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.help mkimage Oct87 noao.imred.ccdred.ccdtest
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NAME
mkimage -- Make or modify and image with simple values
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USAGE
mkimage image option value [ndim dims]
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PARAMETERS
.ls image
Image to create or modify.
.le
.ls option
Editing option which is one of the following:
.ls make
Make a new image of the specified size, dimensionality, pixel type, and values.
.le
.ls replace
Replace pixel values in the image.
.le
.ls add
Add to the pixel values in the image.
.le
.ls multiply
Multiply the pixel values in the image.
.le
.le
.ls value
Mean pixel value to be used.
.le
.ls ndim
Number of dimensions when creating a new image.
.le
.ls dims
Image dimensions given as a white space separated string (see the examples).
.le
.ls pixtype = "real"
Pixel datatype when creating an image. The types are "real", "short",
"integer", "long", and "double".
.le
.ls slope = 0.
Slope of pixel values per pixel.
.le
.ls sigma = 0.
Gaussian noise of pixel values if not zero.
.le
.ls seed = 0
Seed for random numbers. If zero then the first time the task is
called a seed of 1 is used and all subsequent calls while the task is in
the process cache continue with new random numbers.
.le
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DESCRIPTION
An image is created or modified using simple values. This task is intended
for test and demonstration purposes. A image may be created of a specified
size, dimensionality, and pixel datatype. The pixel values used in creating
or editing an image consist of a sloped plane (which repeats for dimensions
greater than 2) with pseudo-Gaussian noise. The sloped plane is defined such
that:
pix[i,j] = value + slope * ((ncols + nlines) / 2 - 1) + slope * (i + j)
where i and j are the pixel indices (starting with 1) and ncols and nlines
are the number of columns and lines. The interpretation of "value" is that
it is the mean of the plane. The Gaussian noise is only approximately random
for purposes of speed!
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EXAMPLES
1. To create an 2 dimensional real image of size 100 x 200 with all zero
values:
cl> mkimage name make 0 2 "100 200"
Note that the dimension string is quoted because of the blank separated
values.
2. To add noise with a sigma of 5:
cl> mkimage name add 0 sigma=5
2. To replace a region of the image with the value 10:
cl> mkimage name[10:20,30:40] replace 10
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SEE ALSO
artobs, subsection
.endhelp
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