Package pydrizzle :: Class Pattern

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Class Pattern

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Set default values for these to be overridden by instrument specific class variables as necessary.

Instance Methods

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__init__(self, filename, output=None, pars=None)

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getHeaderHandle(self)
Sets up the PyFITS image handle and Primary header as self.image_handle and self.header.

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closeHandle(self)
Closes image_handle.

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addMembers(self, filename)
Build rootname for each SCI extension, and create the mask image from the DQ extension.

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applyAsnShifts(self)
Apply ASN Shifts to each member and the observations product.

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_applyShifts(self, in_wcs)
This method updates each member's WCS to reflect any offsets/corrections specified in the ASN table.

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getProductCorners(self)
Compute the product's corner positions based on input exposure's corner positions.

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buildProduct(self, filename, output)
Create Exposure object for meta-chip product after applying distortion model to input members.

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buildMetachip(self, update=yes)
Build up the new metashape based on the corrected size and position for each Exposure.

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transformMetachip(self, ref)
This method transforms this Exposure's WCS to be consistent with the provided reference WCS 'ref'.

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buildPars(self, ref=None)
This method would build a list of parameters to run 'drizzle' one a single input image.

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computeCubicCoeffs(self)
Method for converting cubic and Trauger coefficients tables into a usable form.

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computeOffsets(self, parity=None, refchip=None)
This version of 'computeOffsets' calculates the zero-point shifts to be included in the distortion coefficients table used by 'drizzle'.

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setNames(self, filename, output)
Define standard name attibutes:...

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getWCS(self)

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getMember(self, memname)
Return the class instance for the member with name memname.

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getMemberNames(self)
Return the names of all members for this Class.

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getExptime(self)

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DeltaXYtoOffset(self, delta)
Converts provided delta(x,y) pixel offset into a delta(RA,Dec) offset in arcseconds.

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Class Variables

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IDCKEY = 'IDCTAB'

PARITY = {'detector': DEFAULT_PARITY}

REFDATA = {'detector': [[1., 1.], [1., 1.]]}

NUM_IMSET = 3

PA_KEY = 'PA_V3'

DETECTOR_NAME = 'detector'

COPY_SUFFIX = '.orig'

Method Details

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getHeaderHandle(self)

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Sets up the PyFITS image handle and Primary header as self.image_handle and self.header.

When Pattern being used for output product, filename will be set to None and this returns None for header and image_handle.

addMembers(self, filename)

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Build rootname for each SCI extension, and create the mask image from the DQ extension. It would then append a new Exposure object to 'members' list for each extension.

_applyShifts(self, in_wcs)

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This method updates each member's WCS to reflect any offsets/corrections specified in the ASN table.

This method converts shifts given in output pixels into the input frame by using a reference image's WCS. This reference image must exist and have an header with a valid WCS; specifically, one which can be read using WCSObject.

buildMetachip(self, update=yes)

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Build up the new metashape based on the corrected size and position for each Exposure. (Pattern method)

transformMetachip(self, ref)

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This method transforms this Exposure's WCS to be consistent with the provided reference WCS 'ref'. This method only operates on the product MetaChip, with the original WCS being preserved as 'wcslin'.

Primarily, this transformation involves scaling and rotating the chip to match the reference frame values. Also, any specified size for the output frame would replace the default rotated/scaled size. All rotations would be about the center, and the reference pixel position gets shifted to accomodate this rotation.

buildPars(self, ref=None)

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This method would build a list of parameters to run 'drizzle'
one a single input image.
   The reference image info 'ref' will be passed as a SkyField object.
   The default output reference frame will be passed as 'def_wcs'
   for comparison to the user's selected object 'ref'.

computeCubicCoeffs(self)

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Method for converting cubic and Trauger coefficients tables into a usable form. It also replaces 'computeOffsets' for those tables as well.

computeOffsets(self, parity=None, refchip=None)

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This version of 'computeOffsets' calculates the zero-point shifts to be included in the distortion coefficients table used by 'drizzle'. It REQUIRES a parity matrix to convert from V2/V3 coordinates into detector image X/Y coordinates. This matrix will be specific to each detector.

setNames(self, filename, output)

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Define standard name attibutes:
        outname     - Default final output name
        outdata     - Name for drizzle science output
        outsingle   - Name for output for single image

getMemberNames(self)

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Return the names of all members for this Class. Output: [{self.name:[list of member names]}]