vmarr(1)

PROGRAM
vmarr - Create a Marr type edge detection filter kernel.

SYNTAX

vmarr

-o  Marr kernel output image

[-trigger]
    trigger input

[-r]
    specify the number of rows in the kernel

[-c]
    specify the number of columns in the kernel

[-v]
    variance of the Gaussian

[-V]
    Gives the version for vmarr

[-U]
    Gives the usage for vmarr

[-P]
    Prompts for command line options

[-A [file1]]
    Creates the answer file called vmarr.ans or file1

[-a [file1]]
    Uses vmarr.ans or file1 as the answer file

DESCRIPTION
creates a convolution filter kernel using the following equation. pixel = [-1/(PI*var*var)]*[1-r*r/(2*var)]*exp[-r*r/(2*var)], where r is the calculated distance from the center of the kernel.

A Marr filter is the Laplacian of a Gaussian, and is intended for high lighting image edges and at the same time smooth out the noise. vmarr creates image data of type float.

The trigger input can be used to cause vcustom to re-execute when used inside cantata. No image is read from this input.

REQUIRED ARGUMENTS

-o  type: outfile
    desc: Marr kernel output image

OPTIONAL ARGUMENTS

-trigger
    type: infile
    desc: trigger input

-r  type: integer
    desc: specify the number of rows in the kernel
    default: 3
    bounds: value > 0

-c  type: integer
    desc: specify the number of columns in the kernel
    default: 3
    bounds: value > 0

-v  type: float
    desc: variance of the Gaussian
    default: 1
    bounds: value > 0.0

EXAMPLES

SEE ALSO
intro(1), verror(3), vgparms(3), vutils(3), lvmarr(3) vcustom(1)

RESTRICTIONS
only generates float kernels, vconvert can change the image to other data types.

COPYRIGHT
Copyright 1991, University of New Mexico. All rights reserved.