.help minmax May91 images.imutil
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NAME
minmax -- compute the minimum and maximum pixel values of an image
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USAGE
minmax images
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PARAMETERS
.ls images
Image template specifying the images to be examined.
.le
.ls force = no
Force recomputation of the minimum and maximum pixel and pixel values even if
they are noted as up to date in the image header.
.le
.ls update = yes
Update the image header with the new values (requires write permission).
.le
.ls verbose = yes
Print the image name, minimum value, and maximum value of each image
processed.
.le
.ls minval = INDEF
Set to the minimum pixel value of the last image processed.
If the pixel type of the last input image was complex, this is the real
part of the minimum value.
.le
.ls maxval = INDEF
Set to the maximum pixel value of the last image processed.
If the pixel type of the last input image was complex, this is the real
part of the maximum value.
.le
.ls iminval = INDEF
Set to the minimum imaginary part of the pixel value of the last image
processed. Only used if the pixel type of the last input image was complex.
.le
.ls imaxval = INDEF
Set to the maximum imaginary part of the pixel value of the last image
processed. Only used if the pixel type of the last input image was complex.
.le
.ls minpix = ""
Set to the minimum pixel specification of the last image processed.
.le
.ls maxpix = ""
Set to the maximum pixel specification of the last image processed.
.le
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DESCRIPTION

    The \fIminmax\fR task computes the minimum and maximum pixel and pixel
values of
each of the images or image sections listed in the image template \fIimages\fR.
If the \fIforce\fR option is set the extreme values will be recomputed by
physical examination of the data, otherwise the image is examined only if the
extreme values stored in the image header are flagged as invalid.
The minimum and maximum pixel will be printed only if the force option
is enabled or if the image minimum and maximum is out of date. 
If the \fIupdate\fR option is set the image header will be updated with the
newly computed values.  Updating is not allowed when a section is used to
compute the new values.
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EXAMPLES
1. Compute and print the minimum and maximum values of the images \fIimage1\fR
and \fIimage2\fR, updating the image header with the new values when done.

.nf
	cl> minmax image1,image2
.fi

2. Force update the minimum and maximum values in the image headers of all
images matching the template in the background, without printing the computed
values on the terminal.

	cl> minmax nite1.* force+ verbose- &
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BUGS
The minimum and maximum pixel values are stored in the image header as values
of type real, hence some precision may be lost for images of type long integer
or double precision floating.
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SEE ALSO
imheader, hedit
.endhelp