1.1.1.0 image.putregion

NRAO Home > CASA > CASA Toolkit Reference Manual

image.putregion - Function

1.1.1 Put pixels and mask into a region-of-interest of the image

Description

This function replaces data and/or pixel mask values in the image in the specified region-of-interest. The pixels and/or pixelmask arrays must be the shape of the bounding box, and the whole bounding box is replaced in the image. The region-of-interest is really only used to specify the bounding box. If the region extends beyond the image, it is truncated. If the pixels or pixelmask array shapes do not match the bounding box, an error will result.

When you put a pixel mask, it either replaces the current default pixel mask, or is created. The pixel mask is put before the pixels.

The argument usemask is only relevant when you are putting pixel values and there is a pixel mask (meaning also the one you might have just put in place). If usemask=T then only pixels for which the mask is good (T) are altered. If usemask=F then all the pixels in the region are altered - the mask is ignored.

The argument replicate can be used to replicate the array throughout the image (from the blc to the trc). For example, if you provide a 2D array to a 3D image, you can replicate it through the third axis by setting replicate=T. The replication is done in the specified region.

The argument locking controls two things. If True, then after the function is called, the image is unlocked (so some other process can acquire a lock) and it is indicated that the image has changed. The reason for having this argument is that the unlocking and updating processes are quite expensive. If you are repeatedly calling putregion in a for loop, you would be advised to use this switch (and to consider using putchunk).

See the related functions putchunk, set and calc.

Arguments


Inputs
pixels	The pixel values. Default is none.
	allowed:	any
	Default:	variant
pixelmask	The pixel mask values. Default is none.
	allowed:	any
	Default:	variant
region	Region selection. See ”help par.region” for details. Default is to use the full image.
	allowed:	any
	Default:	any
list	List the bounding box and any mask creation to the logger
	allowed:	bool
	Default:	false
usemask	Honour the mask when putting pixels
	allowed:	bool
	Default:	true
locking	Unlock image after use?
	allowed:	bool
	Default:	true
replicate	Replicate array through image
	allowed:	bool
	Default:	false

Returns
bool

Example

Suppose that we have a 2-dimensional image.  First we recover the pixel
and \pixelmask\ values from a polygonal region.  Then we change the values in
the array that are within the region to zero and replace the data.

"""
#
print "\t----\t putregion Ex 1 \t----"
ia.maketestimage()                         # Attach an image to image tool
x = [’3pix’,’6pix’,’9pix’,’6pix’,’5pix’,’5pix’,’3pix’] # X vector abs pixels
y = [’3pix’,’4pix’,’7pix’,’9pix’,’7pix’,’5pix’,’3pix’] # Y vector abs pixels
mycs = ia.coordsys()
r1 = rg.wpolygon(x,y,csys=mycs.torecord()) # Create polygonal world region
mycs.done()
pixels = ia.getregion(r1)                  # Recover pixels
pixelmask = ia.getregion(r1, getmask=T)    # and mask
for i in range(len(pixels)):
  pixels[i] = list(pixels[i])              # convert tuple to list for mods
  for j in range(len(pixels[i])):
    if pixelmask[i][j]:
      pixels[i][j] = 0                     # Set pixels where mask is T to zero
  pixels[i] = tuple(pixels[i])             # convert list back to tuple
ia.putregion(pixels=pixels, pixelmask=pixelmask,
             region=r1)                    # Replace pixels only
ia.close()
#
"""

__________________________________________________________________

[next] [prev] [prev-tail] [front] [up]

More information about CASA may be found at the CASA web page

This code is available under the terms of the GNU General Public Lincense