NAME

     acuity_nightvision_filter - visual  acuity  and  nightvision
     simulations

SYNOPSIS

      #include "CVIPtools.h"
      #include "CVIPtoolkit.h"
      #include "CVIPconvert.h"
      #include "CVIPimage.h"
      #include "CVIPdef.h"
      #include "CVIPfs.h"
      #include "CVIPhisto.h"
      #include "threshold.h"
      #include "CVIPspfltr.h"

     Image *acuity_nightvision_filter(Image *cvipImage,char  rea-
     son, int threshold, int choice)

      <cvipImage> - pointer to an Image
      <reason> - y = nightvision, n = acuity simulation
      <threshold> - binary threshold for nightvision simulation
      <choice> - visual acuity value (20, 30, 40, ...)

PATH

     $CVIPHOME/SPATIALFILTER/nightvision.c

DESCRIPTION

     Performs visual acuity and nightvision goggles  simulations.
     For  visual  acuity, set <reason> to 'n', set <threshold> to
     -1, and specify the desired acuity <choice> as the numerator
     of a standard visual acuity rating, such as '50' to simulate
     20/50 vision.

     For nightvision goggles simulation,  set  <reason>  to  'y',
     select a threshold value (1-154), and set <choice> to -1.

TYPES AND CONSTANTS

     None

RETURN VALUES

     A modified image

HISTORY

     History information recorded: None

SEE ALSO

     libspatialfiltr

AUTHOR

     Copyright (C) 1996 SIUE - by Scott Umbaugh,  Mark  Zuke  and
     Kun Luo.