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+.help imreplace Dec97 images.imutil
+.ih
+NAME
+imreplace -- replace pixels in a window by a constant
+.ih
+USAGE
+imreplace images value lower upper
+.ih
+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 windoe for the imaginary part of
+complex data.
+.le
+.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.
+.le
+.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.
+.le
+.ls radius = 0.
+Additional replacement radius around pixels which are in the replacement
+window. If a pixel is within this distance of a pixel within the replacement
+window it is also replaced with the replacement value. Distances are
+measured between pixel centers which are have integer coordinates.
+.le
+.ih
+DESCRIPTION
+The pixels in the \fIimages\fR between \fIlower\fR and \fIupper\fR,
+and all other pixels with a distance given by \fIradius\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 affets pixels 6-9.
+.ih
+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
+.ih
+REVISIONS
+.ls IMREPLACE V2.11.1
+A replacement radius to replace additional pixels was added.
+.le
+.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.
+.le
+.ih
+SEE ALSO
+imexpr
+.endhelp