hermes.pipeline.components.modelorderpositions.modelOrderPositions Class Reference

Construct a differential (or absolute) model for the positions of the spectral orders. More...

Inheritance diagram for hermes.pipeline.components.modelorderpositions.modelOrderPositions:

Public Member Functions
def	__init__
	Make a Hermes component and initialize variables.
def	optionsAreValid
	Read User's options.
def	__call__
	The run is launched here.
def	getModelAbsoluteAndRelativeOrderPositions
	computes and returns the absolute and relative orderpositions of the frame. More...
def	isBetterSolutionNeeded
	checks if we need to search for a better model by excluding outliers. More...
def	getBivariatePolynomialValue
	computes and returns the result of the bivariate polynomial (our model) for a given order and row/column index. More...
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
	orderMid
	default value. More...
	rowMid
	same
	maxAllowedIterations
	maxAllowedIterations is an integer, default is 1
	areVirtualEdgeOrdersAdded
	areVirtualEdgeOrdersAdded : Boolean, defaults is True
	polyorder
	PolynomeDegreeInOrderDirection is integer, defaults is 3.
	polyrow
	PolynomeDegreeInRowDirection is an integer, defaults is 3.
	tolerance
	tolerance is a float, defaults is 4.5
	isDifferential
	isDifferential is a Boolean, defaults is True
	isDebug
	isDebug is False by default. More...
	areRelativeCoordinates
	areRelativeCoordinates is a boolean, default is True
	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

Construct a differential (or absolute) model for the positions of the spectral orders.

PURPOSE :

    This module contains several types of two-dimensional model functions
    that may represent the positions of the spectral orders on the detector.
    At present, only the bivariate-polynomial model is included. It accepts
    input data weighted that passed the credibility test set-up in
    measureOrderPosition. Data obtained during commissioning time, or a
    dedicated study by an instrument maintainer can result in a more robust
    model (less parameters involved to obtain the same or better precision).

    The accuracy of the model and trends of the deviations (in terms of a
    number of parameters) can be evaluated. Standard evaluation includes: \n
    - rms of the residuals 'observed - computed' position ("O - C") in bins
    of correlation coefficients; \n
    - non-parametric statistics on the number of changes of sign in subsequent
    "O - C" along spectral order; \n
    - correlation between "O - C" and the discretisation of the cross-order
    profile i.e. the sub-pixel position of the centre of the spectral order
    in the considered cross-cut



COMMENTS :

    Two-dimensional models are more robust than a sequence of one-dimensional
    models (each one for a specific spectral order) and have the advantage that
    low-quality input data can be masked or appropriately weighted, even in the
    case that they cover a significant part of a given order. Data not used in
    the merged final spectra, for reasons of optical quality or vignetting,
    should never be included.






INPUT CONSTANTS FROM INSTRUMENT MODEL :

MANDATORY :




INPUT DATA FROM RESULTDICT :

MANDATORY :
    differentialOrderPosition
        array with the measured change in order position

    MeasuredOrderPositions  # not seen in tex #
        Is a masked array with the relative/absolute order positions template.

    ccCoefficientsMeasureOrderPosition
        array with the cross-correlation coefficients obtained at all shifts




OPTIONS READ FROM OPTIONDICT :

MANDATORY :

    PolynomeDegreeInOrderDirection (int)
        default is 3
        It corresponds to the degree of the bivariate polynomial in the cross order direction.
        (i.e. the degree is therefore 7 per default)
    PolynomeDegreeInRowDirection (in)
        default is 3
        It corresponds to the degree of the bivariate polynomial in the cross row direction.
        (i.e. the degree is therefore 5 per default)
    areRelativeCoordinates (boolean)
        default is True
        De we used relative CCD coordinates to model the order positions

OPTIONAL :

    areVirtualEdgeOrdersAdded (boolean)
        hardcoded value is True
        to measure the background we need one additional order on both sides of the CCD

    maxAllowedIterations
        maximum number of iterations allowed to remove accidental outliers.
        default = 3

    isDebug (boolean)
        default is True
        debug information is written when this parameter is True.
        When true, you will find in the self.results["DebugPath"], the following
        fits files:
            mAbsOPos.fits



OUTPUT written in the RESULTDICT :

modelOrderPositionCoefficients
    Are the coefficients of the bivariate polynomial.
modelAbsoluteOrderPositions
    Is a MxN frame, where M is the row/column index and N is the order-1 number, that
    contains the column/row index of the order center of the image.

Member Function Documentation

def hermes.pipeline.components.modelorderpositions.modelOrderPositions.getBivariatePolynomialValue	(		self,
			iorder,
			index,
			coefs
	)

computes and returns the result of the bivariate polynomial (our model) for a given order and row/column index.

Coefficients must be provided.

def hermes.pipeline.components.modelorderpositions.modelOrderPositions.getModelAbsoluteAndRelativeOrderPositions

(

self

)

computes and returns the absolute and relative orderpositions of the frame.

def hermes.pipeline.components.modelorderpositions.modelOrderPositions.isBetterSolutionNeeded	(		self,
			relativePositions,
			modelRelativePositions
	)

checks if we need to search for a better model by excluding outliers.

It returns a boolean and the relativePositions with an updated mask.

Member Data Documentation

hermes.pipeline.components.modelorderpositions.modelOrderPositions.isDebug

isDebug is False by default.

When set to True, intermediate files are written in the debug folder. This is meant to let the user find out why his results are not the expected ones. Usually it reflects a change in the instrument that has to be fixed.

hermes.pipeline.components.modelorderpositions.modelOrderPositions.orderMid

default value.

Means that we do not express the order and row/column index relatively to the middle of the CCD

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

• pipeline/components/modelorderpositions.py