image.set - Function

Set pixel and/or mask values with a scalar in a region-of-interest of the image

Synopsis
set(pixels, pixelmask, region, list)

Arguments

pixels	in	The pixel value
		Allowed:	LEL scalar expression or numeric scalar
		Default:	unset
pixelmask	in	The pixel mask value
		Allowed:	T or F
		Default:	unset
region	in	The region of interest
		Allowed:	Region tool
		Default:	Whole image
list	in	List the bounding box and any mask creation to the logger
		Allowed:	T or F
		Default:	F

Returns
T or fail

Description

This function replaces data and/or mask values into the image in the specified region-of-interest. You can think of it as a simplified version of the image calculator.

Unlike the calc function, you can only set a scalar value for all pixels in the specified region-of-interest. For example, it can be useful to set a whole image to one value, or a mask in a region-of-interest to one value. Although you could do that with the related functions putregion and putchunk, you would have to make an array of the shape of the image and if that is large, it could be resource expensive.

The value for the pixels is specified with the pixels argument. It can be given as either a Lattice Expression Language (or LEL) expression string or a simple numeric scalar. See note 223 for a detailed description of the LEL expression syntax. If you give a LEL expression it must be a scalar expression.

Note that any default mask is ignored by this function when you set pixel values. This is different from calc where the extant mask is honoured.

The value for the pixel mask is specified with the pixelmask argument (T, F, unset). If it's unset then the mask is not changed.

If you specify pixelmask= T or F, then the mask that is affected is the current default mask (see maskhandler). If there is no mask, a mask is created for you and made the default mask.

Example

- im := imagefromshape('xx', [10,20])
- r1 := drm.box([2,2],[6,8])         # Make a box region
- im.set(pixels=1.0)                 # Set all pixels to 1
- im.set(pixels='1.0', region=r1)    # Set all pixels to 1 in the region
- im.set(pixels='min(yy)')           # Set all pixels to minimum of image yy
- im.set(pixels='min($im)', region=r1) # Set pixels in region to minimum of image xx
- im.set(pixelmask=T)                       # Set mask to all T
- im.set(pixels=0, pixelmask=F, region=r1)  #Set pixels and mask in region

Next: image.setbrightnessunit - Function Up: image - Tool Previous: image.sepconvolvegui - Function Contents Index

	Package	general
	Module	images
	Tool	image