2.3.1.0 imager.boxmask

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imager.boxmask - Function

2.3.1 Construct a mask image from blc, trc

Description

A mask image is an image with the same shape as the other images but with values between 0.0 and 1.0 as a pixel value. Mask images are used in imager to control the region selected in a deconvolution.

In the Clark CLEAN, the mask image can usefully have any value between 0.0 and 1.0. Intermediate value discourage but do not rule out selection of clean components in that region. This is accomplished by multiplying the residual image by the mask prior to entering the minor cycle. Note that if you do use a mask for the Clark or Hogbom Clean, it must cover only a quarter of the image. boxmask does not enforce this requirement.

Arguments


Inputs
mask	name of mask image
	allowed:	string
	Default:
blc	Bottom left corner
	allowed:	intArray
	Default:	0 0 0 0
trc	Top right corner, should be image shape
	allowed:	intArray
	Default:
value	Value to fill in
	allowed:	double
	Default:	1.0

Returns
bool

Example

im.boxmask(mask=’bigmask’, blc=[56,45,1,1], trc=[87,93,4,1])
im.clean(mask=’bigmask’, model=’3C273XC1.clean.masked’, niter=1000)

Makes the image bigmask, and then sets it to unity for all points in
the region bounded by the blc and trc. Then cleans using it as the
mask.

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