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Pgmmedian User Manual(0) Pgmmedian User Manual(0)NAMEpgmmedian - apply a median filter to a PGM fileSYNOPSISpgmmedian[-width=n] [-height=n] [-type=median_type] [-cutoff=int] [pnmfile] Minimum unique abbreviation of option is acceptable. You may use double hyphens instead of single hyphen to denote options. You may use white space in place of the equals sign to separate an option name from its value.DESCRIPTIONThis program is part of Netpbm(1).pgmmedianapplies a median filter to a PGM image, using either the histogram sort or select kth value method to determine the median. See the-typeand-cutoffoptions for information on howpgmmedianchooses between the two methods.OPTIONS-cutoffintThis option provides the cutoff value thatpgmmedianuses to decide between using the histogram sort or select kth value method to find the median. If (maxval/ ((width*height) - 1)), wheremaxvalis the maxval of the image andwidthandheightare the dimensions of the mask, is less than the cutoff value,pgmmedianuses histogram sort. Otherwise, it uses kth value. If expression is less than the cutoff,pgmmedianuses the histogram sort. Otherwise it uses the select kth value method. This option has no effect if you specify-type. The default is 250-width=nWidth of the median mask to apply. Default is 3.-height=nHeight of the median mask to apply. Default is 3.-typemedian_typeThis option selects which method to use to find median regardless of cutoff value. Choices arehis-togram_sortandselect. By default,pgmmediandecides which method to use as described under the-cutoffoption.REFERENCES? 'Collected Algorithms from ACM' Volume II, Algorithm 489 by Robert W. Floyd ? 'A Fast Two-Dimensional Median Filtering Algorithm' in 'IEEE Transactions on Acoustics, Speech, and Sig- nal Processing' Vol. ASSP-27, No. 1, February 1979 ? 'Digital Image Processing Algorithms' by Ioannis Pitas, Prentice Hall, 1993 ISBN 0-13-145814-0SEEALSOpgmnoise(1), pamaddnoise(1), pgm(1)HISTORYpgmmedianwas added to Netpbm in Version 10.29 (August 2005). It had been distributed by Mike Burns via his own web site before that (and continued to be so).AUTHORCopyright (C) 1996 by Mike Burns <burns> netpbm documentation 28 August 2005 Pgmmedian User Manual(0)ATcac.edu