lsst.afw.display.rgb._rgbContinued.AsinhZScaleMapping Class Reference

Inheritance diagram for lsst.afw.display.rgb._rgbContinued.AsinhZScaleMapping:

Public Member Functions
	__init__ (self, image, Q=8, pedestal=None)

Protected Attributes
	_image

Detailed Description

A mapping for an asinh stretch, estimating the linear stretch by zscale

x = asinh(Q (I - z1)/(z2 - z1))/Q

Parameters
----------
image
    The image to analyse, or a list of 3 images to be converted to an intensity image
Q : `int`
    The asinh softening parameter
pedestal : `float` or sequence of `float`, optional
    The value, or array of 3 values, to subtract from the images

    N.b. pedestal, if not None, is removed from the images when calculating the zscale
    stretch, and added back into Mapping.minimum[]

See also
--------
AsinhMapping

Definition at line 324 of file _rgbContinued.py.

Constructor & Destructor Documentation

__init__()

lsst.afw.display.rgb._rgbContinued.AsinhZScaleMapping.__init__	(		self,
			image,
			Q = 8,
			pedestal = None )

Reimplemented from lsst.afw.display.rgb._rgbContinued.AsinhMapping.

Definition at line 346 of file _rgbContinued.py.

    def __init__(self, image, Q=8, pedestal=None):
        try:
            assert len(image) in (1, 3,), "Please provide 1 or 3 images"
        except TypeError:
            image = [image]
 
        if pedestal is not None:
            try:
                assert len(pedestal) in (
                    1, 3,), "Please provide 1 or 3 pedestals"
            except TypeError:
                pedestal = 3*[pedestal]
 
            image = list(image)        # needs to be mutable
            for i, im in enumerate(image):
                if pedestal[i] != 0.0:
                    if hasattr(im, "getImage"):
                        im = im.getImage()
                    if hasattr(im, "getArray"):
                        im = im.getArray()
 
                    image[i] = im - pedestal[i]  # n.b. a copy
        else:
            pedestal = len(image)*[0.0]
 
        image = computeIntensity(*image)
 
        zscale = ZScaleMapping(image)
        # zscale.minimum is always a triple
        dataRange = zscale.maximum - zscale.minimum[0]
        minimum = zscale.minimum
 
        for i, level in enumerate(pedestal):
            minimum[i] += level
 
        AsinhMapping.__init__(self, minimum, dataRange, Q)
        self._image = image             # support self.makeRgbImage()
 
 

Member Data Documentation

_image

lsst.afw.display.rgb._rgbContinued.AsinhZScaleMapping._image

protected

Definition at line 382 of file _rgbContinued.py.

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

• /j/snowflake/release/lsstsw/stack/lsst-scipipe-8.0.0/Linux64/afw/g5a732f18d5+be83d3ecdb/python/lsst/afw/display/rgb/_rgbContinued.py