venhance(1)

PROGRAM
venhance - Enhances an image using the local standard deviation and mean.

SYNTAX

venhance

-i  input image filename

-o  output image filename

-w  window width of local area

-h  window height of local area

-k  specifies scale factor

-v  specifies minimum standard deviation

[-V]
    Gives the version for venhance

[-U]
    Gives the usage for venhance

[-P]
    Prompts for command line options

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

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

DESCRIPTION
venhance uses a local transformation based on the mean and variance of the intensity maps and the intensity of the input image f(x,y) to create a new image g(x,y) by performing the following transformation at each pixel location (x,y):
        g(x,y) = A(x,y).[f(x,y) -m(x,y)] + m(x,y),
where
        A(x,y) = k . M / sigma(x,y)     0 < k < 1

where m(x,y) and sigma(x,y) are the gray-level mean and standard deviation computed in a neighborhood centered at (x,y), M is the global mean of f(x,y), and k is a constant in the range indicated above.

REQUIRED ARGUMENTS

-i  type: infile
    desc: input image filename

-o  type: outfile
    desc: output image filename

-w  type: integer
    desc: window width of local area

-h  type: integer
    desc: window height of local area

-k  type: float
    desc: specifies scale factor

-v  type: float
    desc: specifies minimum standard deviation

OPTIONAL ARGUMENTS
none

EXAMPLES
venhance -i input.image -o output.image -w 5 -h 5 -k .5 -v 2

This command performs image enhancement on input.image and stores the result in output.image. The size of the window used is 5 by 5. The tuning factor is .5 and the minimum allowable standard deviation is 2.

SEE ALSO
intro(1), verror(3), vgparms(3), vutils(3), lvenhance(3)

Reference: Digital Image Processing (2nd Edition) by Gonzalez and Wintz.

RESTRICTIONS
venhance only operates on byte type images.

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