def test_zero_input_weight(kernel):
"""
Test do_driz square kernel with grid
"""
# initialize input:
insci = np.ones((200, 400), dtype=np.float32)
inwht = np.ones((200, 400), dtype=np.float32)
inwht[:, 150:155] = 0
# initialize output:
outsci = np.zeros((210, 410), dtype=np.float32)
outwht = np.zeros((210, 410), dtype=np.float32)
outctx = np.zeros((210, 410), dtype=np.int32)
# define coordinate mapping:
pixmap = np.moveaxis(np.mgrid[1:201, 1:401][::-1], 0, -1)
# resample:
cdrizzle.tdriz(insci,
inwht,
pixmap,
outsci,
outwht,
outctx,
uniqid=1,
xmin=0,
xmax=400,
ymin=0,
ymax=200,
pixfrac=1,
kernel=kernel,
in_units='cps',
expscale=1,
wtscale=1,
fillstr='INDEF')
# check that no pixel with 0 weight has any counts:
assert np.sum(np.abs(outsci[(outwht == 0)])) == 0.0
def drizzlemask(inmask,
coord_map,
in_origin=(1, 1),
inwht=None,
compval=0.5,
comp='>',
out_shape=None,
out_origin=(1, 1),
scale=1.0,
pixfrac=1.0,
kernel='square',
dtype=None,
verbose=True):
"""
Resample a mask using "drizzle" algorithm and then apply thresholding to
resampled data to create "drizzled" mask.
Parameters
----------
inmask : numpy.ndarray
A 2D input mask to be resampled. Before being resampled, non-zero
elements in the mask are replaced with 1. This is peformed on a copy
of the `inmask` such that `inmask` itself is not modified.
coord_map : callable func(x, y)
A function that converts coordinates from the input mask's coordinate
frame to the desired output coordinate frame. Must be able to accept
1D vectors of coordinates and return a tuple of two 1D transformed
vectors.
in_origin : int, float, tuple, or list, optional
Spacial coordinates of the first pixel (i.e., `inmask[0,0]`) in the
input mask `inmask`. If a `list` or `tuple` is provided, then it must
have exactly two elements: (x_origin, y_origin). If a single value is
provided then both coordinates are set equal to the provided value.
inwht : numpy.ndarray, optional
A 2D numpy array containing the weights of pixels in the input mask.
Must have the same dimenstions as `inmask`. If none is supplied,
the weghting is set to one for all pixels.
compval : float, optional
The meaning of this parameter depends on the value of the `comp`
parameter. When `comp='>'`, `compval` has a meaning of a threshold and
indicates that values in the drizzled mask larger than `compval` should
be converted 1 in the binary output mask and values less or equal
to `compval` should be converted to 0.
comp : str, optional
Comparison operation to be performed on drizzled mask deciding if
a pixel in the output mask will be assigned 1 or 0. When the result
of comparison between the pixel value in the drizzled mask
and the value specified by the `compval` parameter is true,
the corresponding pixel in the output mask is assigned value 1 and
0 otherwise.
out_shape : tuple, list, optional
Specifies the shape of the output mask. This parameter must follow the
same convention as used in `numpy` for constructing arrays, that is,
it must be in the form (nrows,ncol), If set to `None`, the shape is
automatically determined so that all "True" (or 1) pixels in the input
mask fit in the output mask and the `out_origin` parameter is ignored.
out_origin : tuple, list, optional
Spacial coordinates of the first pixel (i.e., with indices `[0,0]`)
in the output mask. It must have exactly two elements:
(x_origin, y_origin). This parameter is ignored when `out_shape`=`None`.
scale : float, optional
The ratio of the output pixel scale to the input pixel scale.
pixfrac : float, optional
The fraction of a pixel that the pixel flux is confined to. The
default value of 1 has the pixel flux evenly spread across the image.
A value of 0.5 confines it to half a pixel in the linear dimension,
so the flux is confined to a quarter of the pixel area when the square
kernel is used.
kernel: str, optional
The name of the kernel used to combine the input. The choice of
kernel controls the distribution of flux over the kernel. The kernel
names are: "square", "gaussian", "point", "tophat", "turbo", "lanczos2",
and "lanczos3". The square kernel is the default.
dtype : numpy data-type, optional
Specifies the data type of the output mask. By default, the data-type
is inferred from the input data: when `inmask` is an `numpy` array of
integer or boolean data type, the output mask will be of the same type
as `inmask` and it will be `numpy.int8` otherwise.
verbose : bool, optional
Specifies whether to print information and warning messages.
Returns
-------
outmask : numpy.ndarray
Output binary (1 or 0) mask obtained by drizzling the input mask and
applying some threshold to the drizzled results. When `out_shape` is
`None` and the input mask is all 0, then the output mask will be
an empty array (with no elements).
out_origin : tuple
The coordinate of the first pixel in the `outmask` (i.e.,
`outmask[0,0]`). When `out_shape` is not `None` the value of
`out_origin` is passed directly from input. When `out_shape` is
`None` and the input mask is all 0, then `out_origin` will be
set to `(None, None)`.
"""
# verify that comparison operator is of supported type:
comp = (''.join(comp.split())).lower()
if comp not in _supported_comparisons:
raise ValueError("Unsupported comparison operator")
# set fillval:
fillval = ''
# set stepsize which indicates how often points at the perimeter of the
# input mask should be evaluated for the purpose of computing the output
# mask's shape:
stepsize = 1
# shape of the input mask:
inmask = np.asarray(inmask)
ny, nx = inmask.shape
# check that input weights (if provided) have the same shape as input mask:
if inwht is not None:
inwht = np.asarray(inwht, dtype=np.float32)
if inwht.shape != inmask.shape:
raise ValueError("'inwht' array must have the same shape as the "
"input mask array")
# make sure origins are iterable. If not - convert to tuples:
if not hasattr(in_origin, '__iter__'):
in_origin = (in_origin, in_origin)
else:
if len(in_origin) != 2:
raise ValueError("'in_origin' must be a either a list "
" or a tuple with two elements (coordinates)")
if out_origin is not None:
if not hasattr(out_origin, '__iter__'):
out_origin = (out_origin, out_origin)
else:
if len(out_origin) != 2:
raise ValueError("'out_origin' must be a either a list "
" or a tuple with two elements (coordinates)")
# data type of the input mask:
int_inmask = np.issubdtype(inmask.dtype, np.bool_) or \
np.issubdtype(inmask.dtype, np.integer)
# data type of the output result:
if dtype is None:
if int_inmask:
odtype = inmask.dtype
else:
odtype = np.int8
else:
odtype = dtype
# auto determine output image size?
auto_out_shape = out_shape is None
###############################################
## To save time on drizzling, find out ##
## how much of the input mask needs to be ##
## drizzled and how big the output may be. ##
###############################################
#1. find the bounding box of the non-zero pixels in the input mask:
xmin, xmax, mbnx, ymin, ymax, mbny = _min_box(inmask, int_inmask, True)
# if there are no non-zero pixels return an empty array (if out_shape==None)
# or an array of zeros (if out_shape!=None):
if mbnx * mbny == 0:
if auto_out_shape:
if verbose:
print("WARNING: No non-zero data have been found in the input "
"mask.\nWARNING: Output mask will be empty.")
return (np.empty((mbny, mbnx), dtype=odtype), (None, None))
else:
return (np.zeros((mbny, mbnx), dtype=odtype), out_origin)
#2. Expand the bounding box by 'ceil(scale)' pixel:
pad = int(np.ceil(scale))
xmin = max(0, xmin - pad)
xmax = min(nx - 1, xmax + pad)
ymin = max(0, ymin - pad)
ymax = min(ny - 1, ymax + pad)
minview = np.s_[ymin:ymax + 1, xmin:xmax + 1]
#3. create smallest-sized numpy.float32 copy of input mask with
# element values 0 or 1:
in_mask_min = np.zeros((ymax - ymin + 1, xmax - xmin + 1),
dtype=np.float32)
non_zeros = (inmask != 0)[minview]
in_mask_min[non_zeros] = 1.0
#4. find bounding box for output image:
# - compute the coordinates of the border
nintervals = np.ceil((xmax - xmin + 1) / stepsize)
xr = np.linspace(xmin - 0.5, xmax + 0.5, nintervals, dtype=np.float)
nxr = xr.shape[0]
yr = np.linspace(ymin - 0.5, ymax + 0.5, nintervals, dtype=np.float)[1:-1]
nyr = yr.shape[0]
npts = 2 * (nxr + nyr)
in_borderx = np.empty((npts, ), dtype=np.float)
in_bordery = np.empty((npts, ), dtype=np.float)
in_borderx[0:nxr] = xr
in_bordery[0:nxr] = ymin - 0.5
sl = np.s_[nxr:2 * nxr]
in_borderx[sl] = xr
in_bordery[sl] = ymax + 0.5
sl = np.s_[2 * nxr:2 * nxr + nyr]
in_borderx[sl] = xmin - 0.5
in_bordery[sl] = yr
sl = np.s_[2 * nxr + nyr:]
in_borderx[sl] = xmax + 0.5
in_bordery[sl] = yr
in_borderx += in_origin[0]
in_bordery += in_origin[1]
# - convert these coordinates to the output frame:
out_borderx, out_bordery = coord_map(in_borderx, in_bordery)
oxmin = np.amin(out_borderx)
oxmax = np.amax(out_borderx)
oymin = np.amin(out_bordery)
oymax = np.amax(out_bordery)
onx = int(np.ceil(oxmax - oxmin + 1))
ony = int(np.ceil(oymax - oymin + 1))
#5. if the shape of the output mask was not provided, use the minimal
# bounding box for output mask to define output shape:
if out_shape is None:
out_shape = (ony - 1, onx - 1)
out_origin = (oxmin + 0.5, oymin + 0.5)
else:
if not _do_rect_intersect(
oxmin, oxmax, oymin, oymax, out_origin[0] - 0.5,
out_origin[0] + out_shape[1] + 0.5, out_origin[1] - 0.5,
out_origin[1] + out_shape[0] + 0.5):
return (np.zeros(out_shape, dtype=odtype), out_origin)
#6. create pixel map:
# - create a list of pixel coordinates in the minimal mask:
in_y, in_x = np.indices(in_mask_min.shape, dtype=np.float)
in_x += xmin + in_origin[0]
in_y += ymin + in_origin[1]
# - compute pixel coordinates in the output (undistorted) frame:
out_x, out_y = coord_map(in_x, in_y)
# - create pixel map array:
pixmap = np.dstack((out_x, out_y))
#7. adjust pixmap coordinates to output origin:
pixmap -= np.asarray(out_origin, dtype=np.float)
##########################
## Drizzle the mask: ##
##########################
#1. create array for output drizzled mask and dummy arrays for output weight
# and context:
drizmask = np.zeros(out_shape, dtype=np.float32)
outwht = np.zeros(out_shape, dtype=np.float32)
outctx = np.zeros(out_shape, dtype=np.int32)
#2. create an array of weights if not provided:
if inwht is None:
in_wht_min = np.ones_like(in_mask_min)
else:
in_wht_min = inwht[minview]
#3. drizzle:
_vers, nmiss, nskip = cdrizzle.tdriz(input=in_mask_min,
weights=in_wht_min,
pixmap=pixmap,
output=drizmask,
counts=outwht,
context=outctx,
uniqid=1,
xmin=0,
xmax=0,
ymin=0,
ymax=0,
scale=scale,
pixfrac=pixfrac,
kernel=kernel,
in_units='cps',
expscale=1.0,
wtscale=1.0,
fillstr=fillval)
#4. apply threshold to the output mask:
if comp == '>' or comp == 'gt':
valid_pix = np.greater(drizmask, compval)
elif comp == '>=' or comp == 'ge':
valid_pix = np.greater_equal(drizmask, compval)
elif comp == '<' or comp == 'lt':
valid_pix = np.less(drizmask, compval)
elif comp == '<=' or comp == 'le':
valid_pix = np.less_equal(drizmask, compval)
elif comp == '==' or comp == 'eq':
valid_pix = np.isclose(drizmask, compval)
elif comp == '!=' or comp == '<>' or comp == 'ne':
valid_pix = np.logical_not(np.isclose(drizmask, compval))
else:
raise ValueError("Unsupported comparison operator")
#5. create output mask while trimming it to minimal boundng box:
if auto_out_shape:
oxminf, oxmaxf, ombnx, oyminf, oymaxf, ombny = _min_box(
valid_pix.astype(dtype=np.int8), True, False)
if ombnx * ombny == 0:
if auto_out_shape:
if verbose:
print("WARNING: No non-zero data have been found in the "
"output drizzled mask.\nWARNING: "
"Output mask will be empty.")
return (np.empty((ombny, ombnx), dtype=odtype), (None, None))
else:
return (np.zeros((ombny, ombnx), dtype=odtype), out_shape)
outmask = np.zeros((oymaxf - oyminf + 1, oxmaxf - oxminf + 1),
dtype=odtype)
outmask[valid_pix[oyminf:oymaxf + 1, oxminf:oxmaxf + 1]] = 1
else:
outmask = np.zeros_like(drizmask, dtype=odtype)
outmask[valid_pix] = 1
return (outmask, out_origin)
def drizzle_arrays(insci, inwht, input_wcs, output_wcs, outsci, outwht, outcon,
uniqid=1, xmin=None, xmax=None, ymin=None, ymax=None,
pixfrac=1.0, kernel='square', fillval="INDEF", wtscale=1.0):
"""
Low level routine for performing 'drizzle' operation on one image.
The interface is compatible with STScI code. All images are Python
ndarrays, instead of filenames. File handling (input and output) is
performed by the calling routine.
Parameters
----------
insci : 2d array
A 2d numpy array containing the input image to be drizzled.
inwht : 2d array
A 2d numpy array containing the pixel by pixel weighting.
Must have the same dimensions as insci. If none is supplied,
the weighting is set to one.
input_wcs : gwcs.WCS object
The world coordinate system of the input image.
output_wcs : gwcs.WCS object
The world coordinate system of the output image.
outsci : 2d array
A 2d numpy array containing the output image produced by
drizzling. On the first call it should be set to zero.
Subsequent calls it will hold the intermediate results. This
is modified in-place.
outwht : 2d array
A 2d numpy array containing the output counts. On the first
call it should be set to zero. On subsequent calls it will
hold the intermediate results. This is modified in-place.
outcon : 2d or 3d array, optional
A 2d or 3d numpy array holding a bitmap of which image was an input
for each output pixel. Should be integer zero on first call.
Subsequent calls hold intermediate results. This is modified
in-place.
uniqid : int, optional
The id number of the input image. Should be one the first time
this function is called and incremented by one on each subsequent
call.
xmin : float, optional
This and the following three parameters set a bounding rectangle
on the input image. Only pixels on the input image inside this
rectangle will have their flux added to the output image. Xmin
sets the minimum value of the x dimension. The x dimension is the
dimension that varies quickest on the image. If the value is zero,
no minimum will be set in the x dimension. All four parameters are
zero based, counting starts at zero.
xmax : float, optional
Sets the maximum value of the x dimension on the bounding box
of the input image. If the value is zero, no maximum will
be set in the x dimension, the full x dimension of the output
image is the bounding box.
ymin : float, optional
Sets the minimum value in the y dimension on the bounding box. The
y dimension varies less rapidly than the x and represents the line
index on the input image. If the value is zero, no minimum will be
set in the y dimension.
ymax : float, optional
Sets the maximum value in the y dimension. If the value is zero, no
maximum will be set in the y dimension, the full x dimension
of the output image is the bounding box.
pixfrac : float, optional
The fraction of a pixel that the pixel flux is confined to. The
default value of 1 has the pixel flux evenly spread across the image.
A value of 0.5 confines it to half a pixel in the linear dimension,
so the flux is confined to a quarter of the pixel area when the square
kernel is used.
kernel: str, optional
The name of the kernel used to combine the input. The choice of
kernel controls the distribution of flux over the kernel. The kernel
names are: "square", "gaussian", "point", "tophat", "turbo", "lanczos2",
and "lanczos3". The square kernel is the default.
fillval: str, optional
The value a pixel is set to in the output if the input image does
not overlap it. The default value of INDEF does not set a value.
Returns
-------
A tuple with three values: a version string, the number of pixels
on the input image that do not overlap the output image, and the
number of complete lines on the input image that do not overlap the
output input image.
"""
# Insure that the fillval parameter gets properly interpreted for use with tdriz
if util.is_blank(str(fillval)):
fillval = 'INDEF'
else:
fillval = str(fillval)
if (insci.dtype > np.float32):
insci = insci.astype(np.float32)
# Add input weight image if it was not passed in
if inwht is None:
inwht = np.ones_like(insci)
# Compute what plane of the context image this input would
# correspond to:
planeid = int((uniqid - 1) / 32)
# Check if the context image has this many planes
if outcon.ndim == 3:
nplanes = outcon.shape[0]
elif outcon.ndim == 2:
nplanes = 1
else:
nplanes = 0
if nplanes <= planeid:
raise IndexError("Not enough planes in drizzle context image")
# Alias context image to the requested plane if 3d
if outcon.ndim == 3:
outcon = outcon[planeid]
if xmin is xmax is ymin is ymax is None:
bb = input_wcs.bounding_box
((x1, x2), (y1, y2)) = bb
xmin = int(min(x1, x2))
ymin = int(min(y1, y2))
xmax = int(max(x1, x2))
ymax = int(max(y1, y2))
# Compute the mapping between the input and output pixel coordinates
# for use in drizzle.cdrizzle.tdriz
pixmap = resample_utils.calc_gwcs_pixmap(input_wcs, output_wcs, insci.shape)
log.debug(f"Pixmap shape: {pixmap[:,:,0].shape}")
log.debug(f"Input Sci shape: {insci.shape}")
log.debug(f"Output Sci shape: {outsci.shape}")
log.info(f"Drizzling {insci.shape} --> {outsci.shape}")
_vers, _nmiss, _nskip = cdrizzle.tdriz(
insci, inwht, pixmap,
outsci, outwht, outcon,
uniqid=uniqid,
xmin=xmin, xmax=xmax,
ymin=ymin, ymax=ymax,
pixfrac=pixfrac,
kernel=kernel,
in_units="cps",
expscale=1.0,
wtscale=wtscale,
fillstr=fillval
)
def dodrizzle(insci,
input_wcs,
inwht,
output_wcs,
outsci,
outwht,
outcon,
expin,
in_units,
wt_scl,
pscale_ratio=1.0,
uniqid=1,
xmin=0,
xmax=0,
ymin=0,
ymax=0,
pixfrac=1.0,
kernel='square',
fillval="INDEF"):
"""
Low level routine for performing 'drizzle' operation on one image.
The interface is compatible with STScI code. All images are Python
ndarrays, instead of filenames. File handling (input and output) is
performed by the calling routine.
Parameters
----------
insci : 2d array
A 2d numpy array containing the input image to be drizzled.
input_wcs : gwcs.WCS object
The world coordinate system of the input image.
inwht : 2d array
A 2d numpy array containing the pixel by pixel weighting.
Must have the same dimensions as insci. If none is supplied,
the weghting is set to one.
output_wcs : gwcs.WCS object
The world coordinate system of the output image.
outsci : 2d array
A 2d numpy array containing the output image produced by
drizzling. On the first call it should be set to zero.
Subsequent calls it will hold the intermediate results
outwht : 2d array
A 2d numpy array containing the output counts. On the first
call it should be set to zero. On subsequent calls it will
hold the intermediate results.
outcon : 2d or 3d array, optional
A 2d or 3d numpy array holding a bitmap of which image was an input
for each output pixel. Should be integer zero on first call.
Subsequent calls hold intermediate results.
expin : float
The exposure time of the input image, a positive number. The
exposure time is used to scale the image if the units are counts.
in_units : str
The units of the input image. The units can either be "counts"
or "cps" (counts per second.)
wt_scl : float
A scaling factor applied to the pixel by pixel weighting.
wcslin_pscale : float, optional
The pixel scale of the input image. Conceptually, this is the
linear dimension of a side of a pixel in the input image, but it
is not limited to this and can be set to change how the drizzling
algorithm operates.
uniqid : int, optional
The id number of the input image. Should be one the first time
this function is called and incremented by one on each subsequent
call.
xmin : float, optional
This and the following three parameters set a bounding rectangle
on the input image. Only pixels on the input image inside this
rectangle will have their flux added to the output image. Xmin
sets the minimum value of the x dimension. The x dimension is the
dimension that varies quickest on the image. If the value is zero,
no minimum will be set in the x dimension. All four parameters are
zero based, counting starts at zero.
xmax : float, optional
Sets the maximum value of the x dimension on the bounding box
of the input image. If the value is zero, no maximum will
be set in the x dimension, the full x dimension of the output
image is the bounding box.
ymin : float, optional
Sets the minimum value in the y dimension on the bounding box. The
y dimension varies less rapidly than the x and represents the line
index on the input image. If the value is zero, no minimum will be
set in the y dimension.
ymax : float, optional
Sets the maximum value in the y dimension. If the value is zero, no
maximum will be set in the y dimension, the full x dimension
of the output image is the bounding box.
pixfrac : float, optional
The fraction of a pixel that the pixel flux is confined to. The
default value of 1 has the pixel flux evenly spread across the image.
A value of 0.5 confines it to half a pixel in the linear dimension,
so the flux is confined to a quarter of the pixel area when the square
kernel is used.
kernel: str, optional
The name of the kernel used to combine the input. The choice of
kernel controls the distribution of flux over the kernel. The kernel
names are: "square", "gaussian", "point", "tophat", "turbo", "lanczos2",
and "lanczos3". The square kernel is the default.
fillval: str, optional
The value a pixel is set to in the output if the input image does
not overlap it. The default value of INDEF does not set a value.
Returns
-------
A tuple with three values: a version string, the number of pixels
on the input image that do not overlap the output image, and the
number of complete lines on the input image that do not overlap the
output input image.
"""
# Insure that the fillval parameter gets properly interpreted for use with tdriz
if util.is_blank(fillval):
fillval = 'INDEF'
else:
fillval = str(fillval)
if in_units == 'cps':
expscale = 1.0
else:
expscale = expin
# Add input weight image if it was not passed in
if (insci.dtype > np.float32):
insci = insci.astype(np.float32)
if inwht is None:
inwht = np.ones_like(insci)
if xmax is None or xmax == xmin:
xmax = insci.shape[1]
if ymax is None or ymax == ymin:
ymax = insci.shape[0]
# Compute what plane of the context image this input would
# correspond to:
planeid = int((uniqid - 1) / 32)
# Check if the context image has this many planes
if outcon.ndim == 3:
nplanes = outcon.shape[0]
elif outcon.ndim == 2:
nplanes = 1
else:
nplanes = 0
if nplanes <= planeid:
raise IndexError("Not enough planes in drizzle context image")
# Alias context image to the requested plane if 3d
if outcon.ndim == 3:
outcon = outcon[planeid]
# Compute the mapping between the input and output pixel coordinates
# for use in drizzle.cdrizzle.tdriz
pixmap = resample_utils.calc_gwcs_pixmap(input_wcs, output_wcs,
insci.shape)
# Temporary fix for tdriz not handling NaNs correctly; set NaNs to map
# off the output image and set the weight to zero
pixmap[np.isnan(pixmap)] = -10
# print("Number of NaNs: ", len(np.isnan(pixmap)) / 2)
# inwht[np.isnan(pixmap[:,:,0])] = 0.
log.debug("Pixmap shape: {}".format(pixmap[:, :, 0].shape))
log.debug("Input Sci shape: {}".format(insci.shape))
log.debug("Output Sci shape: {}".format(outsci.shape))
# y_mid = pixmap.shape[0] // 2
# x_mid = pixmap.shape[1] // 2
# print("x slice: ", pixmap[y_mid,:,0])
# print("y slice: ", pixmap[:,x_mid,1])
# print("insci: ", insci)
# Call 'drizzle' to perform image combination
log.info('Drizzling {} --> {}'.format(insci.shape, outsci.shape))
_vers, nmiss, nskip = cdrizzle.tdriz(insci,
inwht,
pixmap,
outsci,
outwht,
outcon,
uniqid=uniqid,
xmin=xmin,
xmax=xmax,
ymin=ymin,
ymax=ymax,
scale=pscale_ratio,
pixfrac=pixfrac,
kernel=kernel,
in_units=in_units,
expscale=expscale,
wtscale=wt_scl,
fillstr=fillval)
return _vers, nmiss, nskip
def dodrizzle(insci, input_wcs, inwht,
output_wcs, outsci, outwht, outcon,
expin, in_units, wt_scl,
pscale_ratio=1.0, uniqid=1,
xmin=0, xmax=0, ymin=0, ymax=0,
pixfrac=1.0, kernel='square', fillval="INDEF"):
"""
Low level routine for performing 'drizzle' operation.on one image.
The interface is compatible with STScI code. All images are Python
ndarrays, instead of filenames. File handling (input and output) is
performed by the calling routine.
Parameters
----------
insci : 2d array
A 2d numpy array containing the input image to be drizzled.
it is an error to not supply an image.
input_wcs : 2d array
The world coordinate system of the input image.
inwht : 2d array
A 2d numpy array containing the pixel by pixel weighting.
Must have the same dimensions as insci. If none is supplied,
the weghting is set to one.
output_wcs : wcs
The world coordinate system of the output image.
outsci : 2d array
A 2d numpy array containing the output image produced by
drizzling. On the first call it should be set to zero.
Subsequent calls it will hold the intermediate results
outwht : 2d array
A 2d numpy array containing the output counts. On the first
call it should be set to zero. On subsequent calls it will
hold the intermediate results.
outcon : 2d or 3d array, optional
A 2d or 3d numpy array holding a bitmap of which image was an input
for each output pixel. Should be integer zero on first call.
Subsequent calls hold intermediate results.
expin : float
The exposure time of the input image, a positive number. The
exposure time is used to scale the image if the units are counts.
in_units : str
The units of the input image. The units can either be "counts"
or "cps" (counts per second.)
wt_scl : float
A scaling factor applied to the pixel by pixel weighting.
wcslin_pscale : float, optional
The pixel scale of the input image. Conceptually, this is the
linear dimension of a side of a pixel in the input image, but it
is not limited to this and can be set to change how the drizzling
algorithm operates.
uniqid : int, optional
The id number of the input image. Should be one the first time
this function is called and incremented by one on each subsequent
call.
xmin : float, optional
This and the following three parameters set a bounding rectangle
on the input image. Only pixels on the input image inside this
rectangle will have their flux added to the output image. Xmin
sets the minimum value of the x dimension. The x dimension is the
dimension that varies quickest on the image. If the value is zero,
no minimum will be set in the x dimension. All four parameters are
zero based, counting starts at zero.
xmax : float, optional
Sets the maximum value of the x dimension on the bounding box
of the input image. If the value is zero, no maximum will
be set in the x dimension, the full x dimension of the output
image is the bounding box.
ymin : float, optional
Sets the minimum value in the y dimension on the bounding box. The
y dimension varies less rapidly than the x and represents the line
index on the input image. If the value is zero, no minimum will be
set in the y dimension.
ymax : float, optional
Sets the maximum value in the y dimension. If the value is zero, no
maximum will be set in the y dimension, the full x dimension
of the output image is the bounding box.
pixfrac : float, optional
The fraction of a pixel that the pixel flux is confined to. The
default value of 1 has the pixel flux evenly spread across the image.
A value of 0.5 confines it to half a pixel in the linear dimension,
so the flux is confined to a quarter of the pixel area when the square
kernel is used.
kernel: str, optional
The name of the kernel used to combine the input. The choice of
kernel controls the distribution of flux over the kernel. The kernel
names are: "square", "gaussian", "point", "tophat", "turbo", "lanczos2",
and "lanczos3". The square kernel is the default.
fillval: str, optional
The value a pixel is set to in the output if the input image does
not overlap it. The default value of INDEF does not set a value.
Returns
-------
A tuple with three values: a version string, the number of pixels
on the input image that do not overlap the output image, and the
number of complete lines on the input image that do not overlap the
output input image.
"""
# Insure that the fillval parameter gets properly interpreted for use with tdriz
if util.is_blank(fillval):
fillval = 'INDEF'
else:
fillval = str(fillval)
if in_units == 'cps':
expscale = 1.0
else:
expscale = expin
# Add input weight image if it was not passed in
if (insci.dtype > np.float32):
insci = insci.astype(np.float32)
if inwht is None:
inwht = np.ones_like(insci)
if xmax is None or xmax == xmin:
xmax = insci.shape[1]
if ymax is None or ymax == ymin:
ymax = insci.shape[0]
# Compute what plane of the context image this input would
# correspond to:
planeid = int((uniqid - 1) / 32)
# Check if the context image has this many planes
if outcon.ndim == 3:
nplanes = outcon.shape[0]
elif outcon.ndim == 2:
nplanes = 1
else:
nplanes = 0
if nplanes <= planeid:
raise IndexError("Not enough planes in drizzle context image")
# Alias context image to the requested plane if 3d
if outcon.ndim == 3:
outcon = outcon[planeid]
# Compute the mapping between the input and output pixel coordinates
pixmap = resample_utils.calc_gwcs_pixmap(input_wcs, output_wcs)
#
# Call 'drizzle' to perform image combination
# This call to 'cdriz.tdriz' uses the new C syntax
#
_vers, nmiss, nskip = cdrizzle.tdriz(
insci, inwht, pixmap, outsci, outwht, outcon,
uniqid=uniqid, xmin=xmin, xmax=xmax,
ymin=ymin, ymax=ymax, scale=pscale_ratio, pixfrac=pixfrac,
kernel=kernel, in_units=in_units, expscale=expscale,
wtscale=wt_scl, fillstr=fillval)
return _vers, nmiss, nskip
def drizzlemask(inmask, coord_map, in_origin=(1,1), inwht=None,
compval=0.5, comp='>',
out_shape=None, out_origin=(1,1), scale=1.0,
pixfrac=1.0, kernel='square', dtype=None,
verbose=True):
"""
Resample a mask using "drizzle" algorithm and then apply thresholding to
resampled data to create "drizzled" mask.
Parameters
----------
inmask : numpy.ndarray
A 2D input mask to be resampled. Before being resampled, non-zero
elements in the mask are replaced with 1. This is peformed on a copy
of the `inmask` such that `inmask` itself is not modified.
coord_map : callable func(x, y)
A function that converts coordinates from the input mask's coordinate
frame to the desired output coordinate frame. Must be able to accept
1D vectors of coordinates and return a tuple of two 1D transformed
vectors.
in_origin : int, float, tuple, or list, optional
Spacial coordinates of the first pixel (i.e., `inmask[0,0]`) in the
input mask `inmask`. If a `list` or `tuple` is provided, then it must
have exactly two elements: (x_origin, y_origin). If a single value is
provided then both coordinates are set equal to the provided value.
inwht : numpy.ndarray, optional
A 2D numpy array containing the weights of pixels in the input mask.
Must have the same dimenstions as `inmask`. If none is supplied,
the weghting is set to one for all pixels.
compval : float, optional
The meaning of this parameter depends on the value of the `comp`
parameter. When `comp='>'`, `compval` has a meaning of a threshold and
indicates that values in the drizzled mask larger than `compval` should
be converted 1 in the binary output mask and values less or equal
to `compval` should be converted to 0.
comp : str, optional
Comparison operation to be performed on drizzled mask deciding if
a pixel in the output mask will be assigned 1 or 0. When the result
of comparison between the pixel value in the drizzled mask
and the value specified by the `compval` parameter is true,
the corresponding pixel in the output mask is assigned value 1 and
0 otherwise.
out_shape : tuple, list, optional
Specifies the shape of the output mask. This parameter must follow the
same convention as used in `numpy` for constructing arrays, that is,
it must be in the form (nrows,ncol), If set to `None`, the shape is
automatically determined so that all "True" (or 1) pixels in the input
mask fit in the output mask and the `out_origin` parameter is ignored.
out_origin : tuple, list, optional
Spacial coordinates of the first pixel (i.e., with indices `[0,0]`)
in the output mask. It must have exactly two elements:
(x_origin, y_origin). This parameter is ignored when `out_shape`=`None`.
scale : float, optional
The ratio of the output pixel scale to the input pixel scale.
pixfrac : float, optional
The fraction of a pixel that the pixel flux is confined to. The
default value of 1 has the pixel flux evenly spread across the image.
A value of 0.5 confines it to half a pixel in the linear dimension,
so the flux is confined to a quarter of the pixel area when the square
kernel is used.
kernel: str, optional
The name of the kernel used to combine the input. The choice of
kernel controls the distribution of flux over the kernel. The kernel
names are: "square", "gaussian", "point", "tophat", "turbo", "lanczos2",
and "lanczos3". The square kernel is the default.
dtype : numpy data-type, optional
Specifies the data type of the output mask. By default, the data-type
is inferred from the input data: when `inmask` is an `numpy` array of
integer or boolean data type, the output mask will be of the same type
as `inmask` and it will be `numpy.int8` otherwise.
verbose : bool, optional
Specifies whether to print information and warning messages.
Returns
-------
outmask : numpy.ndarray
Output binary (1 or 0) mask obtained by drizzling the input mask and
applying some threshold to the drizzled results. When `out_shape` is
`None` and the input mask is all 0, then the output mask will be
an empty array (with no elements).
out_origin : tuple
The coordinate of the first pixel in the `outmask` (i.e.,
`outmask[0,0]`). When `out_shape` is not `None` the value of
`out_origin` is passed directly from input. When `out_shape` is
`None` and the input mask is all 0, then `out_origin` will be
set to `(None, None)`.
"""
# verify that comparison operator is of supported type:
comp = (''.join(comp.split())).lower()
if comp not in _supported_comparisons:
raise ValueError("Unsupported comparison operator")
# set fillval:
fillval = ''
# set stepsize which indicates how often points at the perimeter of the
# input mask should be evaluated for the purpose of computing the output
# mask's shape:
stepsize = 1
# shape of the input mask:
inmask = np.asarray(inmask)
ny, nx = inmask.shape
# check that input weights (if provided) have the same shape as input mask:
if inwht is not None:
inwht = np.asarray(inwht, dtype=np.float32)
if inwht.shape != inmask.shape:
raise ValueError("'inwht' array must have the same shape as the "
"input mask array")
# make sure origins are iterable. If not - convert to tuples:
if not hasattr(in_origin, '__iter__'):
in_origin = (in_origin, in_origin)
else:
if len(in_origin) != 2:
raise ValueError("'in_origin' must be a either a list "
" or a tuple with two elements (coordinates)")
if out_origin is not None:
if not hasattr(out_origin, '__iter__'):
out_origin = (out_origin, out_origin)
else:
if len(out_origin) != 2:
raise ValueError("'out_origin' must be a either a list "
" or a tuple with two elements (coordinates)")
# data type of the input mask:
int_inmask = np.issubdtype(inmask.dtype, np.bool_) or \
np.issubdtype(inmask.dtype, np.integer)
# data type of the output result:
if dtype is None:
if int_inmask:
odtype = inmask.dtype
else:
odtype = np.int8
else:
odtype = dtype
# auto determine output image size?
auto_out_shape = out_shape is None
###############################################
## To save time on drizzling, find out ##
## how much of the input mask needs to be ##
## drizzled and how big the output may be. ##
###############################################
#1. find the bounding box of the non-zero pixels in the input mask:
xmin, xmax, mbnx, ymin, ymax, mbny = _min_box(inmask, int_inmask, True)
# if there are no non-zero pixels return an empty array (if out_shape==None)
# or an array of zeros (if out_shape!=None):
if mbnx*mbny == 0:
if auto_out_shape:
if verbose:
print("WARNING: No non-zero data have been found in the input "
"mask.\nWARNING: Output mask will be empty.")
return (np.empty((mbny, mbnx), dtype=odtype), (None, None))
else:
return (np.zeros((mbny, mbnx), dtype=odtype), out_origin)
#2. Expand the bounding box by 'ceil(scale)' pixel:
pad = int(np.ceil(scale))
xmin = max(0, xmin-pad)
xmax = min(nx-1, xmax+pad)
ymin = max(0, ymin-pad)
ymax = min(ny-1, ymax+pad)
minview = np.s_[ymin:ymax+1,xmin:xmax+1]
#3. create smallest-sized numpy.float32 copy of input mask with
# element values 0 or 1:
in_mask_min = np.zeros((ymax-ymin+1, xmax-xmin+1), dtype=np.float32)
non_zeros = (inmask != 0)[minview]
in_mask_min[non_zeros] = 1.0
#4. find bounding box for output image:
# - compute the coordinates of the border
nintervals = np.ceil((xmax-xmin+1) / stepsize)
xr = np.linspace(xmin-0.5,xmax+0.5,nintervals,dtype=np.float)
nxr = xr.shape[0]
yr = np.linspace(ymin-0.5,ymax+0.5,nintervals,dtype=np.float)[1:-1]
nyr = yr.shape[0]
npts = 2 * (nxr+nyr)
in_borderx = np.empty((npts,), dtype=np.float)
in_bordery = np.empty((npts,), dtype=np.float)
in_borderx[0:nxr] = xr
in_bordery[0:nxr] = ymin-0.5
sl = np.s_[nxr:2*nxr]
in_borderx[sl] = xr
in_bordery[sl] = ymax+0.5
sl = np.s_[2*nxr:2*nxr+nyr]
in_borderx[sl] = xmin-0.5
in_bordery[sl] = yr
sl = np.s_[2*nxr+nyr:]
in_borderx[sl] = xmax+0.5
in_bordery[sl] = yr
in_borderx += in_origin[0]
in_bordery += in_origin[1]
# - convert these coordinates to the output frame:
out_borderx, out_bordery = coord_map(in_borderx, in_bordery)
oxmin = np.amin(out_borderx)
oxmax = np.amax(out_borderx)
oymin = np.amin(out_bordery)
oymax = np.amax(out_bordery)
onx = int(np.ceil(oxmax-oxmin+1))
ony = int(np.ceil(oymax-oymin+1))
#5. if the shape of the output mask was not provided, use the minimal
# bounding box for output mask to define output shape:
if out_shape is None:
out_shape = (ony-1, onx-1)
out_origin = (oxmin+0.5, oymin+0.5)
else:
if not _do_rect_intersect(
oxmin, oxmax, oymin, oymax,
out_origin[0]-0.5, out_origin[0]+out_shape[1]+0.5,
out_origin[1]-0.5, out_origin[1]+out_shape[0]+0.5
):
return (np.zeros(out_shape, dtype=odtype), out_origin)
#6. create pixel map:
# - create a list of pixel coordinates in the minimal mask:
in_y, in_x = np.indices(in_mask_min.shape, dtype=np.float)
in_x += xmin + in_origin[0]
in_y += ymin + in_origin[1]
# - compute pixel coordinates in the output (undistorted) frame:
out_x, out_y = coord_map(in_x, in_y)
# - create pixel map array:
pixmap = np.dstack((out_x, out_y))
#7. adjust pixmap coordinates to output origin:
pixmap -= np.asarray(out_origin, dtype=np.float)
##########################
## Drizzle the mask: ##
##########################
#1. create array for output drizzled mask and dummy arrays for output weight
# and context:
drizmask = np.zeros(out_shape, dtype=np.float32)
outwht = np.zeros(out_shape, dtype=np.float32)
outctx = np.zeros(out_shape, dtype=np.int32)
#2. create an array of weights if not provided:
if inwht is None:
in_wht_min = np.ones_like(in_mask_min)
else:
in_wht_min = inwht[minview]
#3. drizzle:
_vers, nmiss, nskip = cdrizzle.tdriz(
input=in_mask_min, weights=in_wht_min, pixmap=pixmap,
output=drizmask, counts=outwht, context=outctx,
uniqid=1, xmin=0, xmax=0,
ymin=0, ymax=0, scale=scale, pixfrac=pixfrac,
kernel=kernel, in_units='cps', expscale=1.0,
wtscale=1.0, fillstr=fillval)
#4. apply threshold to the output mask:
if comp == '>' or comp == 'gt':
valid_pix = np.greater(drizmask, compval)
elif comp == '>=' or comp == 'ge':
valid_pix = np.greater_equal(drizmask, compval)
elif comp == '<' or comp == 'lt':
valid_pix = np.less(drizmask, compval)
elif comp == '<=' or comp == 'le':
valid_pix = np.less_equal(drizmask, compval)
elif comp == '==' or comp == 'eq':
valid_pix = np.isclose(drizmask, compval)
elif comp == '!=' or comp == '<>' or comp == 'ne':
valid_pix = np.logical_not(np.isclose(drizmask, compval))
else:
raise ValueError("Unsupported comparison operator")
#5. create output mask while trimming it to minimal boundng box:
if auto_out_shape:
oxminf, oxmaxf, ombnx, oyminf, oymaxf, ombny = _min_box(
valid_pix.astype(dtype=np.int8),
True, False
)
if ombnx*ombny == 0:
if auto_out_shape:
if verbose:
print("WARNING: No non-zero data have been found in the "
"output drizzled mask.\nWARNING: "
"Output mask will be empty.")
return (np.empty((ombny, ombnx), dtype=odtype), (None,None))
else:
return (np.zeros((ombny, ombnx), dtype=odtype), out_shape)
outmask = np.zeros((oymaxf-oyminf+1, oxmaxf-oxminf+1), dtype=odtype)
outmask[valid_pix[oyminf:oymaxf+1, oxminf:oxmaxf+1]] = 1
else:
outmask = np.zeros_like(drizmask, dtype=odtype)
outmask[valid_pix] = 1
return (outmask, out_origin)