[ Basic Info | User Guide ]

# Basic Information on avmaths

```
Purpose: Operate on cube with averaged plane from cube
Categories: analysis

AVMATHS averages designated planes from a cube, and then
performs some mathematical operation on the cube with the
averaged plane.  Subtraction, optical depth, replacement,
and multiplication operations have been coded.  Undefined
output pixels are blanked.

Key: in
The input image. Wild card expansion is supported. No default.

Key: out
The output image. No default.

Key: region
Specify the channels to average with a REGION=IMAGE
command such as
region=image(1,5),image(120,128)
This would average channels 1:5 and 120:128 from the
cube.  No other region commands are accepted for example
spatial sub-regions will be ignored.

Key: options
Task enrichment options.  Minimum match is active.

"subtract"  OUT(i,j,k) = IN(i,j,k) - AV(i,j)
"odepth"    OUT(i,j,k) = ln(AV(i,j) / IN(i,j,k))
"replace"   OUT(i,j)   = AV(i,j)
"multiply"  OUT(i,j,k) = IN(i,j,k) * AV(i,j)

"noreduce" causes the output image to be of the same dimensions
as the input image when REPLACEMENT is invoked.  By default,
the REPLACED output image is reduced to two dimensions as
there is probably no point to replicating one plane N times.
In this case, the output third axis descriptors reflect the
size of the bounding box of the selected region on the third
axis

Pixels are blanked if the input pixel is blanked, the averaged
channel pixel is blanked, or the output is undefined.

Revision: 1.7, 2013/08/30 01:49:21 UTC
```

Generated by miriad@atnf.csiro.au on 21 Jun 2016