lsst.pipe.tasks.scaleZeroPoint.ScaleZeroPointTask Class Reference

Inheritance diagram for lsst.pipe.tasks.scaleZeroPoint.ScaleZeroPointTask:

Public Member Functions
def	__init__ (self, *args, **kwargs)
def	run (self, exposure, dataRef=None)
def	computeImageScaler (self, exposure, dataRef=None)
def	getPhotoCalib (self)
def	scaleFromPhotoCalib (self, calib)
def	scaleFromFluxMag0 (self, fluxMag0)

Static Public Attributes
	ConfigClass = ScaleZeroPointConfig

Detailed Description

Compute scale factor to scale exposures to a desired photometric zero point

This simple version assumes that the zero point is spatially invariant.

Definition at line 132 of file scaleZeroPoint.py.

Constructor & Destructor Documentation

__init__()

def lsst.pipe.tasks.scaleZeroPoint.ScaleZeroPointTask.__init__	(		self,
		*	args,
		**	kwargs
	)

Construct a ScaleZeroPointTask

Reimplemented in lsst.pipe.tasks.scaleZeroPoint.SpatialScaleZeroPointTask.

Definition at line 140 of file scaleZeroPoint.py.

    def __init__(self, *args, **kwargs):
        """Construct a ScaleZeroPointTask
        """
        pipeBase.Task.__init__(self, *args, **kwargs)
 
        # flux at mag=0 is 10^(zeroPoint/2.5)   because m = -2.5*log10(F/F0)
        fluxMag0 = 10**(0.4 * self.config.zeroPoint)
        self._photoCalib = afwImage.makePhotoCalibFromCalibZeroPoint(fluxMag0, 0.0)
 

Member Function Documentation

computeImageScaler()

def lsst.pipe.tasks.scaleZeroPoint.ScaleZeroPointTask.computeImageScaler	(		self,
			exposure,
			dataRef = None
	)

Compute image scaling object for a given exposure.

@param[in] exposure: exposure for which scaling is desired
@param[in] dataRef: dataRef for exposure.
                       Not used, but in API so that users can switch between spatially variant
                       and invariant tasks

Reimplemented in lsst.pipe.tasks.scaleZeroPoint.SpatialScaleZeroPointTask.

Definition at line 166 of file scaleZeroPoint.py.

    def computeImageScaler(self, exposure, dataRef=None):
        """Compute image scaling object for a given exposure.
 
        @param[in] exposure: exposure for which scaling is desired
        @param[in] dataRef: dataRef for exposure.
                               Not used, but in API so that users can switch between spatially variant
                               and invariant tasks
        """
        scale = self.scaleFromPhotoCalib(exposure.getPhotoCalib()).scale
        return ImageScaler(scale)
 

getPhotoCalib()

def lsst.pipe.tasks.scaleZeroPoint.ScaleZeroPointTask.getPhotoCalib

(

self

)

Get desired PhotoCalib

@return calibration (lsst.afw.image.PhotoCalib) with fluxMag0 set appropriately for config.zeroPoint

Definition at line 177 of file scaleZeroPoint.py.

    def getPhotoCalib(self):
        """Get desired PhotoCalib
 
        @return calibration (lsst.afw.image.PhotoCalib) with fluxMag0 set appropriately for config.zeroPoint
        """
        return self._photoCalib
 

run()

def lsst.pipe.tasks.scaleZeroPoint.ScaleZeroPointTask.run	(		self,
			exposure,
			dataRef = None
	)

Scale the specified exposure to the desired photometric zeropoint

@param[in,out] exposure: exposure to scale; masked image is scaled in place
@param[in] dataRef: dataRef for exposure.
                       Not used, but in API so that users can switch between spatially variant
                       and invariant tasks
@return a pipeBase.Struct containing:
- imageScaler: the image scaling object used to scale exposure

Reimplemented in lsst.pipe.tasks.scaleZeroPoint.SpatialScaleZeroPointTask.

Definition at line 149 of file scaleZeroPoint.py.

    def run(self, exposure, dataRef=None):
        """Scale the specified exposure to the desired photometric zeropoint
 
        @param[in,out] exposure: exposure to scale; masked image is scaled in place
        @param[in] dataRef: dataRef for exposure.
                               Not used, but in API so that users can switch between spatially variant
                               and invariant tasks
        @return a pipeBase.Struct containing:
        - imageScaler: the image scaling object used to scale exposure
        """
        imageScaler = self.computeImageScaler(exposure=exposure, dataRef=dataRef)
        mi = exposure.getMaskedImage()
        imageScaler.scaleMaskedImage(mi)
        return pipeBase.Struct(
            imageScaler=imageScaler,
        )
 

scaleFromFluxMag0()

def lsst.pipe.tasks.scaleZeroPoint.ScaleZeroPointTask.scaleFromFluxMag0	(		self,
			fluxMag0
	)

Compute the scale for the specified fluxMag0

This is a wrapper around scaleFromPhotoCalib, which see for more information

@param[in] fluxMag0
@return a pipeBase.Struct containing:
- scale, as described in scaleFromPhotoCalib.

Definition at line 202 of file scaleZeroPoint.py.

    def scaleFromFluxMag0(self, fluxMag0):
        """Compute the scale for the specified fluxMag0
 
        This is a wrapper around scaleFromPhotoCalib, which see for more information
 
        @param[in] fluxMag0
        @return a pipeBase.Struct containing:
        - scale, as described in scaleFromPhotoCalib.
        """
        calib = afwImage.makePhotoCalibFromCalibZeroPoint(fluxMag0, 0.0)
        return self.scaleFromPhotoCalib(calib)
 
 

scaleFromPhotoCalib()

def lsst.pipe.tasks.scaleZeroPoint.ScaleZeroPointTask.scaleFromPhotoCalib	(		self,
			calib
	)

Compute the scale for the specified PhotoCalib

Compute scale, such that if pixelCalib describes the photometric zeropoint of a pixel
then the following scales that pixel to the photometric zeropoint specified by config.zeroPoint:
    scale = computeScale(pixelCalib)
    pixel *= scale

@return a pipeBase.Struct containing:
- scale, as described above.

@note: returns a struct to leave room for scaleErr in a future implementation.

Definition at line 184 of file scaleZeroPoint.py.

    def scaleFromPhotoCalib(self, calib):
        """Compute the scale for the specified PhotoCalib
 
        Compute scale, such that if pixelCalib describes the photometric zeropoint of a pixel
        then the following scales that pixel to the photometric zeropoint specified by config.zeroPoint:
            scale = computeScale(pixelCalib)
            pixel *= scale
 
        @return a pipeBase.Struct containing:
        - scale, as described above.
 
        @note: returns a struct to leave room for scaleErr in a future implementation.
        """
        fluxAtZeroPoint = calib.magnitudeToInstFlux(self.config.zeroPoint)
        return pipeBase.Struct(
            scale=1.0 / fluxAtZeroPoint,
        )
 

Member Data Documentation

ConfigClass

lsst.pipe.tasks.scaleZeroPoint.ScaleZeroPointTask.ConfigClass = ScaleZeroPointConfig

static

Definition at line 137 of file scaleZeroPoint.py.

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The documentation for this class was generated from the following file:

• /j/snowflake/release/lsstsw/stack/lsst-scipipe-0.7.0/Linux64/pipe_tasks/21.0.0-172-gfb10e10a+18fedfabac/python/lsst/pipe/tasks/scaleZeroPoint.py