lsst.ip.diffim g24bb6cda20+75fb473d53
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Classes | |
class | DcrModel |
Functions | |
applyDcr (image, dcr, useInverse=False, splitSubfilters=False, splitThreshold=0., doPrefilter=True, order=3) | |
calculateDcr (visitInfo, wcs, effectiveWavelength, bandwidth, dcrNumSubfilters, splitSubfilters=False) | |
calculateImageParallacticAngle (visitInfo, wcs) | |
wavelengthGenerator (effectiveWavelength, bandwidth, dcrNumSubfilters) | |
lsst.ip.diffim.dcrModel.applyDcr | ( | image, | |
dcr, | |||
useInverse = False, | |||
splitSubfilters = False, | |||
splitThreshold = 0., | |||
doPrefilter = True, | |||
order = 3 ) |
Shift an image along the X and Y directions. Parameters ---------- image : `numpy.ndarray` The input image to shift. dcr : `tuple` Shift calculated with ``calculateDcr``. Uses numpy axes ordering (Y, X). If ``splitSubfilters`` is set, each element is itself a `tuple` of two `float`, corresponding to the DCR shift at the two wavelengths. Otherwise, each element is a `float` corresponding to the DCR shift at the effective wavelength of the subfilter. useInverse : `bool`, optional Apply the shift in the opposite direction. Default: False splitSubfilters : `bool`, optional Calculate DCR for two evenly-spaced wavelengths in each subfilter, instead of at the midpoint. Default: False splitThreshold : `float`, optional Minimum DCR difference within a subfilter required to use ``splitSubfilters`` doPrefilter : `bool`, optional Spline filter the image before shifting, if set. Filtering is required, so only set to False if the image is already filtered. Filtering takes ~20% of the time of shifting, so if `applyDcr` will be called repeatedly on the same image it is more efficient to precalculate the filter. order : `int`, optional The order of the spline interpolation, default is 3. Returns ------- shiftedImage : `numpy.ndarray` A copy of the input image with the specified shift applied.
Definition at line 666 of file dcrModel.py.
lsst.ip.diffim.dcrModel.calculateDcr | ( | visitInfo, | |
wcs, | |||
effectiveWavelength, | |||
bandwidth, | |||
dcrNumSubfilters, | |||
splitSubfilters = False ) |
Calculate the shift in pixels of an exposure due to DCR. Parameters ---------- visitInfo : `lsst.afw.image.VisitInfo` Metadata for the exposure. wcs : `lsst.afw.geom.SkyWcs` Coordinate system definition (wcs) for the exposure. effectiveWavelength : `float` The effective wavelengths of the current filter, in nanometers. bandwidth : `float` The bandwidth of the current filter, in nanometers. dcrNumSubfilters : `int` Number of sub-filters used to model chromatic effects within a band. splitSubfilters : `bool`, optional Calculate DCR for two evenly-spaced wavelengths in each subfilter, instead of at the midpoint. Default: False Returns ------- dcrShift : `tuple` of two `float` The 2D shift due to DCR, in pixels. Uses numpy axes ordering (Y, X).
Definition at line 732 of file dcrModel.py.
lsst.ip.diffim.dcrModel.calculateImageParallacticAngle | ( | visitInfo, | |
wcs ) |
Calculate the total sky rotation angle of an exposure. Parameters ---------- visitInfo : `lsst.afw.image.VisitInfo` Metadata for the exposure. wcs : `lsst.afw.geom.SkyWcs` Coordinate system definition (wcs) for the exposure. Returns ------- `lsst.geom.Angle` The rotation of the image axis, East from North. Equal to the parallactic angle plus any additional rotation of the coordinate system. A rotation angle of 0 degrees is defined with North along the +y axis and East along the +x axis. A rotation angle of 90 degrees is defined with North along the +x axis and East along the -y axis.
Definition at line 788 of file dcrModel.py.
lsst.ip.diffim.dcrModel.wavelengthGenerator | ( | effectiveWavelength, | |
bandwidth, | |||
dcrNumSubfilters ) |
Iterate over the wavelength endpoints of subfilters. Parameters ---------- effectiveWavelength : `float` The effective wavelength of the current filter, in nanometers. bandwidth : `float` The bandwidth of the current filter, in nanometers. dcrNumSubfilters : `int` Number of sub-filters used to model chromatic effects within a band. Yields ------ `tuple` of two `float` The next set of wavelength endpoints for a subfilter, in nanometers.
Definition at line 820 of file dcrModel.py.