.help imreplace Jul95 proto
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NAME
imreplace -- replace pixels in a window by a constant
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USAGE	
imreplace images value lower upper
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PARAMETERS
.ls images
Images in which the pixels are to be replaced.
.le
.ls value
Replacement value for pixels in the window.
.le
.ls imaginary = 0.
Replacement value for pixels in the window for the imaginary part of
complex data.
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.ls lower = INDEF
Lower limit of window for replacing pixels.  If INDEF then all pixels
are above \fIlower\fR.  For complex images this is the magnitude
of the pixel values.  For integer images the value is rounded up
to the next higher integer.
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.ls upper = INDEF
Upper limit of window for replacing pixels.  If INDEF then all pixels
are below \fIupper\fR.  For complex images this is the magnitude
of the pixel values.  For integer images the value is rounded down
to the next lower integer.
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DESCRIPTION
The pixels in the \fIimages\fR between \fIlower\fR and \fIupper\fR
are replaced by the constant \fIvalue\fR.  The special value INDEF in
\fIlower\fR and \fIupper\fR corresponds to the minimum and maximum
possible pixel values, respectively.

For complex images the replacement value is specified as separate
real and imaginary and the thresholds are the magnitude.  For
integer images the thresholds are used as inclusive limits
so that, for example, the range 5.1-9.9 affects pixels 6-9.
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EXAMPLES
1. In a flat field calibration which has been scaled to unit mean replace
all response values less than or equal to 0.8 by 1.

    cl> imreplace calib 1 upper=.8

2. Set all pixels to zero within a section of an image.

    cl> imreplace image[1:10,5:100] 0
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REVISIONS
.ls IMREPLACE V2.11
The lower value is now rounded up for integer images so that a range
like 5.1-9.9 affects pixels 6-9 instead of 5-9.
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SEE ALSO
imexpr
.endhelp
