Inheritance diagram for lsst.display.matplotlib.matplotlib.AsinhNormalize:

Public Member Functions
	__init__ (self, minimum=0, dataRange=1, Q=8)

Public Attributes
	mapping

Protected Member Functions
	_getMinMaxQ (self)

Detailed Description

Provide an asinh stretch for mtv()

Definition at line 783 of file matplotlib.py.

Constructor & Destructor Documentation

◆ init()

lsst.display.matplotlib.matplotlib.AsinhNormalize.__init__	(	self,
		minimum = 0,
		dataRange = 1,
		Q = 8 )

Initialise an object able to carry out an asinh mapping

@param minimum   Minimum pixel value (default: 0)
@param dataRange Range of values for stretch if Q=0; roughly the
                 linear part (default: 1)
@param Q Softening parameter (default: 8)

See Lupton et al., PASP 116, 133

Reimplemented in lsst.display.matplotlib.matplotlib.AsinhZScaleNormalize.

Definition at line 785 of file matplotlib.py.

    def __init__(self, minimum=0, dataRange=1, Q=8):
        """Initialise an object able to carry out an asinh mapping
 
        @param minimum   Minimum pixel value (default: 0)
        @param dataRange Range of values for stretch if Q=0; roughly the
                         linear part (default: 1)
        @param Q Softening parameter (default: 8)
 
        See Lupton et al., PASP 116, 133
        """
        # The object used to perform the desired mapping
        self.mapping = afwRgb.AsinhMapping(minimum, dataRange, Q)
 
        vmin, vmax = self._getMinMaxQ()[0:2]
        if vmax*Q > vmin:
            vmax *= Q
        super().__init__(vmin, vmax)
 

Member Function Documentation

◆ _getMinMaxQ()

lsst.display.matplotlib.matplotlib.AsinhNormalize._getMinMaxQ ( self )

protected

Return an asinh mapping's minimum and maximum value, and Q

Regrettably this information is not preserved by AsinhMapping
so we have to reverse engineer it

Definition at line 803 of file matplotlib.py.

    def _getMinMaxQ(self):
        """Return an asinh mapping's minimum and maximum value, and Q
 
        Regrettably this information is not preserved by AsinhMapping
        so we have to reverse engineer it
        """
 
        frac = 0.1                      # magic number in AsinhMapping
        Q = np.sinh((frac*self.mapping._uint8Max)/self.mapping._slope)/frac
        dataRange = Q/self.mapping._soften
 
        vmin = self.mapping.minimum[0]
        return vmin, vmin + dataRange, Q
 
 

Member Data Documentation

◆ mapping

lsst.display.matplotlib.matplotlib.AsinhNormalize.mapping

Definition at line 796 of file matplotlib.py.

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

/j/snowflake/release/lsstsw/stack/lsst-scipipe-9.0.0/Linux64/display_matplotlib/g3a166c0a6a+a99b0ab4cd/python/lsst/display/matplotlib/matplotlib.py

Public Member Functions

Public Attributes

Protected Member Functions