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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()  
#  
"""  
 

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