main loop
clipped_objcats = gt.clip_sources(ad) if cull_sources else ad
objcats = []
for index, (ext, objcat) in enumerate(zip(ad, clipped_objcats)):
if cull_sources and not objcat:
continue
elif not cull_sources:
try:
objcat = ext.OBJCAT.copy()
except AttributeError:
continue
objcat['ext_index'] = index
static = ext.wcs.get_transform(ext.wcs.input_frame, "static")
objcat['X_STATIC'], objcat['Y_STATIC'] = static(
objcat['X_IMAGE'] - 1, objcat['Y_IMAGE'] - 1)
objcats.append(objcat)
return table.vstack(objcats, metadata_conflicts='silent')
def test_clip_sources(self):
ad = astrodata.open(os.path.join(TESTDATAPATH, 'GSAOI',
'S20150110S0208_sourcesDetected.fits'))
ret = gt.clip_sources(ad)
# Only check the x-values, which are all unique in the table
correct_x_values = [(1174.81,), (200.874,1616.33),
(915.444,1047.15,1106.54,1315.22), (136.063,957.848)]
for rv, cv in zip([objcat['x'].data for objcat in ret], correct_x_values):
assert len(rv) == len(cv)
for a, b in zip(np.sort(rv), np.sort(cv)):
assert abs(a-b) < 0.01
def _correlate_sources(ad1, ad2, delta=None, firstPass=10, cull_sources=False):
"""
This function takes sources from the OBJCAT extensions in two
images and attempts to correlate them. It returns a list of
reference source positions and their correlated image source
positions.
:param ad1: reference image
:type ad1: AstroData instance
:param ad2: input image
:type ad2: AstroData instance
:param delta: maximum distance in pixels to allow a match. If
left as None, it will attempt to find an appropriate
number (recommended).
:type delta: float
:param firstPass: estimated maximum distance between correlated
sources. This distance represents the expected
mismatch between the WCSs of the input images.
:type firstPass: float
:param cull_sources: flag to indicate whether to reject sources that
are insufficiently star-like
:type cull_sources: bool
"""
log = gemLog.getGeminiLog()
# If desired, clip out the most star-like sources in the OBJCAT
if cull_sources:
good_src_1 = gt.clip_sources(ad1)[("SCI", 1)]
good_src_2 = gt.clip_sources(ad2)[("SCI", 1)]
if len(good_src_1) < 3 or len(good_src_2) < 3:
log.warning("Too few sources in culled list, using full set " "of sources")
x1 = ad1["OBJCAT"].data.field("X_IMAGE")
y1 = ad1["OBJCAT"].data.field("Y_IMAGE")
x2 = ad2["OBJCAT"].data.field("X_IMAGE")
y2 = ad2["OBJCAT"].data.field("Y_IMAGE")
else:
x1 = good_src_1["x"]
y1 = good_src_1["y"]
x2 = good_src_2["x"]
y2 = good_src_2["y"]
else:
# Otherwise, just get all sources
x1 = ad1["OBJCAT"].data.field("X_IMAGE")
y1 = ad1["OBJCAT"].data.field("Y_IMAGE")
x2 = ad2["OBJCAT"].data.field("X_IMAGE")
y2 = ad2["OBJCAT"].data.field("Y_IMAGE")
# get WCS from both images
wcs1 = pywcs.WCS(ad1["SCI"].header)
wcs2 = pywcs.WCS(ad2["SCI"].header)
# convert image 2 data to sky coordinates
ra2, dec2 = wcs2.wcs_pix2sky(x2, y2, 1)
# convert image 2 sky data to image 1 pixel coordinates
conv_x2, conv_y2 = wcs1.wcs_sky2pix(ra2, dec2, 1)
# find matches
ind1, ind2 = at.match_cxy(x1, conv_x2, y1, conv_y2, delta=delta, firstPass=firstPass, log=log)
if len(ind1) != len(ind2):
raise Errors.ScienceError("Mismatched arrays returned from match_cxy")
if len(ind1) < 1 or len(ind2) < 1:
return [[], []]
else:
obj_list = [zip(x1[ind1], y1[ind1]), zip(x2[ind2], y2[ind2])]
return obj_list
def adjustWCSToReference(self, adinputs=None, **params):
"""
This primitive registers images to a reference image by correcting
the relative error in their world coordinate systems. This is
preferably done via alignment of sources common to the reference
and input images but a fallback method that uses the header offsets
is also available, if there are too few sources to provide a robust
alignment, or if the initial WCSs are incorrect.
The alignment of sources is done via the KDTreeFitter, which does
not require a direct one-to-one mapping of sources between the
images. The alignment is performed in the pixel frame of each input
image, with sources in the reference image being transformed into
that frame via the existing WCS transforms. Therefore, whatever
transformation is required can simply be placed at the start of each
input image's WCS pipeline.
In order to use the direct mapping method, sources must have been
detected in the frame and attached to the AstroData instance in an
OBJCAT extension. This can be accomplished via the detectSources
primitive.
It is expected that the relative difference between the WCSs of
images to be combined should be quite small, so it may not be necessary
to allow rotation and scaling degrees of freedom when fitting the image
WCS to the reference WCS. However, if it is desired, the options
rotate and scale can be used to allow these degrees of freedom. Note
that these options refer to rotation/scaling of the WCS itself, not the
images. Significant rotation and scaling of the images themselves
will generally already be encoded in the WCS, and will be corrected for
when the images are aligned.
Parameters
----------
suffix: str
suffix to be added to output files
method: str ['sources' | 'offsets']
method to use to generate reference points. 'sources' uses sources
to align images, 'offsets' uses POFFSET and QOFFSET keywords
fallback: 'header' or None
backup method, if the primary one fails
first_pass: float
search radius (arcsec) for the initial alignment matching
min_sources: int
minimum number of matched sources required to apply a WCS shift
cull_sources: bool
remove sub-optimal (saturated and/or non-stellar) sources before
alignment?
rotate: bool
allow image rotation to align to reference image?
scale: bool
allow image scaling to align to reference image?
"""
warnings = {
"offsets": "Using header offsets for alignment",
None: "No WCS correction being performed"
}
log = self.log
log.debug(gt.log_message("primitive", self.myself(), "starting"))
timestamp_key = self.timestamp_keys[self.myself()]
if len(adinputs) <= 1:
log.warning("No correction will be performed, since at least two "
"input images are required for adjustWCSToReference")
return adinputs
if not all(len(ad) == 1 for ad in adinputs):
raise OSError("All input images must have only one extension.")
method = params["method"]
fallback = params["fallback"]
first_pass = params["first_pass"]
min_sources = params["min_sources"]
cull_sources = params["cull_sources"]
rotate = params["rotate"]
scale = params["scale"]
# Use first image in list as reference
adref = adinputs[0]
log.stdinfo(f"Reference image: {adref.filename}")
# Create a dummy WCS to facilitate future operations
if adref[0].wcs is None:
adref[0].wcs = gWCS([(cf.Frame2D(name="pixels"),
models.Identity(len(adref[0].shape))),
(cf.Frame2D(name="world"), None)])
try:
ref_objcat = adref[0].OBJCAT
except AttributeError:
log.warning(f"Reference image has no OBJCAT. {warnings[fallback]}")
method = fallback
else:
if len(ref_objcat) < min_sources and method == "sources":
log.warning(
f"Too few objects found in reference image {warnings[fallback]}"
)
method = fallback
if method is None:
return adinputs
adoutputs = [adref]
for ad in adinputs[1:]:
msg = ""
if method == "sources":
try:
objcat = ad[0].OBJCAT
except AttributeError:
msg = f"{ad.filename} image has no OBJCAT. "
else:
if len(objcat) < min_sources:
msg = f"{ad.filename} has too few sources. "
if msg or method == "offsets":
msg += warnings[fallback]
log.stdinfo(msg)
_create_wcs_from_offsets(ad, adref)
continue
# GNIRS WCS is dubious, so update WCS by using the ref
# image's WCS and the telescope offsets before alignment
#if ad.instrument() == 'GNIRS':
# log.stdinfo("Recomputing WCS for GNIRS from offsets")
# ad = _create_wcs_from_offsets(ad, adref)
log.fullinfo(f"Number of objects in {ad.filename}: {len(objcat)}")
log.stdinfo(
f"Cross-correlating sources in {adref.filename}, {ad.filename}"
)
pixscale = ad.pixel_scale()
if pixscale is None:
log.warning(f'Cannot determine pixel scale for {ad.filename}. '
f'Using a search radius of {first_pass} pixels.')
firstpasspix = first_pass
else:
firstpasspix = first_pass / pixscale
incoords = (objcat['X_IMAGE'].data - 1, objcat['Y_IMAGE'].data - 1)
refcoords = (ref_objcat['X_IMAGE'].data - 1,
ref_objcat['Y_IMAGE'].data - 1)
if cull_sources:
good_src1 = gt.clip_sources(ad)[0]
good_src2 = gt.clip_sources(adref)[0]
if len(good_src1) < min_sources or len(
good_src2) < min_sources:
log.warning(
"Too few sources in culled list, using full set "
"of sources")
else:
incoords = (good_src1["x"] - 1, good_src1["y"] - 1)
refcoords = (good_src2["x"] - 1, good_src2["y"] - 1)
try:
t_init = adref[0].wcs.forward_transform | ad[
0].wcs.backward_transform
except AttributeError: # for cases with no defined WCS
pass
else:
refcoords = t_init(*refcoords)
# The code used to start with a translation-only model, but this
# isn't helpful if there's a sizeable rotation or scaling, so
# let's just try to do the whole thing (if the user asks) and
# see what happens.
transform, obj_list = find_alignment_transform(
incoords,
refcoords,
transform=None,
shape=ad[0].shape,
search_radius=firstpasspix,
rotate=rotate,
scale=scale,
return_matches=True)
n_corr = len(obj_list[0])
if n_corr < min_sources + rotate + scale:
log.warning(f"Too few correlated objects ({n_corr}). "
"Setting rotate=False, scale=False")
transform, obj_list = find_alignment_transform(
incoords,
refcoords,
transform=None,
shape=ad[0].shape,
search_radius=firstpasspix,
rotate=False,
scale=False,
return_matches=True)
n_corr = len(obj_list[0])
log.stdinfo(f"Number of correlated sources: {n_corr}")
log.fullinfo("\nMatched sources:")
log.fullinfo(" Ref. x Ref. y Img. x Img. y\n {}".format("-" *
31))
for img, ref in zip(*obj_list):
log.fullinfo(" {:7.2f} {:7.2f} {:7.2f} {:7.2f}".format(
*ref, *img))
log.stdinfo("")
if n_corr < min_sources:
log.warning("Too few correlated sources found. "
"{}".format(warnings[fallback]))
if fallback == 'offsets':
_create_wcs_from_offsets(ad, adref)
adoutputs.append(ad)
continue
try:
ad[0].wcs.insert_transform(ad[0].wcs.input_frame,
transform,
after=True)
except AttributeError: # no WCS
ad[0].wcs = gWCS([(cf.Frame2D(name="pixels"), transform),
(cf.Frame2D(name="world"), None)])
adoutputs.append(ad)
# Timestamp and update filenames
for ad in adoutputs:
gt.mark_history(ad, primname=self.myself(), keyword=timestamp_key)
ad.update_filename(suffix=params["suffix"], strip=True)
return adoutputs
def align_images_from_wcs(adinput,
adref,
cull_sources=False,
transform=None,
min_sources=1,
search_radius=10,
match_radius=2,
rotate=False,
scale=False,
full_wcs=False,
brute=True,
return_matches=False):
"""
This function takes two images (an input image, and a reference image) and
works out the modifications needed to the WCS of the input images so that
the world coordinates of its OBJCAT sources match the world coordinates of
the OBJCAT sources in the reference image. This is done by modifying the
WCS of the input image and mapping the reference image sources to pixels
in the input image via the reference image WCS (fixed) and the input image
WCS. As such, in the nomenclature of the fitting routines, the pixel
positions of the input image's OBJCAT become the "reference" sources,
while the converted positions of the reference image's OBJCAT are the
"input" sources.
Parameters
----------
adinput: AstroData
input AD whose pixel shift is requested
adref: AstroData
reference AD image
transform: Transform/None
existing transformation (if None, will do brute search)
cull_sources: bool
limit matched sources to "good" (i.e., stellar) objects
min_sources: int
minimum number of sources to use for cross-correlation
search_radius: float
size of search box (in pixels)
match_radius: float
matching radius for objects (in pixels)
rotate: bool
add a rotation to the alignment transform?
scale: bool
add a magnification to the alignment transform?
full_wcs: bool
use the two images' WCSs to reproject the reference image's coordinates
onto the input image's pixel plane, rather than just align the OBJCAT
coordinates?
brute: bool
perform brute (landscape) search first?
return_matches: bool
return a list of matched objects as well as the Transform?
Returns
-------
matches: 2 lists
OBJCAT sources in input and reference that are matched
WCS: new WCS for input image
"""
log = logutils.get_logger(__name__)
if len(adinput) * len(adref) != 1:
log.warning('Can only match single-extension images')
return None
try:
input_objcat = adinput[0].OBJCAT
ref_objcat = adref[0].OBJCAT
except AttributeError:
log.warning('Both input images must have object catalogs')
return None
if len(input_objcat) < min_sources or len(ref_objcat) < min_sources:
log.warning("Too few sources in one or both images. Cannot align.")
return None
largest_dimension = max(*adinput[0].shape, *adref[0].shape)
# Values larger than these result in errors of >1 pixel
mag_threshold = 1. / largest_dimension
rot_threshold = np.degrees(mag_threshold)
# OK, we can proceed
incoords = (input_objcat['X_IMAGE'].data - 1,
input_objcat['Y_IMAGE'].data - 1)
refcoords = (ref_objcat['X_IMAGE'].data - 1,
ref_objcat['Y_IMAGE'].data - 1)
if cull_sources:
good_src1 = gt.clip_sources(adinput)[0]
good_src2 = gt.clip_sources(adref)[0]
if len(good_src1) < min_sources or len(good_src2) < min_sources:
log.warning("Too few sources in culled list, using full set "
"of sources")
else:
incoords = (good_src1["x"] - 1, good_src1["y"] - 1)
refcoords = (good_src2["x"] - 1, good_src2["y"] - 1)
# Set up the initial model
magnification, rotation = 1, 0 # May be overridden later
try:
t = adref[0].wcs.forward_transform | adinput[0].wcs.backward_transform
except AttributeError: # for cases with no defined WCS
t = None
if full_wcs:
log.warning(
"Cannot determine WCS information: setting full_wcs=False")
full_wcs = False
if full_wcs:
refcoords = t(*refcoords)
elif transform is None and t is not None:
transform = t.inverse
if transform is None:
transform = models.Identity(2)
# We always refactor the transform (if provided) in a prescribed way so
# as to ensure it's fittable and not overly weird
affine = adwcs.calculate_affine_matrices(transform, adinput[0].shape)
m_init = models.Shift(affine.offset[1]) & models.Shift(affine.offset[0])
# This is approximate since the affine matrix might have differential
# scaling and a shear
magnification = np.sqrt(abs(np.linalg.det(affine.matrix)))
rotation = np.degrees(
np.arctan2(affine.matrix[1, 0] - affine.matrix[0, 1],
affine.matrix[0, 0] + affine.matrix[1, 1]))
m_init.offset_0.bounds = (m_init.offset_0 - search_radius,
m_init.offset_0 + search_radius)
m_init.offset_1.bounds = (m_init.offset_1 - search_radius,
m_init.offset_1 + search_radius)
m_rotate = Rotate2D(rotation)
if rotate:
m_rotate.angle.bounds = (rotation - 5, rotation + 5)
m_init = m_rotate | m_init
elif abs(rotation) > rot_threshold:
m_rotate.angle.fixed = True
m_init = m_rotate | m_init
log.warning("A rotation of {:.3f} degrees is expected but the "
"rotation is fixed".format(rotation))
m_magnify = Scale2D(magnification)
if scale:
m_magnify.factor.bounds = (magnification - 0.05, magnification + 0.05)
m_init = m_magnify | m_init
elif abs(magnification - 1) > mag_threshold:
m_magnify.factor.fixed = True
m_init = m_magnify | m_init
log.warning("A magnification of {:.4f} is expected but the "
"magnification is fixed".format(magnification))
# Perform the fit
m_final = fit_model(m_init, incoords, refcoords, sigma=10, brute=brute)
if return_matches:
matched = match_sources(m_final(*incoords),
refcoords,
radius=match_radius)
ind2 = np.where(matched >= 0)
ind1 = matched[ind2]
obj_list = [[], []] if len(ind1) < 1 else [
np.array(list(zip(*incoords)))[ind2],
np.array(list(zip(*refcoords)))[ind1]
]
return obj_list, m_final
return m_final
def align_images_from_wcs(adinput,
adref,
transform=None,
cull_sources=False,
min_sources=1,
search_radius=10,
rotate=False,
scale=False,
full_wcs=False,
return_matches=False):
"""
This function takes two images (an input image, and a reference image) and
works out the modifications needed to the WCS of the input images so that
the world coordinates of its OBJCAT sources match the world coordinates of
the OBJCAT sources in the reference image. This is done by modifying the
WCS of the input image and mapping the reference image sources to pixels
in the input image via the reference image WCS (fixed) and the input image
WCS. As such, in the nomenclature of the fitting routines, the pixel
positions of the input image's OBJCAT become the "reference" sources,
while the converted positions of the reference image's OBJCAT are the
"input" sources.
Parameters
----------
adinput: AstroData
input AD whose pixel shift is requested
adref: AstroData
reference AD image
transform: Transform/None
existing transformation (if None, will do brute search)
cull_sources: bool
limit matched sources to "good" (i.e., stellar) objects
min_sources: int
minimum number of sources to use for cross-correlation
search_radius: float
size of search box (in arcseconds)
rotate: bool
add a rotation to the alignment transform?
scale: bool
add a magnification to the alignment transform?
full_wcs: bool
use recomputed WCS at each iteration, rather than modify the positions
in pixel space?
return_matches: bool
return a list of matched objects as well as the Transform?
Returns
-------
matches: 2 lists
OBJCAT sources in input and reference that are matched
WCS: new WCS for input image
"""
log = logutils.get_logger(__name__)
if len(adinput) * len(adref) != 1:
log.warning('Can only match single-extension images')
return None
try:
input_objcat = adinput[0].OBJCAT
ref_objcat = adref[0].OBJCAT
except AttributeError:
log.warning('Both input images must have object catalogs')
return None
if len(input_objcat) < min_sources or len(ref_objcat) < min_sources:
log.warning("Too few sources in one or both images. Cannot align.")
return None
# OK, we can proceed
incoords = (input_objcat['X_IMAGE'].data, input_objcat['Y_IMAGE'].data)
refcoords = (ref_objcat['X_IMAGE'], ref_objcat['Y_IMAGE'])
if cull_sources:
good_src1 = gt.clip_sources(adinput)[0]
good_src2 = gt.clip_sources(adref)[0]
if len(good_src1) < min_sources or len(good_src2) < min_sources:
log.warning("Too few sources in culled list, using full set "
"of sources")
else:
incoords = (good_src1["x"], good_src1["y"])
refcoords = (good_src2["x"], good_src2["y"])
# Nomenclature here is that the ref_transform transforms the reference
# OBJCAT coords immutably, and then the fit_transform is the fittable
# thing we're trying to get to map those to the input OBJCAT coords
ref_transform = Transform(Pix2Sky(WCS(adref[0].hdr)))
# pixel_range = max(adinput[0].data.shape)
if full_wcs:
# fit_transform = Transform(Pix2Sky(WCS(adinput[0].hdr), factor=pixel_range, factor_scale=pixel_range, angle_scale=pixel_range/57.3).inverse)
fit_transform = Transform(
Pix2Sky(WCS(adinput[0].hdr)).rename('WCS').inverse)
fit_transform.angle.fixed = not rotate
fit_transform.factor.fixed = not scale
else:
ref_transform.append(Pix2Sky(WCS(adinput[0].hdr)).inverse)
fit_transform = Transform.create2d(translation=(0, 0),
rotation=0 if rotate else None,
magnification=1 if scale else None,
shape=adinput[0].shape)
# Copy parameters across. We don't simply start with the provided
# transform, because we may be moving from a geometric one to WCS
if transform is not None:
for param in fit_transform.param_names:
if param in transform.param_names:
setattr(fit_transform, param, getattr(transform, param))
fit_transform.add_bounds('x_offset', search_radius)
fit_transform.add_bounds('y_offset', search_radius)
if rotate:
fit_transform.add_bounds('angle', 5.)
if scale:
fit_transform.add_bounds('factor', 0.05)
# Do the fit, and update the transform with the fitted parameters
transformed_ref_coords = ref_transform(*refcoords)
refine = (transform is not None)
fitted_model = fit_model(fit_transform.asModel(),
transformed_ref_coords,
incoords,
sigma=10,
tolerance=1e-6,
brute=not refine)
fit_transform.replace(fitted_model)
if return_matches:
matched = match_sources(fitted_model(*transformed_ref_coords),
incoords,
radius=1.0)
ind2 = np.where(matched >= 0)
ind1 = matched[ind2]
obj_list = [[], []] if len(ind1) < 1 else [
np.array(list(zip(*incoords)))[ind1],
np.array(list(zip(*refcoords)))[ind2]
]
return obj_list, fit_transform
return fit_transform
def align_images_from_wcs(adinput, adref, first_pass=10, cull_sources=False,
initial_shift = (0,0), min_sources=1, rotate=False,
scale=False, full_wcs=False, refine=False,
tolerance=0.1, return_matches=False):
"""
This function takes two images (an input image, and a reference image) and
works out the modifications needed to the WCS of the input images so that
the world coordinates of its OBJCAT sources match the world coordinates of
the OBJCAT sources in the reference image. This is done by modifying the
WCS of the input image and mapping the reference image sources to pixels
in the input image via the reference image WCS (fixed) and the input image
WCS. As such, in the nomenclature of the fitting routines, the pixel
positions of the input image's OBJCAT become the "reference" sources,
while the converted positions of the reference image's OBJCAT are the
"input" sources.
Parameters
----------
adinput: AstroData
input AD whose pixel shift is requested
adref: AstroData
reference AD image
first_pass: float
size of search box (in arcseconds)
cull_sources: bool
limit matched sources to "good" (i.e., stellar) objects
min_sources: int
minimum number of sources to use for cross-correlation, depending on the
instrument used
rotate: bool
add a rotation to the alignment transform?
scale: bool
add a magnification to the alignment transform?
full_wcs: bool
use recomputed WCS at each iteration, rather than modify the positions
in pixel space?
refine: bool
only do a simplex fit to refine an existing transformation?
(requires full_wcs=True). Also ignores return_matches
tolerance: float
matching requirement (in pixels)
return_matches: bool
return a list of matched objects?
Returns
-------
matches: 2 lists
OBJCAT sources in input and reference that are matched
WCS: new WCS for input image
"""
log = logutils.get_logger(__name__)
if len(adinput) * len(adref) != 1:
log.warning('Can only match single-extension images')
return None
if not (hasattr(adinput[0], 'OBJCAT') and hasattr(adref[0], 'OBJCAT')):
log.warning('Both input images must have object catalogs')
return None
if cull_sources:
good_src1 = gt.clip_sources(adinput)[0]
good_src2 = gt.clip_sources(adref)[0]
if len(good_src1) < min_sources or len(good_src2) < min_sources:
log.warning("Too few sources in culled list, using full set "
"of sources")
x1, y1 = adinput[0].OBJCAT['X_IMAGE'], adinput[0].OBJCAT['Y_IMAGE']
x2, y2 = adref[0].OBJCAT['X_IMAGE'], adref[0].OBJCAT['Y_IMAGE']
else:
x1, y1 = good_src1["x"], good_src1["y"]
x2, y2 = good_src2["x"], good_src2["y"]
else:
x1, y1 = adinput[0].OBJCAT['X_IMAGE'], adinput[0].OBJCAT['Y_IMAGE']
x2, y2 = adref[0].OBJCAT['X_IMAGE'], adref[0].OBJCAT['Y_IMAGE']
# convert reference positions to sky coordinates
ra2, dec2 = WCS(adref[0].hdr).all_pix2world(x2, y2, 1)
func = match_catalogs if return_matches else align_catalogs
if full_wcs:
# Set up the (inverse) Pix2Sky transform with appropriate scalings
pixel_range = max(adinput[0].data.shape)
transform = Pix2Sky(WCS(adinput[0].hdr), factor=pixel_range,
factor_scale=pixel_range, angle=0.0,
angle_scale=pixel_range/57.3, direction=-1)
x_offset, y_offset = initial_shift
transform.x_offset = x_offset
transform.y_offset = y_offset
transform.angle.fixed = not rotate
transform.factor.fixed = not scale
if refine:
fit_it = KDTreeFitter()
final_model = fit_it(transform, (ra2, dec2), (x1, y1),
method='Nelder-Mead',
options={'xtol': tolerance, 'ftol': 100.0})
log.stdinfo(_show_model(final_model, 'Refined transformation'))
return final_model
else:
transform.x_offset.bounds = (x_offset-first_pass, x_offset+first_pass)
transform.y_offset.bounds = (y_offset-first_pass, y_offset+first_pass)
if rotate:
# 5.73 degrees
transform.angle.bounds = (-0.1*pixel_range, 0.1*pixel_range)
if scale:
# 5% scaling
transform.factor.bounds = (0.95*pixel_range, 1.05*pixel_range)
# map input positions (in reference frame) to reference positions
func_ret = func(ra2, dec2, x1, y1, model_guess=transform,
tolerance=tolerance)
else:
x2a, y2a = WCS(adinput[0].hdr).all_world2pix(ra2, dec2, 1)
func_ret = func(x2a, y2a, x1, y1, model_guess=None,
translation=initial_shift,
translation_range=first_pass,
rotation_range=5.0 if rotate else None,
magnification_range=0.05 if scale else None,
tolerance=tolerance)
if return_matches:
matched, transform = func_ret
ind2 = np.where(matched >= 0)
ind1 = matched[ind2]
obj_list = [[], []] if len(ind1) < 1 else [list(zip(x1[ind1], y1[ind1])),
list(zip(x2[ind2], y2[ind2]))]
return obj_list, transform
else:
return func_ret
def align_images_from_wcs(adinput,
adref,
first_pass=10,
cull_sources=False,
initial_shift=(0, 0),
min_sources=1,
rotate=False,
scale=False,
full_wcs=False,
refine=False,
tolerance=0.1,
return_matches=False):
"""
This function takes two images (an input image, and a reference image) and
works out the modifications needed to the WCS of the input images so that
the world coordinates of its OBJCAT sources match the world coordinates of
the OBJCAT sources in the reference image. This is done by modifying the
WCS of the input image and mapping the reference image sources to pixels
in the input image via the reference image WCS (fixed) and the input image
WCS. As such, in the nomenclature of the fitting routines, the pixel
positions of the input image's OBJCAT become the "reference" sources,
while the converted positions of the reference image's OBJCAT are the
"input" sources.
Parameters
----------
adinput: AstroData
input AD whose pixel shift is requested
adref: AstroData
reference AD image
first_pass: float
size of search box (in arcseconds)
cull_sources: bool
limit matched sources to "good" (i.e., stellar) objects
min_sources: int
minimum number of sources to use for cross-correlation, depending on the
instrument used
rotate: bool
add a rotation to the alignment transform?
scale: bool
add a magnification to the alignment transform?
full_wcs: bool
use recomputed WCS at each iteration, rather than modify the positions
in pixel space?
refine: bool
only do a simplex fit to refine an existing transformation?
(requires full_wcs=True). Also ignores return_matches
tolerance: float
matching requirement (in pixels)
return_matches: bool
return a list of matched objects?
Returns
-------
matches: 2 lists
OBJCAT sources in input and reference that are matched
WCS: new WCS for input image
"""
log = logutils.get_logger(__name__)
if len(adinput) * len(adref) != 1:
log.warning('Can only match single-extension images')
return None
if not (hasattr(adinput[0], 'OBJCAT') and hasattr(adref[0], 'OBJCAT')):
log.warning('Both input images must have object catalogs')
return None
if cull_sources:
good_src1 = gt.clip_sources(adinput)[0]
good_src2 = gt.clip_sources(adref)[0]
if len(good_src1) < min_sources or len(good_src2) < min_sources:
log.warning("Too few sources in culled list, using full set "
"of sources")
x1, y1 = adinput[0].OBJCAT['X_IMAGE'], adinput[0].OBJCAT['Y_IMAGE']
x2, y2 = adref[0].OBJCAT['X_IMAGE'], adref[0].OBJCAT['Y_IMAGE']
else:
x1, y1 = good_src1["x"], good_src1["y"]
x2, y2 = good_src2["x"], good_src2["y"]
else:
x1, y1 = adinput[0].OBJCAT['X_IMAGE'], adinput[0].OBJCAT['Y_IMAGE']
x2, y2 = adref[0].OBJCAT['X_IMAGE'], adref[0].OBJCAT['Y_IMAGE']
# convert reference positions to sky coordinates
ra2, dec2 = WCS(adref[0].hdr).all_pix2world(x2, y2, 1)
func = match_catalogs if return_matches else align_catalogs
if full_wcs:
# Set up the (inverse) Pix2Sky transform with appropriate scalings
pixel_range = max(adinput[0].data.shape)
transform = Pix2Sky(WCS(adinput[0].hdr),
factor=pixel_range,
factor_scale=pixel_range,
angle=0.0,
angle_scale=pixel_range / 57.3,
direction=-1)
x_offset, y_offset = initial_shift
transform.x_offset = x_offset
transform.y_offset = y_offset
transform.angle.fixed = not rotate
transform.factor.fixed = not scale
if refine:
fit_it = KDTreeFitter()
final_model = fit_it(transform, (ra2, dec2), (x1, y1),
method='Nelder-Mead',
options={
'xtol': tolerance,
'ftol': 100.0
})
log.stdinfo(_show_model(final_model, 'Refined transformation'))
return final_model
else:
transform.x_offset.bounds = (x_offset - first_pass,
x_offset + first_pass)
transform.y_offset.bounds = (y_offset - first_pass,
y_offset + first_pass)
if rotate:
# 5.73 degrees
transform.angle.bounds = (-0.1 * pixel_range,
0.1 * pixel_range)
if scale:
# 5% scaling
transform.factor.bounds = (0.95 * pixel_range,
1.05 * pixel_range)
# map input positions (in reference frame) to reference positions
func_ret = func(ra2,
dec2,
x1,
y1,
model_guess=transform,
tolerance=tolerance)
else:
x2a, y2a = WCS(adinput[0].hdr).all_world2pix(ra2, dec2, 1)
func_ret = func(x2a,
y2a,
x1,
y1,
model_guess=None,
translation=initial_shift,
translation_range=first_pass,
rotation_range=5.0 if rotate else None,
magnification_range=0.05 if scale else None,
tolerance=tolerance)
if return_matches:
matched, transform = func_ret
ind2 = np.where(matched >= 0)
ind1 = matched[ind2]
obj_list = [[], []] if len(ind1) < 1 else [
list(zip(x1[ind1], y1[ind1])),
list(zip(x2[ind2], y2[ind2]))
]
return obj_list, transform
else:
return func_ret