.help normalize Sep84 noao.imred.generic
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NAME
normalize -- Normalize images
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USAGE	
normalize images
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PARAMETERS
.ls images
Images to be normalized.
.le
.ls norm = INDEF
Normalization factor to be used if not INDEF.  If INDEF the normalization
factor is determined by sampling the images.
.le
.ls sample_section = "[]"
Section of the image to be sampled in determining the image mean.
.le
.ls lower = INDEF
Lower limit of pixel values for calculating the normalization.
INDEF corresponds to the minimum possible pixel value.
.le
.ls upper = INDEF
Upper limit of pixel values for calculating the normalization.
INDEF corresponds to the maximum possible pixel value.
.le
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DESCRIPTION
Each of the images is normalized.  The normalization is specified by the
parameter \fInorm\fR.  If the value of \fInorm\fR is INDEF then a normalization
is determined by sampling the image.  The normalization is then the mean
of the pixels in the sample section with values in the range \fIlower\fR
to \fIupper\fR.  The default sample section selects all pixels in the image.
The normalized images are of datatype "real" and replace the original images.
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EXAMPLES
To normalize a set of two dimensional images excluding deviant pixels below
1000 and above 5000 and subsampling every fifth pixel in each dimension:

	cl> normalize frame* sample=[*:5,*:5] low=1000 up=5000
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SEE ALSO
imstatistics, normflat
.endhelp