1.1.1.0 image.pbcor

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image.pbcor - Function

1.1.1 Construct a primary beam corrected image from an image and a primary beam

Description

Correct an image for primary beam attenuation using an image of the primary beam pattern. The primary beam pattern can be provided as an image, in which case 1. it must have the same shape as the input image and its coordinate system must be the same, or 2. it must be a 2-D image in which case its coordinate system must consist of a (2-D) direction coordinate which is the same as the direction coordinate in the input image and its direction plane must be the same shape as that of the input image. Alternatively, pbimage can be an array of pixel values in which case the same dimensionality and shape constraints apply. An image tool referencing the corrected image is returned. The corrected image will also be written to disk if outfile is not empty (and overwrite=True if outfile already exists). One can choose between dividing the image by the primary beam pattern (mode=”divide”) or multiplying the image by the primary beam pattern (mode=”multiply”). One can also choose to specify a cutoff limit for the primary beam pattern. For mode=”divide”, for all pixels below this cutoff in the primary beam pattern, the output image will be masked. In the case of mode=”multiply”, all pixels in the output will be masked corresponding to pixels with values greater than the cutoff in the primary beam pattern. A negative value for cutoff means that no cutoff will be applied, which is the default.

Arguments


Inputs
pbimage	Name of the primary beam image which must exist or array of values for the pb response. Default ””
	allowed:	any
	Default:	variant
outfile	Output image name. If empty, no image is written. Default ””
	allowed:	string
	Default:
overwrite	Overwrite the output if it exists? Default False
	allowed:	bool
	Default:	false
box	Rectangular region(s) to select in direction plane. Default is to use the entire direction plane.
	allowed:	string
	Default:
region	Region selection. Default is to use the full image.
	allowed:	any
	Default:	variant
chans	Channels to use. Default is to use all channels.
	allowed:	string
	Default:
stokes	Stokes planes to use. Default is to use all stokes planes.
	allowed:	string
	Default:
mask	Mask to use. Default is none.
	allowed:	string
	Default:	variant
mode	Divide or multiply the image by the primary beam image. Minimal match supported. Default ”divide”
	allowed:	string
	Default:	divide
cutoff	PB cutoff. If mode is ”d”, all values less than this will be masked. If ”m”, all values greater will be masked. Less than 0, no cutoff. Default no cutoff
	allowed:	float
	Default:	-1.0
stretch	Stretch the mask if necessary and possible? Default False
	allowed:	bool
	Default:	false

Returns
image

Example

        ia.open("attenuated.im")
        pbia = ia.pbcor(pbimage="mypb.im", outname="pbcorred.im", mode="divide", cutoff=0.1)
        ia.done()
        # do stuff with ia tool attached to pb image and close it
        pbia.done()

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