hermes.pipeline.components.remove2dflatfield.remove2dFlatField Class Reference

Removes 2D flat field from images. More...

Inheritance diagram for hermes.pipeline.components.remove2dflatfield.remove2dFlatField:

Public Member Functions
def	__init__
	Make a Hermes component and initialize variables.
def	optionsAreValid
	Check user's options.
def	__call__
	Eliminate fringes in 2D where possible (at least in the core of spectral orders)
Public Member Functions inherited from hermes.pipeline.core.pipelinecomponent.PipelineComponent
def	__init__
def	__call__
def	optionsAreValid
def	getOptions
def	setOptions
def	checkExistShapeUnits
def	isOption

Public Attributes
	isDebug
	If isDebug is set to True, intermediate debug files are produced in the "debug" folder. More...
	results
Public Attributes inherited from hermes.pipeline.core.pipelinecomponent.PipelineComponent
	options
	logger
	ConsoleLogSeverity
	default value
	canShowGraphics
	when machine does not run matplotlib. More...

Detailed Description

Removes 2D flat field from images.

PURPOSE :

This module uses a pre-defined instrument model fringe frame
(a normalised two-dimensional flat-field frame) to correct for
pixel-to-pixel sensitivity variatons and fringe patterns. Such frame
can be constructed with the required precision (random noise at least
a factor 3 lower than the random noise present in the science frame)
only in pixels with high intensity. Hence, it consists of values
exactly equal to 1.0 in pixels where this condition is not fulfilled.
The contribution of the random noise in the fringe frame to the
2D-flat-fielded input frame is taken into account.


COMMENTS :

Since a pre-defined frame is used, we assume implicitly a high level of
wavelength stability (fringes depend critically on wavelength). Any
significant shift in wavelengths on the detector will require the
construction of a new instrument model fringe frame. We assume also that
small shifts of spectral orders in the cross-order position do not affect
the fringe pattern.

In principle, a 'wider' fringe frame (covering effectively more pixels) may be
constructed by combination of flat-field frames with forced shifts of the
spectral orders in cross-order position, such that more/all pixels receive
a high intensity in at least some flat-field frames.


SYNTAX :

self.results = Remove2dFlatField(self.results)



INPUT CONSTANTS FROM INSTRUMENT MODEL :

Image with the 2D-fringes for the observing mode of the input image, from
the instrument model




INPUT DATA FROM RESULTDICT :

Image with shape of detector and electron units.




OPTIONS READ FROM OPTIONDICT :

MANDATORY :

OPTIONAL :
    isDebug (Boolean : True or False)
        default value : False
        writes two fits files with the results
            image           in 'T20image.fits')
            imageVariance   in 'T21imageVariance.fits')


OUTPUT :

2D flat-fielded image saved in self.results["image"], and the corresponding
variance frame, saved in self.results["varimage"]

Member Data Documentation

hermes.pipeline.components.remove2dflatfield.remove2dFlatField.isDebug

If isDebug is set to True, intermediate debug files are produced in the "debug" folder.

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

• pipeline/components/remove2dflatfield.py