IMAGE commands


PROGRAM NAME

imedian - Median Filter for Image Data

DESCRIPTION

imedian performs median filtering on image data. The method is as follows: for each WSIZExHSIZE window in the image, replace the pixel at (WSIZE/2)x(HSIZE/2) (integer arithmetic) with the median of the values in the window. The median is computed by sorting the values in the window with quicksort and extracting the middle value as the median. This is not the fastest approach for BYTE data where a histogram updating method could be used. It is, however, extensible to higher data types including floating point data.

If a map is present, the data is mapped prior to operation. Mask data is ignored.

This implementation processes the image data by full planes.

Boundaries are handled by zero padding.

REQUIRED ARGUMENTS

-i
type: infile
desc: Input image
-o
type: outfile
desc: Output image

OPTIONAL ARGUMENTS

-wsize
type: integer
desc: Width of window
default: 3
bounds: value > 0
-hsize
type: integer
desc: Heigth of window
default: 3
bounds: value > 0
-reps
type: integer
desc: number of repetitions of filter to perform
default: 1
bounds: value >= 0

EXAMPLES

SEE ALSO

RESTRICTIONS

Complex data types are not supported.

The ability to process by partial planes will be added at a future time, permitting more efficient operation on images large in the W and H dimensions.

At some point, the faster histogram updating technique should be stolen from K1.5 lvhmed(3) and put in place for BYTE processing.

REFERENCES

COPYRIGHT

Copyright (C) 1993 - 1997, Khoral Research, Inc. ("KRI") All rights reserved.