Woolz Image Processing  Version 1.7.5
WlzDefGrdTensorFeatures
Name
WlzDefGrdTensorFeatures - computes features of deformation gradient tensor fields.
Synopsis
WlzDefGrdTensorFeatures [-d <x>,<y>,<z>] [-f <feature list>]
[-g <x>,<y>,<z>] [-h] [-o<out file>]
[-p] [-s <dst>] [-u] [-x] [<input file>]

Options
 -d Dither range for point positions (default no dithering, dithering implies a points output object). -g Smooth values using a Gaussian with the given sigma values (default no smoothing). -f Features for extraction identified by a comma separated list of single characters. -h Help, prints usage message. -p Output points objects rather than vector fields. -o Output object file. -s Minimum point seperation. If generating points objects then " this specifies the minimum distance between points. -u If a single feature is requested do not use a compound object. -x Use voxel size scaling for points objects.
Description
Computes features of the input object which must be a deformation gradient tensor field. The output is a compound object with a component object per feature, with the features identifiable through their name properties or ordering. The features for extraction may be defined by a comma separated list of single characters. Available features are:
 identifying character property name feature d eigen vectors eigen (principle direction) vectors j jacobian determinant of Jacobian tensor s eigen values eigen (principle stretch) values Default feature selection is d,j,s.

By default all files are read from the standard input and are written to the standard output.

Examples
WlzDefGrdTensorFeatures -f d -p -s 40 -d 20,20,20
-g 2,2,2 -o features.wlz dgf.wlz

Creates a compound object with a single component points object in which the point domain locations are scattered over the given field's domain with a separation of 40 voxels but then dithered by an additional range of +/-20 voxels. The principle directions are computed and smoothed using a Gaussian with sigma values of 2,2,2 prior to sampling at the point locations. The associated point values will be vector values with a vector for each principle direction. The points object will also have it's name property set to "eigen vectors". The compound object will be written to the file features.wlz.
File
WlzDefGrdTensorFeatures.c