pkfilter

pkfilter

program to filter raster images

SYNOPSIS

Usage: pkfilter -i input -o ouptut [-f filter | -srf file [-srf file]* | -fwhm value [-fwhm value]*]

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Options: [-dx value [-dy value] | -dz value] [-nodata value]

This utility implements spatial and spectral filtering for raster data. In the spatial domain (X, Y), the filter typically involves a rectangular convolution kernel (moving window). To avoid image shifting, the size of the window should be odd (3, 5, 7, ...). You can set the window sizes in X and Y directions separately with the options -dx and -dy. A circular kernel (disc) is applied if option -circ is set. An overview of the supported filters (option -f|–filter) is given below. You can create customized filters by defining your own filter taps (multiplicative elements of the filter kernel) via an ascii file (option -tap). In the spectral/temporal domain (Z) you can filter multi-band raster inputs. The kernel filter size can be set with the option -dz (use odd values only).

Options

• use either -short or --long options (both --long=value and --long value are supported)
• short option -h shows basic options only, long option --help shows all options

  short	long	type	default	description
  i	input	std::string		input image file
  o	output	std::string		Output image file
  f	filter	std::string	median	filter function (median, var, min, max, sum, mean, dilate, erode, close, open, homog (central pixel must be identical to all other pixels within window), heterog, sobelx (horizontal edge detection), sobely (vertical edge detection), sobelxy (diagonal edge detection NE-SW),sobelyx (diagonal edge detection NW-SE), smooth, density, countid, mode (majority voting, only for classes), smoothnodata (smooth nodata values only) values, threshold local filtering, ismin, ismax, heterogeneous (central pixel must be different than all other pixels within window), order (rank pixels in order), stdev, mrf, dwt, dwti, dwt_cut, dwt_cut_from, scramble, shift, linearfeature, savgolay)
  srf	srf	std::string		list of ASCII files containing spectral response functions (two columns: wavelength response)
  fwhm	fwhm	double		list of full width half to apply spectral filtering (-fwhm band1 -fwhm band2 ...)
  dx	dx	double	3	filter kernel size in x, better use odd value to avoid image shift
  dy	dy	double	3	filter kernel size in y, better use odd value to avoid image shift
  dz	dz	int		filter kernel size in z (band or spectral dimension), must be odd (example: 3).. Set dz>0 if 1-D filter must be used in band domain
  nodata	nodata	double		nodata value(s) (used for smoothnodata filter)
  r	resampling-method	std::string	near	Resampling method for shifting operation (near: nearest neighbour, bilinear: bi-linear interpolation).
  co	co	std::string		Creation option for output file. Multiple options can be specified.
  wt	wavelet	std::string	daubechies	wavelet type: daubechies,daubechies_centered, haar, haar_centered, bspline, bspline_centered
  nl	nl	int	2	Number of leftward (past) data points used in Savitzky-Golay filter)
  nr	nr	int	2	Number of rightward (future) data points used in Savitzky-Golay filter)
  ld	ld	int	0	order of the derivative desired in Savitzky-Golay filter (e.g., ld=0 for smoothed function)
  m	m	int	2	order of the smoothing polynomial in Savitzky-Golay filter, also equal to the highest conserved moment; usual values are m = 2 or m = 4)
  class	class	short		class value(s) to use for density, erosion, dilation, openening and closing, thresholding
  t	threshold	double	0	threshold value(s) to use for threshold filter (one for each class), or threshold to cut for dwt_cut (use 0 to keep all) or dwt_cut_from, or sigma for shift
  tap	tap	std::string		text file containing taps used for spatial filtering (from ul to lr). Use dimX and dimY to specify tap dimensions in x and y. Leave empty for not using taps
  tapz	tapz	double		taps used for spectral filtering
  pad	pad	std::string	symmetric	Padding method for filtering (how to handle edge effects). Choose between: symmetric, replicate, circular, zero (pad with 0).
  win	wavelengthIn	double		list of wavelengths in input spectrum (-win band1 -win band2 ...)
  wout	wavelengthOut	double		list of wavelengths in output spectrum (-wout band1 -wout band2 ...)
  d	down	short	1	down sampling factor. Use value 1 for no downsampling). Use value n>1 for downsampling (aggregation)
  beta	beta	std::string		ASCII file with beta for each class transition in Markov Random Field
  eps	eps	double	0	error marging for linear feature
  l1	l1	bool	false	obtain longest object length for linear feature
  l2	l2	bool	false	obtain shortest object length for linear feature
  a1	a1	bool	false	obtain angle found for longest object length for linear feature
  a2	a2	bool	false	obtain angle found for shortest object length for linear feature
  interp	interp	std::string	akima	type of interpolation for spectral filtering (see http://www.gnu.org/software/gsl/manual/html_node/Interpolation-Types.html)
  ot	otype	std::string		Data type for output image ({Byte/Int16/UInt16/UInt32/Int32/Float32/Float64/CInt16/CInt32/CFloat32/CFloat64}). Empty string: inherit type from input image
  of	oformat	std::string		Output image format (see also gdal_translate). Empty string: inherit from input image
  ct	ct	std::string		color table (file with 5 columns: id R G B ALFA (0: transparent, 255: solid). Use none to ommit color table
  circ	circular	bool	false	circular disc kernel for dilation and erosion

  Usage: pkfilter -i input -o ouptut [-f filter | -srf file [-srf file]* | -fwhm value [-fwhm value]*]

Examples

Some examples how to use pkfilter can be found here