NAME

imreplace -- replace pixels in a window by a constant

USAGE

imreplace images value lower upper

PARAMETERS

images

Images in which the pixels are to be replaced.

value

Replacement value for pixels in the window.

imaginary = 0.

Replacement value for pixels in the windoe for the imaginary part of complex data.

lower = INDEF

Lower limit of window for replacing pixels. If INDEF then all pixels are above lower . For complex images this is the magnitude of the pixel values. For integer images the value is rounded up to the next higher integer.

upper = INDEF

Upper limit of window for replacing pixels. If INDEF then all pixels are below upper . For complex images this is the magnitude of the pixel values. For integer images the value is rounded down to the next lower integer.

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.

DESCRIPTION

The pixels in the images between lower and upper , and all other pixels with a distance given by radius , are replaced by the constant value . The special value INDEF in lower and upper 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.

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

REVISIONS

IMREPLACE V2.11.1

A replacement radius to replace additional pixels was added.

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.

SEE ALSO

imexpr