FlatGradient#

class lsst.ip.isr.FlatGradient(**kwargs)#

Bases: IsrCalib

Flat gradient measurements.

Parameters#

loglogging.Logger, optional

Log to write messages to. If None a default logger will be used.

**kwargs :

Additional parameters.

Methods Summary

computeFullModel(x, y, is_itl)

Compute the full gradient model given x/y and itl booleans.

computeGradientModel(x, y)

Compute the gradient model values.

computeRadialSplineModel(radius)

Compute the radial spline model values from radii.

computeRadialSplineModelXY(x, y)

Compute the radial spline model values from x/y.

fromDict(dictionary)

Construct a FlatGradient from a dictionary of properties.

fromTable(tableList)

Construct a calibration from a list of tables.

setParameters(*, radialSplineNodes, ...[, ...])

Set the parameters for the gradient model.

toDict()

Return a dictionary containing the calibration properties.

toTable()

Construct a list of table(s) containing the FlatGradient data.

Methods Documentation

computeFullModel(x, y, is_itl)#

Compute the full gradient model given x/y and itl booleans.

This returns the full model that can be applied directly to data that was used in a fit.

Parameters#

xnp.ndarray

Array of focal plane x values (mm).

ynp.ndarray

Array of focal plane y values (mm).

is_itlnp.ndarray

Boolean array of whether each point is from an ITL detector.

Returns#

modelnp.ndarray

Model values at each position.

computeGradientModel(x, y)#

Compute the gradient model values.

The gradient model is a plane constrained to be 1.0 at the centroidX, centroidY values. Dividing by this model will remove the planar gradient in a flat field. Note that the planar gradient pivot is always at the same position, and does not move with the radial gradient centroid so as to keep the model fit more stable.

Parameters#

xnp.ndarray

Array of focal plane x values (mm).

ynp.ndarray

Array of focal plane y values (mm).

Returns#

gradientModelnp.ndarray

Gradient model values at the x/y positions.

computeRadialSplineModel(radius)#

Compute the radial spline model values from radii.

The spline model is a 1D Akima spline. When computed, the values from the model describe the radial function of the full focal plane flat-field. Dividing by this model will yield a radially flattened flat-field.

Parameters#

radiusnp.ndarray

Array of focal plane radii (mm).

Returns#

splineModelnp.ndarray

Spline model values at the radius positions.

computeRadialSplineModelXY(x, y)#

Compute the radial spline model values from x/y.

The spline model is a 1D Akima spline. When computed, the values from the model describe the radial function of the full focal plane flat-field. Dividing by this model will yield a radially flattened flat-field.

Parameters#

xnp.ndarray

Array of focal plane x values (mm).

ynp.ndarray

Array of focal plane y values (mm).

Returns#

splineModelnp.ndarray

Spline model values at the x/y positions.

classmethod fromDict(dictionary)#

Construct a FlatGradient from a dictionary of properties.

Parameters#

dictionarydict

Dictionary of properties.

Returns#

caliblsst.ip.isr.FlatGradient

Constructed calibration.

classmethod fromTable(tableList)#

Construct a calibration from a list of tables.

Parameters#

tableListlist [astropy.table.Table]

List of table(s) to use to construct the FlatGradient.

Returns#

caliblsst.ip.isr.FlatGradient

The calibration defined in the table(s).

setParameters(*, radialSplineNodes, radialSplineValues, itlRatio=1.0, centroidX=0.0, centroidY=0.0, centroidDeltaX=0.0, centroidDeltaY=0.0, gradientX=0.0, gradientY=0.0, normalizationFactor=1.0)#

Set the parameters for the gradient model.

Parameters#

radialSplineNodesnp.ndarray

Array of spline nodes.

radialSplineValuesnp.ndarray

Array of spline values (same length as radialSplineNodes).

itlRatiofloat, optional

Ratio of flat for ITL detectors to E2V detectors.

centroidXfloat, optional

X centroid of the focal plane (mm). This will be used as the pivot for the gradient plane.

centroidYfloat, optional

Y centroid of the focal plane (mm). This will be used as the pivot for the gradient plane.

centroidDeltaXfloat, optional

Centroid offset (mm). This is used in the radial function to allow for mis-centering in the illumination gradient.

centroidDeltaYfloat, optional

Centroid offset (mm). This is used in the radial function to allow for mis-centering in the illumination gradient.

gradientXfloat, optional

Slope of gradient in x direction (throughput/mm).

gradientYfloat, optional

Slope of gradient in y direction (throughput/mm).

normalizationFactorfloat, optional

Overall normalization factor (used to, e.g. make the center of the focal plane equal to 1.0 vs. a focal-plane average.

toDict()#

Return a dictionary containing the calibration properties.

Returns#

dictionarydict

Dictionary of properties.

toTable()#

Construct a list of table(s) containing the FlatGradient data.

Returns#

tableListlist [astropy.table.Table]

List of tables containing the FlatGradient information.